最近做了一次下载网络图片然后上传到fastDFS的任务。碰到了个别小问题现在记录一下。
主要思路
- 下载图片，然后，生成临时文件
- 得到临时文件生成的文件流
- 上传该文件流到fastDFS。
系统分析
- 网络图片下载
public static File downloadFromUrl(String urlStr){
//获取URL对象
URL url = null;
HttpURLConnection conn = null;
File file = null;
try {
url = new URL(urlStr);
//获取连接
conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(6000);
//设置超时时间是3秒
conn.setReadTimeout(6000);
//防止屏蔽程序抓取而返回403错误
conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.19 Safari/537.36");
//得到临时文件
file = getTemplateFile(conn.getInputStream());
} catch (MalformedURLException e) {
log.error("图片下载出现异常={}", e.getMessage());
throw new DownloadException("图片下载失败");
} catch (Exception e) {
log.error("图片下载出现异常={}", e.getMessage());
throw new DownloadException("图片下载失败");
} finally {
//关闭连接
if (conn != null) {
conn.disconnect();
}
}
return file;
}此处得到一个输入流之后生成了一个临时文件，至于为啥要生成临时文件，主要的原因是如果直接将下载得到的输入流上传到fastDFS 上会导致上传之后的图片显示不全。故，做了如下如下处理。
生成临时文件：
/**
* 获取模板文件--获取到的文件为临时文件，用完后需要手动删除
*
* @param inputStream
* @return 模板文件
* @throws Exception 异常抛出
*/
public static File getTemplateFile(InputStream inputStream) throws Exception {
File file = File.createTempFile("temp_image", null);
inputStreamToFile(inputStream, file);
return file;
}
/**
* InputStream 转file
*
* @param ins 输入流
* @param file 目标文件
*/
public static void inputStreamToFile(InputStream ins, File file) {
try {
OutputStream os = new FileOutputStream(file);
try {
int bytesRead = 0;
byte[] buffer = new byte[8192];
while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
os.write(buffer, 0, bytesRead);
}
os.flush();
} finally {
if (os != null) {
os.close();
}
if (ins != null) {
ins.close();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
- 图片上传
@Override
public String download2UploadImg(String oldUrl) throws Exception {
//1.下载图片
File tempFile = null;
InputStream is = null;
String newPic;
try {
tempFile = ImageUtil.downloadFromUrl(oldUrl);
String fileName;
if (oldUrl.contains(SPECIAL_SIGN)) {
fileName = oldUrl.substring(oldUrl.lastIndexOf("/") + 1, oldUrl.indexOf(SPECIAL_SIGN));
} else {
fileName = oldUrl.substring(oldUrl.lastIndexOf("/") + 1);
}
//校验格式
String suffix = fileName.substring(fileName.indexOf("."));
if (!ImageContentType.toMap().containsKey(suffix)) {
log.info("文件格式不对，该格式为={}", suffix);
throw new ImageException("图片格式不对");
}
is = new FileInputStream(tempFile);
if (tempFile == null || is == null || is.available() <= 0) {
log.info("图片为空");
throw new ImageException("图片为空");
}
//2.上传图片
newPic = FastDfsUtil.uploadFile(is, fileName);
} finally {
//手动删除临时文件
if (is != null) {
try {
is.close();
} catch (IOException e) {
throw new IOException("文件流关闭失败");
}
}
if (tempFile != null) {
tempFile.delete();
}
}
log.info("上传完之后新图片地址="+(fastdfs_url + newPic));
return fastdfs_url + newPic;
}具体的上传方式参见：上传图片到fastDFS
3. 测试方法
@Test
public void testDownload2Upload() throws Exception {
//1.图片正常下载上传
String oldUrl = "http://img.okwuyou.com/shop/store/goods/1/2017/05/16/1_05482671770179845.jpg";
Assert.assertNotNull(okwuyouSynItemService.download2UploadImg(oldUrl));
//2.图片为空
String oldUrl1 = "http://img.okwuyou.com/shop/store/goods/1/2018/01/25/48_05701903155753607.jpg";
try {
okwuyouSynItemService.download2UploadImg(oldUrl1);
} catch (Exception e) {
Assert.assertTrue(e instanceof DownloadException);
}
//3.图片路径失效
String oldUrl2 = "http://192.168.210.110/group1/M00/34/0A/wKjScFsovu6ACg1VAADTHQHL6FA290.jpg";
try {
okwuyouSynItemService.download2UploadImg(oldUrl2);
} catch (Exception e) {
Assert.assertTrue(e instanceof DownloadException);
}
//4.图片格式不对
String oldUrl3 = "https://github.com/XWxiaowei/JavaWeb/blob/master/jackson-demo/pom.xml";
try {
okwuyouSynItemService.download2UploadImg(oldUrl3);
} catch (Exception e) {
Assert.assertTrue(e instanceof ImageException);
}
}
@Test
public void testDeleteFile() {
//5.临时文件是否删除
// 1.获取临时文件的地址
String tempPath = System.getProperty("java.io.tmpdir") + File.separator;
System.out.println("临时文件的目录是=" + tempPath);
// 2.匹配临时文件
List<String> fileNameList = getAllFile(tempPath, false);
if (!CollectionUtils.isEmpty(fileNameList)) {
int i = 0;
for (String s : fileNameList) {
if (s.contains("temp_image")) {
i++;
System.out.println("临时文件未删除" + i);
}
}
}
}
/**
* 获取路径下的所有文件/文件夹
* @param directoryPath 需要遍历的文件夹路径
* @param isAddDirectory 是否将子文件夹的路径也添加到list集合中
* @return
*/
public static List<String> getAllFile(String directoryPath,boolean isAddDirectory) {
List<String> list = new ArrayList<String>();
File baseFile = new File(directoryPath);
if (baseFile.isFile() || !baseFile.exists()) {
return list;
}
File[] files = baseFile.listFiles();
for (File file : files) {
if (file.isDirectory()) {
if(isAddDirectory){
list.add(file.getAbsolutePath());
}
list.addAll(getAllFile(file.getAbsolutePath(),isAddDirectory));
} else {
list.add(file.getAbsolutePath());
}
}
return list;
}