Java Springboot 根据图片链接生成图片下载链接 及 多个图片打包zip下载链接

现有一些图片在服务器上的链接，在浏览器中打开这些链接是直接显示在浏览器页面的形式。

现在需要生成这些图片的单独下载以及打包下载链接，即在浏览器中打开下载链接后弹出下载框提示下载。由于前端存在跨域问题，所以图片下载由后台接口完成。

首先编写文件下载工具类：

 1 import java.net.URL;
 2 import java.net.MalformedURLException; 3 import org.apache.commons.io.FileUtils; 4 5 public class FileDownloadUtil { 6 /** 7 * 下载文件---返回下载后的文件存储路径 8 * 9 * @param url 文件路径 10 * @param dir 目标存储目录 11 * @param fileName 存储文件名 12 * @return 13 */ 14 public static void downloadHttpUrl(String url, String dir, String fileName) throws BusinessException { 15 try { 16 URL httpurl = new URL(url); 17 File dirfile = new File(dir); 18 if (!dirfile.exists()) { 19  dirfile.mkdirs(); 20  } 21 FileUtils.copyURLToFile(httpurl, new File(dir+fileName)); 22 } catch (MalformedURLException e) { 23  e.printStackTrace(); 24 } catch (IOException e) { 25  e.printStackTrace();26  } 27  } 28 }

单张图片下载

Controller层接口：

 1 import org.apache.commons.lang.StringUtils;
 2 import java.io.*;
 3 
 4 
 5 protected HttpServletResponse response;
 6 
 7 /**
 8      * 单张图片下载
 9      *
10      * @param url 要下载的图片url
11      * @author: nemowang
12      */
13     @ApiImplicitParams({
14             @ApiImplicitParam(name = "url", value = "图片url", required = true, dataType = "String", paramType = "query"),
15     })
16     @ApiOperation(value = "单张图片下载", notes = "单张图片下载")
17     @RequestMapping(value = "/downloadPicture", method = RequestMethod.GET)
18     public void downloadPicture(String url) {
19         
20         // 拼接完整图片路径。这里填写图片链接
21         String urlPath = "";
22 
23         // 获取图片文件后缀名
24         String postfix = "." + StringUtils.substringAfterLast(url, ".");
25 
26         // 获取当前类的所在项目路径
27         File directory = new File("");
28         String courseFile;
29 
30         String srcPath;
31         File srcFile = null;
32         FileInputStream fileInputStream = null;
33         InputStream fis = null;
34         OutputStream out = null;
35         try {
36             courseFile = directory.getCanonicalPath();
37             String fileName = "//" + StringUtil.getUUID() + postfix;
38             // 下载文件
39             FileDownloadUtil.downloadHttpUrl(urlPath, courseFile, fileName);
40 
41             srcPath = courseFile + fileName;
42             srcFile = new File(srcPath);
43 
44             fileInputStream = new FileInputStream(srcPath);
45             fis = new BufferedInputStream(fileInputStream);
46             byte[] buffer = new byte[fis.available()];
47             fis.read(buffer);
48 
49             response.setContentType("application/octet-stream");
50             response.setHeader("Content-disposition", "attachment;filename=" + fileName);
51             out = response.getOutputStream();
52             out.write(buffer);
53             out.flush();
54             out.close();
55         } catch (Exception e) {
56             e.printStackTrace();
57         } finally {
58             try {
59                 if (fileInputStream != null) {
60                     fileInputStream.close();
61                 }
62                 if (fis != null) {
63                     fis.close();
64                 }
65                 if (out != null) {
66                     out.close();
67                 }
68             } catch (IOException e) {
69                 e.printStackTrace();
70             }
71         }
72 
73         // 删除中间文件
74         if (srcFile != null) {
75             System.out.println(WordExportUtil.deleteFile(srcFile));
76         }
77     }

因为是GET请求，所以直接拼接接口路由+参数，用浏览器打开就能弹出下载。

至此单张图片下载接口结束。

多张图片打包下载

Controller层接口：

 1 /**
 2      * 图片打包下载
 3      */
 4     @ApiImplicitParams({
 5             @ApiImplicitParam(name = "urls", value = "图片url列表", required = true, dataType = "List", paramType = "query"),
 6     })
 7     @ApiOperation(value = "图片打包下载", notes = "图片打包下载")
 8     @RequestMapping(value = "/downloadPictureList", method = RequestMethod.GET)
 9     public void downloadPictureList(List urls) {
10         List<String> fileNameList = new ArrayList<>();
11 
12         for (int i = 0; i < urls.size(); i++) {
13             // 获取文件名
14             fileNameList.add(StringUtils.substringAfterLast(urls.get(i), "/"));
15 
16             // 拼接完整图片路径
17             urls.set(i, DOMAIN + urls.get(i));
18         }
19 
20         // 获取当前类的所在项目路径
21         File directory = new File("");
22         String courseFile;
23 
24         String srcPath;
25         File srcFile = null;
26 
27         // 要打包的文件列表
28         List<File> fileList = new ArrayList<>();
29 
30         ZipOutputStream zos = null;
31         OutputStream out = null;
32         try {
33             courseFile = directory.getCanonicalPath();
34 
35             // 下载文件
36             for (int i = 0; i < urls.size(); i++) {
37                 String fileName = "//" + fileNameList.get(i);
38                 WordExportUtil.downloadHttpUrl(urls.get(i), courseFile, fileName);
39                 srcPath = courseFile + fileName;
40                 srcFile = new File(srcPath);
41                 fileList.add(srcFile);
42             }
43 
44 
45 
46             long start = System.currentTimeMillis();
47 
48             response.setContentType("application/x-zip-compressed");
49             response.setHeader("Content-disposition", "attachment;filename=" + StringUtil.getUUID() + ".zip");
50             out = response.getOutputStream();
51             zos = new ZipOutputStream(out);
52             for (File file : fileList) {
53                 byte[] buf = new byte[BUFFER_SIZE];
54                 zos.putNextEntry(new ZipEntry(file.getName()));
55                 int len;
56                 FileInputStream in = new FileInputStream(file);
57                 while ((len = in.read(buf)) != -1) {
58                     zos.write(buf, 0, len);
59                 }
60                 zos.closeEntry();
61                 in.close();
62             }
63             long end = System.currentTimeMillis();
64             System.out.println("压缩完成，耗时：" + (end - start) + " ms");
65 
66 
67             out.flush();
68         } catch (IOException e) {
69             e.printStackTrace();
70         } catch (Exception e) {
71                 throw new RuntimeException("zip error from ZipUtils", e);
72         } finally {
73             if (zos != null) {
74                 try {
75                     zos.close();
76                 } catch (IOException e) {
77                     e.printStackTrace();
78                 }
79             }
80             if (out != null) {
81                 try {
82                     zos.close();
83                 } catch (IOException e) {
84                     e.printStackTrace();
85                 }
86             }
87         }
88 
89         // 删除中间文件
90         if (fileList != null) {
91             for (File file : fileList) {
92                 System.out.println(WordExportUtil.deleteFile(file));
93             }
94         }
95     }

同样是GET请求，所以也是拼接接口路由+参数，用浏览器打开就能弹出下载。