步骤
<!DOCTYPE html>
<!--
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<html>
<head>
<title>计算机网络课程设计</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<img src="/theCourseDesign/downloadServlet?filename=1.jpg" style="width: 502.4px;height: 276.8px" />
<br>
<a href="/theCourseDesign/downloadServlet?filename=1.jpg">点击下载</a>
<br>
</body>
</html>
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package download;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author 郑佳杰
*/
public class DownloadServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获取请求参数，文件名称
String filename=request.getParameter("filename");
//使用字节输出流加载文件进内存
//找到文件服务器路径
ServletContext servletContext=this.getServletContext();
String realpath = servletContext.getRealPath("/Testpicture/"+filename);
//使用字节流关联
FileInputStream fis=new FileInputStream(realpath);
//设置response的响应头
String mimeType=servletContext.getMimeType(filename);
response.setHeader("content-type", mimeType);
response.setHeader("content-disposition", "attachment;filename="+filename);
//将输入流的数据写到输出流
ServletOutputStream sos=response.getOutputStream();
byte[] buff=new byte[1024*8];
int len=0;
while((len=fis.read(buff))!=-1){
sos.write(buff, 0, len);
}
fis.close();
sos.close();
}
public String getServletInfo() {
return "Short description";
}
}
