android的文件操作

android的文件操作要有权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

SD卡下的文件操作：

1、判断SD卡是否插入

Environment.getExternalStorageState().equals( android.os.Environment.MEDIA_MOUNTED);

2、获得sd卡根目录：

File skRoot = Environment.getExternalStorageDirectory();

私有目录下的文件操作：

1、获得私有根目录：

File fileRoot = Context.getFilesDir()+"//";

还未整理

文件夹或文件夹操作：

1、确定或获得文件夹和文件路径

a、获得文件或文件夹的绝对路径和相对路径

String path = File.getPath();//相对String path = File.getAbsoultePath();//绝对

b 、获得文件或文件夹的父目录

String parentPath = File.getParent();

c、获得文件或文件夹的名称：

String Name = File.getName();

2、建立文件或文件夹

File.mkDir(); //建立文件夹File.createNewFile();//建立文件

3、判断是文件或文件夹

File.isDirectory()

4、列出文件夹下的所有文件和文件夹名

File[] files = File.listFiles();

5、修改文件夹和文件名

File.renameTo(dest);

6、删除文件夹或文件

File.delete();

java代码：

package otheri.common;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import otheri.io.Input;import otheri.io.Output;import android.content.Context;import android.os.Environment;public class FileHelper {private Context context;private String SDPATH;private String FILESPATH;public FileHelper(Context context) {this.context = context;SDPATH = Environment.getExternalStorageDirectory().getPath() + "//";FILESPATH = this.context.getFilesDir().getPath() + "//";}/** * 在SD卡上创建文件 * * @throws IOException */public File creatSDFile(String fileName) throws IOException {File file = new File(SDPATH + fileName);file.createNewFile();return file;}/** * 删除SD卡上的文件 * * @param fileName */public boolean delSDFile(String fileName) {File file = new File(SDPATH + fileName);if (file == null || !file.exists() || file.isDirectory())return false;file.delete();return true;}/** * 在SD卡上创建目录 * * @param dirName */public File creatSDDir(String dirName) {File dir = new File(SDPATH + dirName);dir.mkdir();return dir;}/** * 删除SD卡上的目录 * * @param dirName */public boolean delSDDir(String dirName) {File dir = new File(SDPATH + dirName);return delDir(dir);}/** * 修改SD卡上的文件或目录名 * * @param fileName */public boolean renameSDFile(String oldfileName, String newFileName) {File oleFile = new File(SDPATH + oldfileName);File newFile = new File(SDPATH + newFileName);return oleFile.renameTo(newFile);}/** * 拷贝SD卡上的单个文件 * * @param path * @throws IOException */public boolean copySDFileTo(String srcFileName, String destFileName)throws IOException {File srcFile = new File(SDPATH + srcFileName);File destFile = new File(SDPATH + destFileName);return copyFileTo(srcFile, destFile);}/** * 拷贝SD卡上指定目录的所有文件 * * @param srcDirName * @param destDirName * @return * @throws IOException */public boolean copySDFilesTo(String srcDirName, String destDirName)throws IOException {File srcDir = new File(SDPATH + srcDirName);File destDir = new File(SDPATH + destDirName);return copyFilesTo(srcDir, destDir);}/** * 移动SD卡上的单个文件 * * @param srcFileName * @param destFileName * @return * @throws IOException */public boolean moveSDFileTo(String srcFileName, String destFileName)throws IOException {File srcFile = new File(SDPATH + srcFileName);File destFile = new File(SDPATH + destFileName);return moveFileTo(srcFile, destFile);}/** * 移动SD卡上的指定目录的所有文件 * * @param srcDirName * @param destDirName * @return * @throws IOException */public boolean moveSDFilesTo(String srcDirName, String destDirName)throws IOException {File srcDir = new File(SDPATH + srcDirName);File destDir = new File(SDPATH + destDirName);return moveFilesTo(srcDir, destDir);}/* * 将文件写入sd卡。如:writeSDFile("test.txt"); */public Output writeSDFile(String fileName) throws IOException {File file = new File(SDPATH + fileName);FileOutputStream fos = new FileOutputStream(file);return new Output(fos);}/* * 在原有文件上继续写文件。如:appendSDFile("test.txt"); */public Output appendSDFile(String fileName) throws IOException {File file = new File(SDPATH + fileName);FileOutputStream fos = new FileOutputStream(file, true);return new Output(fos);}/* * 从SD卡读取文件。如:readSDFile("test.txt"); */public Input readSDFile(String fileName) throws IOException {File file = new File(SDPATH + fileName);FileInputStream fis = new FileInputStream(file);return new Input(fis);}/** * 建立私有文件 * * @param fileName * @return * @throws IOException */public File creatDataFile(String fileName) throws IOException {File file = new File(FILESPATH + fileName);file.createNewFile();return file;}/** * 建立私有目录 * * @param dirName * @return */public File creatDataDir(String dirName) {File dir = new File(FILESPATH + dirName);dir.mkdir();return dir;}/** * 删除私有文件 * * @param fileName * @return */public boolean delDataFile(String fileName) {File file = new File(FILESPATH + fileName);return delFile(file);}/** * 删除私有目录 * * @param dirName * @return */public boolean delDataDir(String dirName) {File file = new File(FILESPATH + dirName);return delDir(file);}/** * 更改私有文件名 * * @param oldName * @param newName * @return */public boolean renameDataFile(String oldName, String newName) {File oldFile = new File(FILESPATH + oldName);File newFile = new File(FILESPATH + newName);return oldFile.renameTo(newFile);}/** * 在私有目录下进行文件复制 * * @param srcFileName * ： 包含路径及文件名 * @param destFileName * @return * @throws IOException */public boolean copyDataFileTo(String srcFileName, String destFileName)throws IOException {File srcFile = new File(FILESPATH + srcFileName);File destFile = new File(FILESPATH + destFileName);return copyFileTo(srcFile, destFile);}/** * 复制私有目录里指定目录的所有文件 * * @param srcDirName * @param destDirName * @return * @throws IOException */public boolean copyDataFilesTo(String srcDirName, String destDirName)throws IOException {File srcDir = new File(FILESPATH + srcDirName);File destDir = new File(FILESPATH + destDirName);return copyFilesTo(srcDir, destDir);}/** * 移动私有目录下的单个文件 * * @param srcFileName * @param destFileName * @return * @throws IOException */public boolean moveDataFileTo(String srcFileName, String destFileName)throws IOException {File srcFile = new File(FILESPATH + srcFileName);File destFile = new File(FILESPATH + destFileName);return moveFileTo(srcFile, destFile);}/** * 移动私有目录下的指定目录下的所有文件 * * @param srcDirName * @param destDirName * @return * @throws IOException */public boolean moveDataFilesTo(String srcDirName, String destDirName)throws IOException {File srcDir = new File(FILESPATH + srcDirName);File destDir = new File(FILESPATH + destDirName);return moveFilesTo(srcDir, destDir);}/* * 将文件写入应用私有的files目录。如:writeFile("test.txt"); */public Output wirteFile(String fileName) throws IOException {OutputStream os = context.openFileOutput(fileName,Context.MODE_WORLD_WRITEABLE);return new Output(os);}/* * 在原有文件上继续写文件。如:appendFile("test.txt"); */public Output appendFile(String fileName) throws IOException {OutputStream os = context.openFileOutput(fileName, Context.MODE_APPEND);return new Output(os);}/* * 从应用的私有目录files读取文件。如:readFile("test.txt"); */public Input readFile(String fileName) throws IOException {InputStream is = context.openFileInput(fileName);return new Input(is);}/**********************************************************************************************************//*********************************************************************************************************/ *//** * 删除一个文件 * * @param file * @return */public boolean delFile(File file) {if (file.isDirectory())return false;return file.delete();}/** * 删除一个目录（可以是非空目录） * * @param dir */public boolean delDir(File dir) {if (dir == null || !dir.exists() || dir.isFile()) {return false;}for (File file : dir.listFiles()) {if (file.isFile()) {file.delete();} else if (file.isDirectory()) {delDir(file);// 递归}}dir.delete();return true;}/** * 拷贝一个文件,srcFile源文件，destFile目标文件 * * @param path * @throws IOException */public boolean copyFileTo(File srcFile, File destFile) throws IOException {if (srcFile.isDirectory() || destFile.isDirectory())return false;// 判断是否是文件FileInputStream fis = new FileInputStream(srcFile);FileOutputStream fos = new FileOutputStream(destFile);int readLen = 0;byte[] buf = new byte[1024];while ((readLen = fis.read(buf)) != -1) {fos.write(buf, 0, readLen);}fos.flush();fos.close();fis.close();return true;}/** * 拷贝目录下的所有文件到指定目录 * * @param srcDir * @param destDir * @return * @throws IOException */public boolean copyFilesTo(File srcDir, File destDir) throws IOException {if (!srcDir.isDirectory() || !destDir.isDirectory())return false;// 判断是否是目录if (!destDir.exists())return false;// 判断目标目录是否存在File[] srcFiles = srcDir.listFiles();for (int i = 0; i < srcFiles.length; i++) {if (srcFiles[i].isFile()) {// 获得目标文件File destFile = new File(destDir.getPath() + "//"+ srcFiles[i].getName());copyFileTo(srcFiles[i], destFile);} else if (srcFiles[i].isDirectory()) {File theDestDir = new File(destDir.getPath() + "//"+ srcFiles[i].getName());copyFilesTo(srcFiles[i], theDestDir);}}return true;}/** * 移动一个文件 * * @param srcFile * @param destFile * @return * @throws IOException */public boolean moveFileTo(File srcFile, File destFile) throws IOException {boolean iscopy = copyFileTo(srcFile, destFile);if (!iscopy)return false;delFile(srcFile);return true;}/** * 移动目录下的所有文件到指定目录 * * @param srcDir * @param destDir * @return * @throws IOException */public boolean moveFilesTo(File srcDir, File destDir) throws IOException {if (!srcDir.isDirectory() || !destDir.isDirectory()) {return false;}File[] srcDirFiles = srcDir.listFiles();for (int i = 0; i < srcDirFiles.length; i++) {if (srcDirFiles[i].isFile()) {File oneDestFile = new File(destDir.getPath() + "//"+ srcDirFiles[i].getName());moveFileTo(srcDirFiles[i], oneDestFile);delFile(srcDirFiles[i]);} else if (srcDirFiles[i].isDirectory()) {File oneDestFile = new File(destDir.getPath() + "//"+ srcDirFiles[i].getName());moveFilesTo(srcDirFiles[i], oneDestFile);delDir(srcDirFiles[i]);}}return true;}}

getPath与getAbsoultePath的区别:

getAbsolutePath()：返回抽象路径名的绝对路径名字符串。

public static void test1(){ File file1 = new File(".//test1.txt"); File file2 = new File("D://workspace//test//test1.txt"); System.out.println("-----默认相对路径：取得路径不同------"); System.out.println(file1.getPath()); System.out.println(file1.getAbsolutePath()); System.out.println("-----默认绝对路径:取得路径相同------"); System.out.println(file2.getPath()); System.out.println(file2.getAbsolutePath()); }-----默认相对路径：取得路径不同------./test1.txtD:/workspace/test/./test1.txt-----默认绝对路径:取得路径相同------D:/workspace/test/test1.txtD:/workspace/test/test1.txt----------------------------------------------------public static void test2() throws Exception{ File file = new File("..//src//test1.txt"); System.out.println(file.getAbsolutePath()); System.out.println(file.getCanonicalPath()); }D:/workspace/test/../src/test1.txtD:/workspace/src/test1.txt--------------------------------------------public static void test3() throws Exception{ File file = new File("D://Text.txt"); System.out.println(file.getCanonicalPath());

(1),确定D盘下没有Text.txt这个文件，直接执行这段代码，得到的结果是:
D:/Text.txt注意这里试大写的Text.txt
(2)在D盘下建立一个文件，名叫text.txt，再次执行代码，得到结果
D:/text.txt同样的代码得到不同的结果。