实现文件下载的Java代码

//这是实现下载类（servlet），具体思路代码如下：
//也可连接数据库
package com.message;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class FileDownServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=GBK";

//Initialize global variables
public void init() throws ServletException {
}

//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
response.setContentType(CONTENT_TYPE);
//得到下载文件的名字
//String filename=request.getParameter("filename");

//解决中文乱码问题
String filename=new String(request.getParameter("filename").getBytes("iso-8859-1"),"gbk");

//创建file对象
File file=new File("F:\\book\\WebRoot\\"+filename);

//设置response的编码方式
response.setContentType("application/x-msdownload");

//写明要下载的文件的大小
response.setContentLength((int)file.length());

//设置附加文件名
// response.setHeader("Content-Disposition","attachment;filename="+filename);

//解决中文乱码
response.setHeader("Content-Disposition","attachment;filename="+new String

(filename.getBytes("gbk"),"iso-8859-1"));

//读出文件到i/o流
FileInputStream fis=new FileInputStream(file);
BufferedInputStream buff=new BufferedInputStream(fis);

byte [] b=new byte[1024];//相当于我们的缓存

long k=0;//该值用于计算当前实际下载了多少字节

//从response对象中得到输出流,准备下载

OutputStream myout=response.getOutputStream();

//开始循环下载

while(k

int j=buff.read(b,0,1024);
k+=j;

//将b中的数据写到客户端的内存
myout.write(b,0,j);

}

//将写入到客户端的内存的数据,刷新到磁盘
myout.flush();

}

//Process the HTTP Post request
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
doGet(request, response);
}

//Clean up resources
public void destroy() {
}
}

//这是javabean写法 ，主要是实现和数据库连接的，如果没有连接数据库，就可直接不要这
package com;

public class MessageBean {
private String Message;

public String getMessage() {
return Message;
}

public void setMessage(String message) {
Message = message;
}
}