java 下载文件

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本文链接:https://blog.csdn.net/qq_29323645/article/details/103202799

 

下载的工具类完成

package com.geotmt.billingcenter.common.utils;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * @Description 文件下载类
 * @Author      yanghanwei
 * @Mail        yanghanwei@geotmt.com
 * @Date        10:31 2019-11-21
 * @Version     v1
 **/
public class DownFileUtils {

    /**
     * 以流的方式下载
     * @param path
     * @param response
     */
    public static void download(String path, HttpServletResponse response) {
        try {
            // path是指欲下载的文件的路径。
            File file = new File(path);
            // 取得文件名。
            String filename = file.getName();
            // 以流的形式下载文件。
            InputStream fis = new BufferedInputStream(new FileInputStream(path));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            // 清空response
            response.reset();
            // 设置response的Header
            response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
            response.addHeader("Content-Length", "" + file.length());
            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
            response.setContentType("multipart/form-data");
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    /**
     * 下载本地文件
     * @param response
     * @throws FileNotFoundException
     */
    public static void download(String fullPath, String fileName, HttpServletResponse response) throws FileNotFoundException {
        // 下载本地文件
        // 读到流中(文件的存放路径)
        InputStream inStream = new FileInputStream(fullPath);
        // 设置输出的格式
        response.reset();
        response.setContentType("bin");
        response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
        // 循环取出流中的数据
        byte[] b = new byte[100];
        int len;
        try {
            while ((len = inStream.read(b)) > 0) {
                response.getOutputStream().write(b, 0, len);
            }
            inStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 下载网络文件
     * @param Url
     * @throws MalformedURLException
     */
    public static void download(String Url) throws MalformedURLException {
        // 下载网络文件
        int bytesum = 0;
        int byteread = 0;

        URL url = new URL(Url);
        try {
            URLConnection conn = url.openConnection();
            InputStream inStream = conn.getInputStream();
            FileOutputStream fs = new FileOutputStream("c:/abc.gif");
            byte[] buffer = new byte[1204];
            while ((byteread = inStream.read(buffer)) != -1) {
                bytesum += byteread;
                System.out.println(bytesum);
                fs.write(buffer, 0, byteread);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    /**
     * 支持在线打开的方式
     * @param filePath
     * @param response
     * @param isOnLine
     */
    public static void download(String filePath, HttpServletResponse response, boolean isOnLine) {
        try{
            File f = new File(filePath);
            if (!f.exists()) {
                response.sendError(404, "File not found!");
                return;
            }
            BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
            byte[] buf = new byte[1024];
            int len = 0;

            // 非常重要
            response.reset();
            if (isOnLine) {
                // 在线打开方式
                URL u = new URL("file:///" + filePath);
                response.setContentType(u.openConnection().getContentType());
                response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
                // 文件名应该编码成UTF-8
            } else {
                // 纯下载方式
                response.setContentType("application/x-msdownload");
                response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
            }
            OutputStream out = response.getOutputStream();
            while ((len = br.read(buf)) > 0){
                out.write(buf, 0, len);
            }
            br.close();
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

 

简单使用


public void exportConsumeByMonthAndCust(String month, HttpServletResponse response) throws Exception{
             // 下载  zip 文件
            String outPath = "/data/app/aaa.zip";
            DownFileUtils.download(outPath, response);
            logger.info("============  下载成功!=============");
        }
    }

 

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