黑马程序员——Java学习总结：IO常用方法练习
来源：互联网 发布：阿里云域名优惠 2017 编辑：程序博客网 时间：2024/05/20 01:45
前几天写过了IO学习总结，还是感觉对知识掌握理解的不够透彻，今天特意进行的IO部分的练习，个人感觉还是写写代码、看代码、看注释、查API学习的比较快，并掌握的表牢靠。现将练习整理如下。路过高手请赐教。
File类常见方法练习：
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.IOException;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.text.SimpleDateFormat;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.Date;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FileTest01</span> {</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//创建File实例的方法 1</span> File file=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\abc\\abc.txt"</span>); File file1=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\abc\\mkdir"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//创建File实例的方法 2</span> File file2=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\abc"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"hello.txt"</span>); File file3=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"abc.txt"</span>); File file4=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\abc\\d\\e\\f"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//在多系统上扩展</span> File file5=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:"</span>+File.separator+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"abc"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//File的常见操作方法：</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//1.获取名称</span> String strName=file.getName(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"名称:"</span>+strName); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//2.获取大小</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> fileSize=file.length(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"大小："</span>+fileSize); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//文件存在，返回文件长度，文件不存在，所以返回0</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//3.获取类型</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//因为类型不定，无法获取类型</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//4.获取目录</span> String strParent=file.getParent(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"目录："</span>+strParent); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//5.获取绝对路径</span> String strAbsolutePath=file3.getAbsolutePath(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"绝对地址："</span>+strAbsolutePath); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//6.获取路径</span> String strPath=file3.getPath(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"地址："</span>+strPath); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//7.获取最后一次修改时间</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> lastModify=file.lastModified(); Date date=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Date(lastModify); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// DateFormat df=DateFormat.getDateInstance(DateFormat.FULL);</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// String strDate=df.format(date);</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// System.out.println("上次修改的时间"+strDate);</span> SimpleDateFormat sdf=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> SimpleDateFormat(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"yyyy/MM/dd hh:mm:ss"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//自定义日期格式</span> String strDate=sdf.format(date); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"上次修改的时间"</span>+strDate); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//8.文件是否隐藏</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> isHidden=file.isHidden(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"隐藏"</span>+isHidden); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//9.创建文件</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag=file2.createNewFile(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//已经存在则不能创建，返回false,不存在创建，返回true</span> System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"创建文件"</span>+flag); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//10.删除文件</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag1=file2.delete(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"删除文件"</span>+flag1); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//11.创建文件夹</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag2=file1.mkdir(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"创建文件："</span>+flag2); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//12.创建多级文件夹</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag3=file4.mkdirs(); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"创建多级文件："</span>+flag3); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//13.删除文件夹</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag4=file1.delete(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag5=file4.delete(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//删除时候必须保证文件夹下无内容</span> System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"删除文件："</span>+flag4); System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"删除文件："</span>+flag5); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//14.getFreeSpace() getTotalSpace() getUsableSpace() </span> File file14=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\"</span>); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> freeSpace=file14.getFreeSpace(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//得到指定目录的可用空间</span> System.out.println(freeSpace); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> totalSpace=file14.getTotalSpace(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//得到指定目录的总共空间</span> System.out.println(totalSpace); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> usableSpace=file14.getUsableSpace(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//得到指定目录的已用空间</span> System.out.println(usableSpace); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//15.获取指定文件下文件和文件夹的名称</span> File file15=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\"</span>); String[] arrs=file15.list(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(String str:arrs){ System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"文件名："</span>+str); } File[] arrayFile=file15.listFiles(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File f:arrayFile){ System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"文件夹名："</span>+f); } <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//16.获得指定文件夹下的.txt文件</span> File file16=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\"</span>); getSuffix(file16,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">".txt"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//17.获得部分名称的文件</span> File file17=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\"</span>); getFileByPartOfName(file17,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"hello"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//18.文件过滤器 FileFilter</span> File file18 = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\"</span>); File[] arrsfile=file18.listFiles(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> MyFileFilter(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">".txt"</span>)); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File f:arrsfile) System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"FileFilter: "</span>+f); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//19 获取指定目录下的内容，包含子目录下内容。 递归思想</span> File file19=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\abc"</span>); getFileFromDir(file19); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">getFileFromDir</span>(File file19) { File[] arrfile=file19.listFiles(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File file:arrfile){ <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (file.isDirectory()) { System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"文件夹："</span>+file); getFileFromDir(file); }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"文件："</span>+file); } } } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">getFileByPartOfName</span>(File file, String string) { String[] arrs=file.list(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FilterByPartOfName(string)); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(String str:arrs){ System.out.println(string+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"文件："</span>+str); } } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">getSuffix</span>(File file,String string) { String[] arrs=file.list(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FilterBySuffix(string)); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(String str:arrs){ System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">".txt文件："</span>+str); } }}----------<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** * FilenameFilter文件名过滤器 * 用于过滤文件名中包含的特定字符串的的文件 */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FilenameFilter;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FilterByPartOfName</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FilenameFilter</span> {</span> String name; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">FilterByPartOfName</span>(String name) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.name = name; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">accept</span>(File arg0, String arg1) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> arg1.contains(name); }}----------<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FilenameFilter;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** * 文件名过滤器，可用于过滤特定的文件类型。 *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> hsf * */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FilterBySuffix</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FilenameFilter</span> {</span> String name; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> name */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">FilterBySuffix</span>(String name) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.name = name; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">accept</span>(File arg0, String arg1) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> arg1.endsWith(name); }}----------<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** * FileFilter 文件过滤器，既可以过滤文件，也可以过滤文件名， * 过滤文件时使用File.getName().endwith(".txt"); * file.isFile();文件 * file.isDirectory(); 是文件夹 */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FileFilter;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyFileFilter</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FileFilter</span> {</span> String condition; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">MyFileFilter</span>(String condition) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.condition=condition; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">accept</span>(File passName) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> passName.isDirectory(); }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; 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padding: 0px 5px;">186</li><li style="box-sizing: border-box; padding: 0px 5px;">187</li><li style="box-sizing: border-box; padding: 0px 5px;">188</li><li style="box-sizing: border-box; padding: 0px 5px;">189</li><li style="box-sizing: border-box; padding: 0px 5px;">190</li><li style="box-sizing: border-box; padding: 0px 5px;">191</li><li style="box-sizing: border-box; padding: 0px 5px;">192</li><li style="box-sizing: border-box; padding: 0px 5px;">193</li><li style="box-sizing: border-box; padding: 0px 5px;">194</li><li style="box-sizing: border-box; padding: 0px 5px;">195</li><li style="box-sizing: border-box; padding: 0px 5px;">196</li><li style="box-sizing: border-box; padding: 0px 5px;">197</li><li style="box-sizing: border-box; padding: 0px 5px;">198</li><li style="box-sizing: border-box; padding: 0px 5px;">199</li><li style="box-sizing: border-box; padding: 0px 5px;">200</li><li style="box-sizing: border-box; padding: 0px 5px;">201</li><li style="box-sizing: border-box; padding: 0px 5px;">202</li><li style="box-sizing: border-box; padding: 0px 5px;">203</li><li style="box-sizing: border-box; padding: 0px 5px;">204</li><li style="box-sizing: border-box; padding: 0px 5px;">205</li><li style="box-sizing: border-box; padding: 0px 5px;">206</li><li style="box-sizing: border-box; padding: 0px 5px;">207</li><li style="box-sizing: border-box; padding: 0px 5px;">208</li><li style="box-sizing: border-box; padding: 0px 5px;">209</li><li style="box-sizing: border-box; padding: 0px 5px;">210</li><li style="box-sizing: border-box; padding: 0px 5px;">211</li><li style="box-sizing: border-box; padding: 0px 5px;">212</li><li style="box-sizing: border-box; padding: 0px 5px;">213</li><li style="box-sizing: border-box; padding: 0px 5px;">214</li><li style="box-sizing: border-box; padding: 0px 5px;">215</li><li style="box-sizing: border-box; padding: 0px 5px;">216</li><li style="box-sizing: border-box; padding: 0px 5px;">217</li><li style="box-sizing: border-box; padding: 0px 5px;">218</li><li style="box-sizing: border-box; padding: 0px 5px;">219</li></ul>代码运行自己需要修改File中的路径，指定为当前电脑上的路径。
需求：删除一个带内容的文件夹，内容可以是文件，也可是是文件夹。
分析：
1.指定file
2.如果文件夹中不空，文件夹是不允许删除的，所以必须先删除文件夹中的文件。
3.文件夹是嵌套的，需要使用递归的思想解决。
4.迭代过程中，是文件夹进行函数递归调用，不是文件夹进行删除，迭代到最后一个文件夹后，依次删除文件夹。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> hsf * 需求：删除一个带内容的文件夹，内容可以是文件，也可是是文件夹。 * 分析：1.指定file * 2.如果文件夹中不空，文件夹是不允许删除的，所以必须先删除文件夹中的文件。 * 3.文件夹是嵌套的，需要使用递归的思想解决。 * 4.迭代过程中，是文件夹进行函数递归调用，不是文件夹进行删除，迭代到最后一个文件夹后，依次删除文件夹。 */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FileTest02</span> {</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) { File dir=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E:\\a"</span>); deleteFile(dir); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">deleteFile</span>(File dir) { File[] arrsFile=dir.listFiles();<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获取文件夹中的内容，存储到File数组中，便于遍历。</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File f:arrsFile){ <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//执行遍历</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (f.isDirectory()) { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//是文件夹进行迭代</span> deleteFile(f); }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"删除file:"</span>+f.delete()); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//不是文件夹进行删除</span> } } System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"删除dir:"</span>+dir.delete()); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//删除文件夹 </span> } }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li></ul>需求：
获取指定文件夹下的所有.txt文件，包括子文件夹。
思路分析:
1.包含子目录，用递归函数。
2.获取指定文件，用顾虑器FileFilter
3.迭代循环，若是文件夹，进行函数递归，若是文件使用过滤区过滤，添加到集合中。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.ArrayList;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.List;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** * 获取指定文件夹下的所有.txt文件，包括子文件夹。 *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> hsf * 思路分析: * 1.包含子目录，用递归函数。 * 2.获取指定文件，用顾虑器FileFilter * 3.迭代循环，若是文件夹，进行函数递归，若是文件使用过滤区过滤，添加到集合中。 * */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Test03</span> {</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//1.定义集合存储.txt文件</span> List<File> list=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ArrayList<File>(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//2.指定目录</span> File file=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E://A"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//3 .定义过滤器</span> MyFilterBySuffix filter=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> MyFilterBySuffix(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">".txt"</span>); recution(list,file,filter); show(list); } <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//4 .定义递归函数</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">recution</span>(List<File> list,File file,MyFilterBySuffix filter){ File[] arrsFile=file.listFiles(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File f : arrsFile) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (f.isDirectory()) { recution(list, f, filter); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//执行函数递归调用</span> }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { filter.accept(f); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//进行过滤文件</span> list.add(f); } } } <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//输出list验证结果</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">show</span>(List<File> list){ <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(File file:list){ System.out.println(file); } }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li></ul><code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FileFilter;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*** * 定义文件夹过滤器 *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> hsf * */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyFilterBySuffix</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FileFilter</span> {</span> String str=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> str过滤条件 */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">MyFilterBySuffix</span>(String str) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.str = str; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">accept</span>(File file) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> file.getName().endsWith(str); }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>将数据写入文件中，并处理异常！
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> day21_IO;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FileNotFoundException;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FileOutputStream;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.IOException;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * 将数据写入文件中，并处理异常 * 步骤： * 1 指定目录 * 2 创建字节输出流 * 3 调用字节输出流写的功能 * 4 释放资源 * * 注意 异常的处理 *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> hsf * */</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">OutputStream_Test01</span> {</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//1 指定目录</span> File dir=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E://ab"</span>); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (!dir.exists()) { dir.mkdir(); } FileOutputStream fos=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//2 创建字节输出流，必须指出输出流目的地。可能存在文件不存异常FileNotFoundException，原因：该文件被系统保护，不能访问。该文件是一个目录，无法写入</span> fos=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FileOutputStream(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"E://ab//fos.txt"</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//3 调用字节输出流写功能,可能存在的写入失败异常，例如硬盘写满没有空间。</span> fos.write(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"abcdefg"</span>.getBytes()); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e) { System.out.println(e.toString()+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"----"</span>); }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">finally</span>{ <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (fos!=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> { fos.close(); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> RuntimeException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>+e); } } } }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li></ul>练习完成，分析注释都比较详细。
自己个人的总结有什么不好的地方希望高手指点
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