Java:IO流的一些典型例子

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1. 文本文件复制 TestCopyText.java

/**用字符流复制txt文件*/import java.io.*;class TestCopyText{public static void main(String[] args) throws Exception{//创建一个读取流，与磁盘源文件关联FileReader fr = new FileReader("E:\\《基督山伯爵》.txt");BufferedReader in = new BufferedReader(new FileReader(fr);//创建一个写入流，与磁盘目的文件关联FileWriter fw = new FileWriter("D:\\基督山伯爵.txt");BufferedWriter out = new BufferedWriter(fw);//1.读取一行保存在字符串中String line = null;while((line = in.readLine()) != null)  //readLine不包含终止符{out.write(line, 0, line.length());out.newLine();//换行out.flush();}in.close();out.close();//2.读取一个字符/* int ch = 0;while((ch = in.read()) != -1){out.write(ch);}in.close();out.close(); *///3.读取到一个字符数组中/* char[] buf = new char[1024];int len = 0;while((len = in.read(buf)) != -1){out.write(buf, 0, len);}in.close();out.close(); */}}

2. 图片复制 TestCopyPic.java

/**用字节流复制图片*/import java.io.*;class TestCopyPic{public static void main(String[] args) throws Exception{//创建读取流关联源文件FileInputStream fis = new FileInputStream("D:\\dsp.jpg.");BufferedInputStream in = new BufferedInputStream(fis);//创建写入流关联目的文件FileOutputStream fos = new FileOutputStream("E:\\dsp.jpg");BufferedOutputStream out = new BufferedOutputStream(fos);int len = 0;byte[] buf = new byte[1024];while((len = in.read(buf)) != -1){out.write(buf, 0, len);out.flush();}in.close();out.close();}}

3. 把从键盘录入的字符保存在文件中 TestKeyToFile.java

/**把从键盘录入的字符保存在文件中，运用转换流*/import java.io.*;class TestKeyToFile{public static void main(String[] args) throws Exception{InputStream is = System.in;   //获取键盘读取流InputStreamReader isr = new InputStreamReader(is);  //通过转换流把字节流流转换成字符流BufferedReader bufr = new BufferedReader(isr);  //字符流加上缓冲区//创建写入流关联目标文件FileWriter fw = new FileWriter("D:\\key.txt");BufferedWriter bufw = new BufferedWriter(fw);String line = null;while((line = bufr.readLine()) != null){if(line.equals("over"))break;bufw.write(line, 0, line.length());bufw.flush();}bufr.close();bufw.close();}}

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