servlet中操作文件详解及实例
因为servlet本来就是一个.java文件,因此servlet中操作文件和普通java文件操作文件是一样的。
读取文件主要代码:
filereader f=new filereader("f:\lissdy.txt");
bufferedreader bw=new bufferedreader(f);
读出一行数据
string num=bw.readline();
注意一定要关闭文件流
bw.close();
写文件的方法与之类似,具体代码为:
读取:
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("从文件中读取的数据是:"+num);
} catch (ioexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
}
写入:
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();
//从内存到磁盘流动为写(输出流)
//从磁盘文件到内存流动为读(输入流)
filewriter f=new filewriter("d:\lissdy.txt");
bufferedwriter bw=new bufferedwriter(f);
bw.write("试一试文件怎么写");
pw.println("向文件写入数据");
bw.close();
} catch (ioexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
}
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