@Produces Annotation

The information sent to a resource and then passed back to the client is specified as a MIME media type in the headers of an HTTP request or response. You can specify which MIME media types of representations a resource can respond to or produce by using the following annotations:

•  javax.ws.rs.Consumes
•   javax.ws.rs.Produces

By default, a resource class can respond to and produce all MIME media types of representations specified in the HTTP request and response headers.

@Produces Annotation
The @Produces annotation is used to specify the MIME media types or representations a resource can produce and send back to the client. If @Produces is applied at the class level, all the methods in a resource can produce the specified MIME types by default. If applied at the method level, the annotation overrides any @Produces annotations applied at the class level.
If no methods in a resource are able to produce the MIME type in a client request, the JAX-RS runtime sends back an HTTP “406 Not Acceptable” error.

Example: 

@Produces("image/png"): for downloading png image file.

Steps:

1.       WEB.xml :

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">   <display-name>com.tushar.jersey.Project</display-name>   <welcome-file-list>     <welcome-file>index.html</welcome-file>     <welcome-file>index.htm</welcome-file>     <welcome-file>index.jsp</welcome-file>     <welcome-file>default.html</welcome-file>     <welcome-file>default.htm</welcome-file>     <welcome-file>default.jsp</welcome-file>   </welcome-file-list>     <servlet>                                 <servlet-name>jersey-serlvet</servlet-name>                                 <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer </servlet-class>                                 <init-param>                                      <param-name>com.sun.jersey.config.property.packages</param-name>                                      <param-value>com.tushar.jersey.Project</param-value>                                 </init-param>                                 <load-on-startup>1</load-on-startup>                 </servlet>       <servlet-mapping>                                 <servlet-name>jersey-serlvet</servlet-name>                                 <url-pattern>/rest/*</url-pattern>                 </servlet-mapping> </web-app>

2. FileDownload.java

package com.tushar.jersey.Project; import java.io.File;  import javax.ws.rs.GET;  import javax.ws.rs.Path;  import javax.ws.rs.Produces;  import javax.ws.rs.core.Response;  import javax.ws.rs.core.Response.ResponseBuilder; @Path("/files") public class FileDownload {                       private static final String FILE_PATH_IMAGE = "d:\\image.jpg";                                            @GET                      @Path("/image")                      @Produces("image/png")                      public Response getImageFile() {                          File file = new File(FILE_PATH_IMAGE);                          ResponseBuilder response = Response.ok((Object) file);                          response.header("Content-Disposition","attachment; filename=\"javatpoint_image.png\"");                          return response.build();                                         }                                         }

URL : http://localhost:8080/com.tushar.jersey.Project/rest/file/image

Clicking Open will open the file and save will save the file in the defined destination.

When Clicked the file will show the image file: