Java文件下载工具类 （四种方式）

 

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1	FileUtils.java

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package com.cmbchina.ccd.itpm.project.util;   import org.slf4j.Logger;   import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.URL; import java.net.URLConnection; import java.net.URLEncoder; import java.nio.charset.StandardCharsets;   import static org.slf4j.LoggerFactory.getLogger;   /**  * @ClassName FileUtils  * @Description 文件下载  * @Author Sue  * @Create 2020/4/16 9:00  **/ public class FileUtils {       private static final Logger logger = getLogger(FileUtils.class);       public static void download(HttpServletResponse response, String filePath, String encode) {         response.setContentType("text/html;charset=" + encode);         String downLoadPath = filePath;         File file = new File(downLoadPath);         try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(downLoadPath)); BufferedOutputStream bos = new BufferedOutputStream(                 response.getOutputStream())) {             long fileLength = file.length();             String fileName = file.getName();             response.setContentType("application/x-msdownload;");             response.setHeader("Content-disposition", "attachment; filename=" + new String(fileName.getBytes(encode), StandardCharsets.UTF_8));             response.setHeader("Content-Length", String.valueOf(fileLength));             byte[] buff = new byte[2048];             int bytesRead;             while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {                 bos.write(buff, 0, bytesRead);             }         } catch (Exception e) {             logger.error(e.getMessage());         }     }       /**      * 以流的方式下载      *      * @param path      * @param response      * @return      */     public HttpServletResponse 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();             // 取得文件的后缀名。             String ext = filename.substring(".".lastIndexOf(filename) + 1).toUpperCase();             // 以流的形式下载文件。             byte[] buffer;             try (InputStream fis = new BufferedInputStream(new FileInputStream(path))) {                 buffer = new byte[fis.available()];                 fis.read(buffer);             }             // 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("application/octet-stream");             toClient.write(buffer);             toClient.flush();             toClient.close();         } catch (IOException ex) {             logger.error("{}", ex);         }         return response;     }       /**      * 下载本地文件      *      * @param response      * @throws FileNotFoundException      */     public void downloadLocal(HttpServletResponse response) throws IOException {         // 下载本地文件         // 文件的默认保存名         String fileName = "Operator.doc";         // 读到流中         // 文件的存放路径         try (InputStream inStream = new FileInputStream("c:/Operator.doc")) {             // 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);                 }             } catch (IOException e) {                 logger.error("{}", e);             }         }       }       /**      * 下载网络文件      *      * @throws IOException      */     public void downloadNet() throws IOException {         // 下载网络文件         int bytesum = 0;         int byteread;           URL url = new URL("windine.blogdriver.com/logo.gif");           URLConnection conn = url.openConnection();         try (InputStream inStream = conn.getInputStream(); FileOutputStream fs = new FileOutputStream("c:/abc.gif")) {             byte[] buffer = new byte[1204];             while ((byteread = inStream.read(buffer)) != -1) {                 bytesum += byteread;                 fs.write(buffer, 0, byteread);             }         }     }         public void downLoadIsOnLine(String fileName, HttpServletRequest request, HttpServletResponse response, boolean isOnLine) throws IOException {         String absolutePath = fileName;         File f = new File(absolutePath);         if (!f.exists()) {             response.sendError(404, "File not found!");             return;         }         //解决中文乱码         String userAgent = request.getHeader("user-agent").toLowerCase();         fileName = f.getName();         String downloadFileName;           if (userAgent.contains("msie") || userAgent.contains("like gecko")) {             downloadFileName = URLEncoder.encode((fileName), "UTF-8");         } else {             downloadFileName = new String((fileName).getBytes(StandardCharsets.UTF_8), "iso-8859-1");         }         byte[] buf = new byte[1024];         int len = 0;           response.reset(); // 非常重要         // 在线打开方式         if (isOnLine) {             URL u = new URL("file:///" + absolutePath);             response.setContentType(u.openConnection().getContentType());             response.setHeader("Content-Disposition", "inline; filename=" + downloadFileName);             // 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=" + downloadFileName);         }           try (BufferedInputStream br = new BufferedInputStream(new FileInputStream(f)); OutputStream out = response.getOutputStream()) {               while ((len = br.read(buf)) > 0) {                 out.write(buf, 0, len);             }         }     }     }