读/写文件操作

1.JavaEE(先在文件中中写入内容,再读取文件中的内容)

内存数据-->磁盘文件(写入,输出)

磁盘文件-->内存数据(读入,输入)

 1 package com.tsinghua;
 2 
 3 import javax.servlet.http.*;
 4 import java.io.*;
 5 
 6 public class File extends HttpServlet {
 7     public void doGet(HttpServletRequest req,HttpServletResponse res) {
 8         try {
 9             res.setContentType("text/plain;charset=utf8");
10             PrintWriter pw = res.getWriter();
11             //文件若不存在,则自动生成该文件
12             FileWriter fw = new FileWriter("f://writeFile.txt");
13             BufferedWriter bw = new BufferedWriter(fw);
14             bw.write("你好,姜昇润");
15             bw.close();
16             
17             FileReader fr = new FileReader("f://writeFile.txt");
18             BufferedReader br = new BufferedReader(fr);
19             //读一行数据
20             String content = br.readLine();
21             br.close();
22             pw.println(content);
23                 
24         }catch(Exception ex) {
25             ex.printStackTrace();    
26         }
27     }
28     public void doPost(HttpServletRequest req,HttpServletResponse res) {
29         this.doGet(req,res);    
30     }    
31 }

File.java