Java实现上传下载

一、上传

二、下载

 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URLEncoder;

 import javax.servlet.http.HttpServletResponse;

 public class DownloadFileUtil {
     /**
      * 弹窗下载
      * @param response
      * @param filePath
      *            文件所在路径
      * @param fileName
      *            文件名
      */
     public void downFile(HttpServletResponse response, String filePath,
             String fileName) {
         try {
             String path = filePath + fileName;
             File file = new File(path);
             if (file.exists()) {
                 InputStream ins = new FileInputStream(path);
                 BufferedInputStream bins = new BufferedInputStream(ins);// 放到缓冲流里面
                 OutputStream outs = response.getOutputStream();// 获取文件输出IO流
                 BufferedOutputStream bouts = new BufferedOutputStream(outs);
                 response.setContentType("application/x-download");// 设置response内容的类型
                 response.setHeader("Content-disposition","attachment;filename="
                                 + URLEncoder.encode(fileName, "GBK"));// 设置头部信息
                 int bytesRead = 0;
                 byte[] buffer = new byte[8192];
                 // 开始向网络传输文件流
                 while ((bytesRead = bins.read(buffer, 0, 8192)) != -1) {
                     bouts.write(buffer, 0, bytesRead);
                 }
                 bouts.flush();// 这里一定要调用flush()方法
                 ins.close();
                 bins.close();
                 outs.close();
                 bouts.close();
             }
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
 }

有一篇不错的文章：http://blog.csdn.net/chow__zh/article/details/9288793#comments