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