RESTEasy - 文件下载示例 · HowToDoInJava 中文系列教程

# RESTEasy - 文件下载示例 > 原文： [https://howtodoinjava.com/resteasy/resteasy-file-download-example/](https://howtodoinjava.com/resteasy/resteasy-file-download-example/) [**RESTEasy**](http://resteasy.jboss.org/ "resteasy") 是 JBOSS 提供的 [**JAX-RS 规范**](https://jcp.org/en/jsr/detail?id=311 "jax-rs")的实现，用于构建 [**RESTful**](https://en.wikipedia.org/wiki/Representational_state_transfer "restful") Web 服务和 RESTful Java 应用。 RESTEasy 与 HTTP 媒体类型结合使用，以特定格式（例如图像，pdf 或文本）提供响应。为响应而支持多种媒体类型的配置的核心组件是[**`@Produces`**](https://docs.oracle.com/javaee/6/api/javax/ws/rs/Produces.html "Produces annotation")注解。可以在此[**链接**](https://en.wikipedia.org/wiki/Internet_media_type "media types")中找到此类媒体类型的完整列表。出于演示目的，我将展示下载一个图像，一个文本和一个 pdf 文件的示例。同样，您可以构建其他媒体类型（文件类型）。 ## 1）创建一个 Maven 项目 ```java mvn archetype:generate -DgroupId=com.howtodoinjava -DartifactId=RESTfulDemoApplication -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false mvn eclipse:eclipse -Dwtpversion=2.0 ``` ## 2）更新`pom.xml`文件中的 jax-rs 依赖项 ```java <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.howtodoinjava</groupId> <artifactId>RESTfulDemoApplication</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>RESTfulDemoApplication Maven Webapp</name> <url>http://maven.apache.org</url> <repositories> <repository> <id>jboss</id> <url>http://repository.jboss.org/maven2</url> </repository> </repositories> <dependencies>  <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> </dependencies> <build> <finalName>RESTfulDemoApplication</finalName> </build> </project> ``` ## 3）在`@Produces`注解中创建具有相应媒体类型的服务类和 API ```java package com.howtodoinjava.service; import java.io.File; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.PathParam; import javax.ws.rs.Produces; import javax.ws.rs.core.Response; import javax.ws.rs.core.Response.ResponseBuilder; import javax.ws.rs.core.Response.Status; @Path("/file-management") public class FileServer { @GET @Path("/{fileName}/text") @Produces("text/plain") public Response getFileInTextFormat(@PathParam("fileName") String fileName) { System.out.println("File requested is : " + fileName); //Put some validations here such as invalid file name or missing file name if(fileName == null || fileName.isEmpty()) { ResponseBuilder response = Response.status(Status.BAD_REQUEST); return response.build(); } //Prepare a file object with file to return File file = new File("c:/demoTxtFile.txt"); ResponseBuilder response = Response.ok((Object) file); response.header("Content-Disposition", "attachment; filename="howtodoinjava.txt""); return response.build(); } @GET @Path("/{fileName}/pdf") @Produces("application/pdf") public Response getFileInPDFFormat(@PathParam("fileName") String fileName) { System.out.println("File requested is : " + fileName); //Put some validations here such as invalid file name or missing file name if(fileName == null || fileName.isEmpty()) { ResponseBuilder response = Response.status(Status.BAD_REQUEST); return response.build(); } //Prepare a file object with file to return File file = new File("c:/demoPDFFile.pdf"); ResponseBuilder response = Response.ok((Object) file); response.header("Content-Disposition", "attachment; filename="howtodoinjava.pdf""); return response.build(); } @GET @Path("/{fileName}/image") @Produces("image/jpeg") public Response getFileInJPEGFormat(@PathParam("fileName") String fileName) { System.out.println("File requested is : " + fileName); //Put some validations here such as invalid file name or missing file name if(fileName == null || fileName.isEmpty()) { ResponseBuilder response = Response.status(Status.BAD_REQUEST); return response.build(); } //Prepare a file object with file to return File file = new File("c:/demoJpegFile.jpeg"); ResponseBuilder response = Response.ok((Object) file); response.header("Content-Disposition", "attachment; filename="howtodoinjava.jpeg""); return response.build(); } } ``` ## 4）将要下载的文件放在参考位置我正在引用“`c:/<文件>`”中的文件。在运行此示例之前，从下载链接中的分发文件夹复制文件，并将其粘贴到`c:`中。 ## 5）测试应用以下是在浏览器中显示的用于请求 URL 的下载窗口的快照： **`http://localhost:8080/RESTfulDemoApplication/file-management/demoTxtFile/text`** ![download_txt](https://img.kancloud.cn/27/12/2712815a51daba5ea55d72f42471371d_442x313.png) **`http://localhost:8080/RESTfulDemoApplication/file-management/demoPDFFile/pdf`** ![download_pdf](https://img.kancloud.cn/25/dd/25dd026b3ffb0eb826c4fe17daeb51f9_443x315.png) **`http://localhost:8080/RESTfulDemoApplication/file-management/demoJpegFile/image`** ![download_image](https://img.kancloud.cn/1b/91/1b9160cb2ce2a44b7e8d1bcb7b0a2049_433x312.png) 如果要下载以上示例的源代码，请遵循以下给定的链接。 **祝您学习愉快！**