# RESTEasy 文件上传 - `HttpClient`示例 > 原文： [https://howtodoinjava.com/resteasy/jax-rs-resteasy-file-upload-httpclient-example/](https://howtodoinjava.com/resteasy/jax-rs-resteasy-file-upload-httpclient-example/) 在以前的文章中，我们了解了[**文件下载**](//howtodoinjava.com/resteasy/resteasy-file-download-example/ "RESTEasy + File download example")以及构建 [**RESTful 客户端**](//howtodoinjava.com/apache-commons/jax-rs-restful-client-using-apache-httpclient/ "JAX-RS RESTful client using apache httpclient")的知识。 现在，让我们继续前进。 在这篇文章中，我将提供使用 jax-rs resteasy 上传文件的示例代码。 要上传文件，将使用[**`httpclient`**](https://hc.apache.org/httpclient-3.x/ "http client")库代替 HTML 表单。 我正在使用[**`MultipartFormDataInput`**](http://docs.jboss.org/resteasy/docs/1.2.GA/javadocs/org/jboss/resteasy/plugins/providers/multipart/MultipartFormDataInput.html "MultipartFormDataInput")类，它是`resteasy-multipart`插件的一部分。 **1）更新项目的 Maven 依赖项** 在 maven 依赖项下添加/更新，以添加对项目中多部分文件上传的支持。 ```java <!-- core library --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxrs</artifactId> <version>2.3.1.GA</version> </dependency> <dependency> <groupId>net.sf.scannotation</groupId> <artifactId>scannotation</artifactId> <version>1.0.2</version> </dependency> <!-- JAXB provider --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxb-provider</artifactId> <version>2.3.1.GA</version> </dependency> <!-- Multipart support --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-multipart-provider</artifactId> <version>2.3.1.GA</version> </dependency> <!-- For better I/O control --> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.0.1</version> </dependency> ``` 还要添加下图给出的 jar 文件。 需要使用它们来构建用于文件上传示例的客户端代码。  HTTP 客户端 jar 文件 **2）准备将要在客户端上载文件的 http 客户端** ```java package com.howtodoinjava.client.upload; import java.io.File; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.mime.MultipartEntity; import org.apache.http.entity.mime.content.FileBody; import org.apache.http.entity.mime.content.StringBody; import org.apache.http.impl.client.DefaultHttpClient; public class DemoFileUploader { public static void main(String args[]) throws Exception { DemoFileUploader fileUpload = new DemoFileUploader () ; File file = new File("C:/Lokesh/Setup/workspace/RESTfulDemoApplication/target/classes/Tulips.jpg") ; //Upload the file fileUpload.executeMultiPartRequest("http://localhost:8080/RESTfulDemoApplication/user-management/image-upload", file, file.getName(), "File Uploaded :: Tulips.jpg") ; } public void executeMultiPartRequest(String urlString, File file, String fileName, String fileDescription) throws Exception { HttpClient client = new DefaultHttpClient() ; HttpPost postRequest = new HttpPost (urlString) ; try { //Set various attributes MultipartEntity multiPartEntity = new MultipartEntity () ; multiPartEntity.addPart("fileDescription", new StringBody(fileDescription != null ? fileDescription : "")) ; multiPartEntity.addPart("fileName", new StringBody(fileName != null ? fileName : file.getName())) ; FileBody fileBody = new FileBody(file, "application/octect-stream") ; //Prepare payload multiPartEntity.addPart("attachment", fileBody) ; //Set to request body postRequest.setEntity(multiPartEntity) ; //Send request HttpResponse response = client.execute(postRequest) ; //Verify response if any if (response != null) { System.out.println(response.getStatusLine().getStatusCode()); } } catch (Exception ex) { ex.printStackTrace() ; } } } ``` **3）在应用中编写 RESTful API 以接受多部分请求** ```java package com.howtodoinjava.client.upload; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.List; import java.util.Map; import javax.ws.rs.Consumes; import javax.ws.rs.POST; import javax.ws.rs.Path; import javax.ws.rs.core.MultivaluedMap; import javax.ws.rs.core.Response; import org.apache.commons.io.IOUtils; import org.jboss.resteasy.plugins.providers.multipart.InputPart; import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput; @Path("/user-management") public class DemoFileSaver_MultipartFormDataInput { private final String UPLOADED_FILE_PATH = "c:\temp\"; @POST @Path("/image-upload") @Consumes("multipart/form-data") public Response uploadFile(MultipartFormDataInput input) throws IOException { //Get API input data Map<String, List<InputPart>> uploadForm = input.getFormDataMap(); //Get file name String fileName = uploadForm.get("fileName").get(0).getBodyAsString(); //Get file data to save List<InputPart> inputParts = uploadForm.get("attachment"); for (InputPart inputPart : inputParts) { try { //Use this header for extra processing if required @SuppressWarnings("unused") MultivaluedMap<String, String> header = inputPart.getHeaders(); // convert the uploaded file to inputstream InputStream inputStream = inputPart.getBody(InputStream.class, null); byte[] bytes = IOUtils.toByteArray(inputStream); // constructs upload file path fileName = UPLOADED_FILE_PATH + fileName; writeFile(bytes, fileName); System.out.println("Success !!!!!"); } catch (Exception e) { e.printStackTrace(); } } return Response.status(200) .entity("Uploaded file name : "+ fileName).build(); } //Utility method private void writeFile(byte[] content, String filename) throws IOException { File file = new File(filename); if (!file.exists()) { file.createNewFile(); } FileOutputStream fop = new FileOutputStream(file); fop.write(content); fop.flush(); fop.close(); } } ``` ```java [源码下载](https://docs.google.com/file/d/0B7yo2HclmjI4amhXRE5VMjBRSHM/edit?usp=sharing "multipart rest file upload") ``` **祝您学习愉快！**