文件下载

package response;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

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 {

        //读取资源文件
        //String path = this.getServletContext().getRealPath("/download/1.jpg");
        String path = this.getServletContext().getRealPath("/download/图片.jpg");
        String filename = path.substring(path.lastIndexOf("\\")+1);
        //response.setHeader("content-disposition", "attachment;filename="+filename);//通知浏览器以下载方式打开

        //如果下载的文件是中文文件，这文件名需要经过url编码
        response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(filename, "UTF-8"));

        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){
                    e.printStackTrace();
                }
            }
            if(out != null){
                try{
                    out.close();
                }catch(Exception e){
                    e.printStackTrace();
                }
            }
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}