FileDownload.java文件恢复

shandan-common/src/main/java/com/keyware/shandan/common/util/FileDownload.java

@@ -1,5 +1,7 @@
 package com.keyware.shandan.common.util;
 
+import org.springframework.util.Assert;
+
 import javax.servlet.http.HttpServletResponse;
 import java.io.BufferedInputStream;
 import java.io.File;
@@ -8,43 +10,80 @@ import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 
+/**
+ * 文件下載工具类
+ */
 public class FileDownload {
-    public static String download(HttpServletResponse response, File file, boolean deleteFile) {
-        return download(response, file, file.getName(), deleteFile);
+    /**
+     * @param response HttpServletResponse
+     * @param file     File
+     * @return 结果
+     */
+    public static String download(HttpServletResponse response, File file) {
+        return download(response, file, null, false);
     }
 
+    /**
+     * @param response HttpServletResponse
+     * @param file     File
+     * @param fileName 输出的文件名
+     * @return 结果
+     */
     public static String download(HttpServletResponse response, File file, String fileName) {
         return download(response, file, fileName, false);
     }
 
-    public static String download(HttpServletResponse response, File file, String fileName, boolean deleteFile) {
-        try (BufferedInputStream bis = new BufferedInputStream(Files.newInputStream(file.toPath()));
-             OutputStream out = response.getOutputStream()) {
-            response.setCharacterEncoding("UTF-8");
+    /**
+     * @param response HttpServletResponse
+     * @param file     File
+     * @param delete   下载完成后是否删除源文件
+     * @return 结果
+     */
+    public static String download(HttpServletResponse response, File file, boolean delete) {
+        return download(response, file, null, delete);
+    }
+
+    /**
+     * @param response HttpServletResponse
+     * @param file     File
+     * @param fileName 输出的文件名称
+     * @param delete   下载完成后是否删除源文件
+     * @return 结果
+     */
+    public static String download(HttpServletResponse response, File file, String fileName, boolean delete) {
+        Assert.notNull(response, "response is null.");
+        Assert.notNull(file, "file is null.");
+        Assert.isTrue(file.exists(), "没有在文件系统中找到该文件.");
+
+        response.reset();
         response.setContentType("application/octet-stream");
+        response.setCharacterEncoding("utf-8");
+        response.setContentLength((int) file.length());
+
+        if (!StringUtils.hasText(fileName)) {
+            fileName = file.getName();
+        }
+
+        // 解决下载文件时文件名乱码问题
         byte[] fileNameBytes = fileName.getBytes(StandardCharsets.UTF_8);
-            response.setHeader("Content-disposition", "attachment;filename=" + new String(fileNameBytes, 0, fileNameBytes.length, StandardCharsets.ISO_8859_1));
+        String outputName = new String(fileNameBytes, 0, fileNameBytes.length, StandardCharsets.ISO_8859_1);
+        response.setHeader("Content-Disposition", "attachment;filename=" + outputName);
 
-            byte[] buffer = new byte[1024];  // 缓冲区
-            int bytesToRead = 0;
-            // 通过循环将读入的Word文件的内容输出到浏览器中
-            while ((bytesToRead = bis.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesToRead);
-                out.flush();
+        try (OutputStream os = response.getOutputStream();
+             BufferedInputStream bis = new BufferedInputStream(Files.newInputStream(file.toPath()))) {
+            byte[] buff = new byte[1024];
+            int i = 0;
+            while ((i = bis.read(buff)) != -1) {
+                os.write(buff, 0, i);
+                os.flush();
             }
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            return "下载过程出现错误，文件流读取异常！";
         } finally {
-            if (deleteFile) {
-                try {
-                    Thread.sleep(100);
-                } catch (InterruptedException ignored) {
-                }
+            if (delete) {
                 file.deleteOnExit();
             }
-
         }
-
-        return "download success";
+        return "下载完成";
     }
 }