计算机那些事Java

Tip: Upload Multiple Files with Jersey

这篇文章将简单介绍一下如何用Jersey（DropWizard）在一次Request中接受多个文件。其实Google一下，SO上会有很多回答，只是在这边献丑一下。

1. 添加必要的依赖

因为要上传文件，所以这个依赖是必须的

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<dependency>
   <groupId>org.glassfish.jersey.media</groupId>
   <artifactId>jersey-media-multipart</artifactId>
   <version>{latest-version}</version>
</dependency>

2. 在配置文件中注册

查看Github源文件：https://github.com/zhouhao/RESTful-Examples/blob/master/src/main/java/me/hzhou/demo/App.java

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@Override
public void run(Configure configuration, Environment environment) {
   // more code
   environment.jersey().register(MultiPartFeature.class);
}

3. 添加Resource

以下方法来自SO。查看demo源码

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@Path("/upload")
@POST
@Consumes(MediaType.MULTIPART_FORM_DATA)
@Produces(MediaType.APPLICATION_JSON)
public Response upload(FormDataMultiPart form) {
   List<FormDataBodyPart> parts = form.getFields("file");
   List<String> result = new ArrayList<String>();
   for (FormDataBodyPart part : parts) {
       FormDataContentDisposition file = part.getFormDataContentDisposition();
       InputStream fileInputStream = part.getValueAs(InputStream.class);

       String filePath = "/tmp/" + file.getFileName();
       // save the file to the server
       saveFile(fileInputStream, filePath);
       String output = "File saved to server location using FormDataMultiPart : " + filePath;
       result.add(output);
   }
   return Response.ok(result).build();
}

// save uploaded file to a defined location on the server
private void saveFile(InputStream uploadedInputStream, String serverLocation) {
   try {
       OutputStream outputStream = new FileOutputStream(new File(serverLocation));
       int read = 0;
       byte[] bytes = new byte[1024];
       while ((read = uploadedInputStream.read(bytes)) != -1) {
           outputStream.write(bytes, 0, read);
       }
       outputStream.flush();
       outputStream.close();
       uploadedInputStream.close();

   } catch (IOException e) {
       e.printStackTrace();
   }
}

4. 简单客户端测试

启动DropWizard线程之后，直接在浏览器打开这个文件即可进行测试

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Files Upload</title>
</head>
<body>
<form name="formtest" action="http://127.0.0.1:8080/upload" method="POST" enctype="multipart/form-data">
    <input type="file" name="file" value="" />
    <input type="file" name="file" value="" />
    <input type="submit" value="submit" />
</form>
</body>
</html>

5. All set, have fun!!!