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。
正文到此结束
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