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>2.22.2</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!!!