黑马程序员--IO流操作(1)

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1.字符流：

1.1 Reader类

1.2 Writer类

1.3 使用字符流对文件进行复制：

public class CopyText {public static void main(String[] args) {// TODO Auto-generated method stubFileReader fr = null;//声明字符流输入与输出对象FileWriter fw = null;try {fr = new FileReader("D:\\unintall.log");fw = new FileWriter("D:\\3.txt");char[] buf = new char[1024];int len = 0;while ((len = fr.read(buf)) != -1) {//读取和写入数据fw.write(buf, 0, len);}} catch (Exception e) {// TODO: handle exception} finally {if (fw != null) {try {fw.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if (fr != null) {try {fr.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}}

1.4 使用字符流缓冲区，提高对数据的读写效率：

public class CopyText2 {public static void main(String[] args) throws IOException {// TODO Auto-generated method stubBufferedReader in = new BufferedReader(new FileReader("D:\\1.txt"));BufferedWriter out = new BufferedWriter(new FileWriter("D:\\2.txt"));String buf = null;while((buf = in.readLine())!=null){out.write(buf);out.newLine();out.flush();}in.close();out.close();}}

2.字节流

2.1 InputStream

2. 2 OutputStream

2.3 使用字节流对文件进行复制：

                FileInputStream fis = new FileInputStream("E:\\2.rar");FileOutputStream fos = new FileOutputStream("E:\\1.rar");byte[] buf = new byte[1024];int len = 0;while((len=fis.read(buf))!=-1){fos.write(buf, 0, len);}fis.close();fos.close();

3.流转换

3.1 InputStreamReader类

字节流转为字符流：

InputStream in = System.in;InputStreamReader isr = new InputStreamReader(in);BufferedReader br = new BufferedReader(isr);//加字符缓冲区

可以简写如下：

BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));

3.2 OutStreamWriter类

字符流转为字节流：

                OutputStream out = System.out;OutputStreamWriter osw = new OutputStreamWriter(out);BufferedWriter bw = new BufferedWriter(osw);

简写：

BufferedWriter bufw = new BufferedWriter(new OutputStreamWriter(System.out));

所以从键盘输入数据然后从控制台输出，高效的话可以如下操作：

                BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));BufferedWriter bufw = new BufferedWriter(new OutputStreamWriter(System.out));String str = null;while((str=bufr.readLine())!=null){bufw.write(str.toUpperCase());bufw.newLine();bufw.flush();}bufr.close();bufw.close();

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