通过request实现文件下载

//通过response实现文件下载import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.PrintWriter;import java.io.UnsupportedEncodingException;import java.net.URLEncoder;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;//public class ResponseDemo3 extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse response)throws ServletException, IOException {test1(response);}private void test2(HttpServletResponse response)throws FileNotFoundException, IOException {String path=this.getServletContext().getRealPath("/download/新图片.jpg");//C:\apache-tomcat-7.0.22\webapps\day06\download\新图片.jspString filename=path.substring(path.lastIndexOf("\\")+1);InputStream in=null;OutputStream out=null;//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"));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){e.printStackTrace();}}}}private void test1(HttpServletResponse response)throws FileNotFoundException, IOException {String path=this.getServletContext().getRealPath("/download/new.jpg");//C:\apache-tomcat-7.0.22\webapps\day06\download\new.jspString filename=path.substring(path.lastIndexOf("\\")+1);InputStream in=null;OutputStream out=null;response.setHeader("content-disposition", "attachment;filename="+filename);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){e.printStackTrace();}}}}}