package com.xia;

 import java.io.*;

 public class test2 {

     public static void main(String[] args) {

         //输出流

         try {

             FileOutputStream fos = new FileOutputStream("d:\\213.txt",true); //true 允许追加写入

             String str = "\n大家下午好!天气很不错!";  //  \n "转义字符"

             String str2 = "\n心情不错";

             fos.write(str.getBytes()); //覆盖写入

             fos.close();

             FileInputStream fis = new FileInputStream("d:\\213.txt");

             byte[] b = new byte[2048];

             int i = fis.read(b);

             String str1 = new String(b, 0 ,i);

             System.out.println("读取内容 = "+ str1);

             fis.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

     }

 }

 package com.xia;

 import java.io.*;

 public class test3 {

     public static void main(String[] args) {

         try {

             FileReader fr = new FileReader("d:\\213.txt");

             char[] c= new char[2048];

             int i = fr.read(c);

             String str = new String (c,0,i);

             System.out.println("读取内容 = " + str);

             fr.close();

         //写入

             FileWriter fw = new FileWriter("d:\\213.txt", true);

             fw.write("\n新追加的内容");

             fw.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

     }

 }