java实现从服务器下载文件到本地指定目录

2022-06-22 00:00:00 文件 指定 服务器
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
	     * 根据指定URL将文件下载到指定目标位置
	     * urlPath  下载路径
	     * downloadDir 文件存放目录
	     * @return
	     */
	    public String downloadFile(HttpServletRequest request,String urlPath){
	        File file = null;
	        try {
	            // 统一资源
	            if (StringUtils.isNotEmptyObject(PropertiesUtil.FILE_SAVE_PATH)) {
	//                urlPath = PropertiesUtil.FILE_SAVE_PATH + urlPath;
	                urlPath = "http://172.16.2.215:7777/" + urlPath;
	            }else{
	                urlPath =   request.getSession().getServletContext().getRealPath("")+urlPath;
	            }
	            // 统一资源
	            URL url = new URL(urlPath);
	            // 连接类的父类,抽象类
	            URLConnection urlConnection = url.openConnection();
	            // http的连接类
	            HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;
	            //设置超时
	            httpURLConnection.setConnectTimeout(1000*5);
	            //设置请求方式,默认是GET
	            httpURLConnection.setRequestMethod("GET");
	            // 设置字符编码
	            httpURLConnection.setRequestProperty("Charset", "UTF-8");
	            httpURLConnection.connect();
	            int fileLength = httpURLConnection.getContentLength();
	            BufferedInputStream bin = new BufferedInputStream(httpURLConnection.getInputStream());
	            String fileFullName = urlPath.substring(urlPath.lastIndexOf("/"));
	            // 指定存放位置
	            String path = "C:" + File.separatorChar + fileFullName;
	            file = new File(path);
	            // 校验文件夹目录是否存在,不存在就创建一个目录
	            if (!file.getParentFile().exists()) {
	                file.getParentFile().mkdirs();
	            }
	            OutputStream out = new FileOutputStream(file);
	            int size = 0;
	            int len = 0;
	            byte[] buf = new byte[2048];
	            while ((size = bin.read(buf)) != -1) {
	                len += size;
	                out.write(buf, 0, size);
	                System.out.println("下载了-------> " + len * 100 / fileLength + "%\n");
	            }
	            System.out.println("C:"+ File.separatorChar + urlPath.substring(urlPath.lastIndexOf("/")).split("/")[1]);
	            bin.close();
	            out.close();
	            System.out.println("文件下载成功!");
	        } catch (Exception e) {
	            System.out.println("文件下载失败!");
	            e.printStackTrace();
	        }finally {
	            return "C:"+ File.separatorChar + urlPath.substring(urlPath.lastIndexOf("/")).split("/")[1];
	        }
	    }
    原文作者:ernesto_ji
    原文地址: https://blog.csdn.net/qq_38407462/article/details/102856173
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