BufferedReader
InputStreamReader
FileInputStream
DataInputStream
OutputStreamWriter
1 这几个类有什么区别呢，分别怎么用呢，
2 现我想向 D:\demosun\demosu.txt 这文件中写入一行文字，怎么实现呢
3 现我想把 D:\demosun\demosu.txt 这文件中的内容读出来 怎么实现呢
thanks
------解决方案--------------------
具体怎么用你好好去看看API手册，帮你写了个例子。
- Java code
package com.study.io;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class ReadAndWriteFile { public static void main(String[] args) { //写文件 writeFile("文件路径", "文件内容"); //读文件 readFile("文件路径"); } public static void readFile(String path){ BufferedReader reader = null; try { reader = new BufferedReader(new FileReader("")); while(true){ String line = reader.readLine(); if(line == null){ break; } System.out.println(line + "\n"); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally{ if(reader != null){ try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } } public static void writeFile(String path, String content){ BufferedWriter writer = null; try { writer = new BufferedWriter(new FileWriter("")); writer.write(content); writer.flush(); } catch (IOException e) { e.printStackTrace(); } finally{ if(writer != null){ try { writer.close(); } catch (IOException e) { e.printStackTrace(); } } } }}
------解决方案--------------------
原理：http://www.iteye.com/topic/313635
实践：http://www.cnblogs.com/rollenholt/archive/2011/09/11/2173787.html