response实现文件下载

package cn.itcast.response;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.URLEncoder;

import java.nio.file.Path;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

//文件下载

public class ResponseDemo3 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String path = this.getServletContext().getRealPath("/download/徐.jpg");

String filename = path.substring(path.lastIndexOf("\\")+1);

//如果下载文件是中文文件，则文件名需要经过url编码

// response.setHeader("content-disposition","attachment;filename"+URLEncoder.encode(filename,"UTF-8"));

response.setHeader("content-disposition", "attachment;filename"+filename);

InputStream in = null;

OutputStream out = null;

try {

in = new FileInputStream(path);

int len = 0;

byte buffer[] = new byte[1024];

out = response.getOutputStream();

while((len = in.read(buffer)) >0){

out.write(buffer,0,len);

}

} finally{

if(in != null){

try {

in.close();

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

}

}