文件下载
使用代码下载
1 package cn.servlet; 2 3 import java.io.FileInputStream; 4 import java.io.IOException; 5 import java.io.InputStream; 6 import java.io.OutputStream; 7 import java.net.URLEncoder; 8 9 import javax.servlet.ServletException; 10 import javax.servlet.http.HttpServlet; 11 import javax.servlet.http.HttpServletRequest; 12 import javax.servlet.http.HttpServletResponse; 13 14 public class DownServlet extends HttpServlet { 15 @Override 16 public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 17 System.err.println("判断用户的积分信息....."); 18 //获取真实的文件 19 String path = getServletContext().getRealPath("/files/cos.jar"); 20 //获取这个文件的io 21 InputStream in = 22 new FileInputStream(path); 23 //设置响应的头信息 24 //如果希望将下载的文件修改成中文名，则必须要对中文名称进行编码 25 String name = "下载的文件.jar"; 26 name = URLEncoder.encode(name,"UTF-8"); 27 resp.setHeader("Content-Disposition","attachment;filename="+name); 28 resp.setContentType("application/force-download"); 29 30 byte[] bs = new byte[1024]; 31 OutputStream out = 32 resp.getOutputStream(); 33 int len = 0; 34 while((len=in.read(bs))!=-1){ 35 out.write(bs,0,len); 36 } 37 in.close(); 38 out.close(); 39 } 40 } 41 42 <br> 43 <a href="<c:url value='/files/cos.jar'/>">下载</a> 44 <br> 45 <a href="<c:url value='/down'/>">Download</a>
自己使用urlconnection实现下载
1 package cn.client; 2 3 import java.io.FileOutputStream; 4 import java.io.InputStream; 5 import java.io.OutputStream; 6 import java.net.HttpURLConnection; 7 import java.net.URL; 8 public class Client { 9 public static void main(String[] args) throws Exception { 10 //1:声明url地址 11 URL url = new URL("http://localhost:8080/20151116/files/cos.jar"); 12 HttpURLConnection con = 13 (HttpURLConnection) url.openConnection(); 14 con.setRequestMethod("GET"); 15 con.setDoOutput(true); 16 con.setDoInput(true); 17 con.setConnectTimeout(3000); 18 con.connect(); 19 20 //获取连接的状态 21 int code = con.getResponseCode(); 22 if(code==200){ 23 InputStream in = 24 con.getInputStream(); 25 byte[] bs = new byte[1024]; 26 int len = 0; 27 OutputStream out = new FileOutputStream("d:/a/a.jar"); 28 while((len=in.read(bs))!=-1){ 29 out.write(bs, 0, len); 30 } 31 out.close(); 32 in.close(); 33 } 34 con.disconnect(); 35 } 36 }
