Detailed Explanation and Example of Operation File in Servlet

Detailed Explanation and Example of Operation File in Servlet

Because Servlet is originally a. Java file, the operation file in servlet and the operation file of ordinary java file are the same.

Read the main code of the file:

FileReader f=new FileReader("f:\\lissdy.txt");
BufferedReader bw=new BufferedReader(f);

Read out 1 row of data

String num=bw.readLine();

Note 1 Be sure to close the file stream

bw.close();

The method of writing files is similar, and the specific code is:

Read:

package com.lissdy;  
  
import java.io.BufferedReader;  
import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import java.io.*;  
@SuppressWarnings("serial")  
public class ReadFile extends HttpServlet{  
  public void doGet(HttpServletRequest req,HttpServletResponse res)  
  {  
    try {  
    res.setContentType("text/html;charset=gbk");  
    PrintWriter pw=res.getWriter();  
    FileReader f=new FileReader("d:\\lissdy.txt");  
    BufferedReader bw=new BufferedReader(f);  
    String num=bw.readLine();  
    bw.close();  
    pw.println(" The data read from the file is: "+num);  
  } catch (IOException e) {  
    // TODO Auto-generated catch block  
    e.printStackTrace();  
  }  
  }  
}  

Write:

package com.lissdy;  
  
import java.io.IOException;  
import java.io.PrintWriter;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import java.io.*;  
@SuppressWarnings("serial")  
public class WriteFile extends HttpServlet{  
  public void doGet(HttpServletRequest req,HttpServletResponse res)  
  {  
    try {  
    res.setContentType("text/html;charset=gbk");  
    PrintWriter pw=res.getWriter();  
    // Flow from memory to disk as write ( Output stream )  
    // Flows from disk files to memory for reading ( Input stream )  
    FileWriter f=new FileWriter("d:\\lissdy.txt");  
    BufferedWriter bw=new BufferedWriter(f);  
    bw.write(" Try 1 Try how to write the file ");  
    pw.println(" Write data to a file ");  
    bw.close();  
  } catch (IOException e) {  
    // TODO Auto-generated catch block  
    e.printStackTrace();  
  }  
  }  
}  

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