Question

我正在尝试使用JAX-RS学习RESTful Web服务的实现。

我有一个名为MovieObject的课程，其中包含有关电影的基本信息。一个名为ResourceHandler的类，负责处理请求并发送响应。

以下是我的 MovieObject.java

package org.auro.self.movielib.resource;

public class MovieObject {

    private String movieName;
    private String yearOfRelease;
    private int movieRating;

    public MovieObject(){

    }

    public MovieObject(String movieName, 
            String yearOfRelease, 
            int movieRating){

        this.movieName = movieName;
        this.yearOfRelease = yearOfRelease;
        this.movieRating = movieRating;
    }

    public String getMovieName(){
        return movieName;
    }


    public String getYearOfRelease(){
        return yearOfRelease;
    }

    public int getMovieRating(){
        return movieRating;
    }
}

以下是我的 ResourceHandler.java

package org.auro.self.movielib.resource;

import java.util.ArrayList;
import java.util.List;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("/message")
public class ResourceHandler {

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public List<MovieObject> getListOfMovies(){
        MovieObject mv1 = new MovieObject("The Independence Day 1", "1996", 7);
        MovieObject mv2 = new MovieObject("The Independence Day 2", "2016", 4);

        List<MovieObject> listOfMovies = new ArrayList<MovieObject>();

        listOfMovies.add(mv1);
        listOfMovies.add(mv2);

        return listOfMovies;
    }

}

以下是我的 index.jsp

<html>
<body>
    <h2>Jersey RESTful Web Application!</h2>
    <p><a href="webapi/myresource">Jersey resource</a>
    <p>Visit <a href="http://jersey.java.net">Project Jersey website</a>
    for more information on Jersey!

    <p> Get Movies <a href="webapi/message"> here</a>
</body>
</html>

最后， web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- This web.xml file is not required when using Servlet 3.0 container,
     see implementation details http://jersey.java.net/nonav/documentation/latest/jax-rs.html -->
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>Jersey Web Application</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>org.auro.self.movielib</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Jersey Web Application</servlet-name>
        <url-pattern>/webapi/*</url-pattern>
    </servlet-mapping>
</web-app>

如果您查看我的 index.jsp ，您会注意到<p> Get Movies <a href="webapi/message"> here</a>的任何请求实际上由 ResourceHandler.java

对该类的GET请求应该以纯文本形式返回电影列表，但我最终得到HTTP Status 500 - Internal Server Error

这就是我在控制台中获得的内容

INFO: Server startup in 2430 ms
Aug 20, 2016 11:52:58 PM org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor aroundWriteTo
SEVERE: MessageBodyWriter not found for media type=application/xml, type=class java.util.ArrayList, genericType=java.util.List<org.auro.self.movielib.resource.MovieObject>.

我是否遗漏了导致此错误的任何内容？

Answer 1

这是内容协商问题（misscommunication）。

您应该更改应用程序以返回xml而不是station_cfg={} station_cfg.ssid=SSID station_cfg.pwd=PASSWORD wifi.sta.config(station_cfg)：

TEXT_PLAIN

或使用包含@Produces({ MediaType.APPLICATION_XML })标头的请求调用您的服务（默认情况下为Accept: text/plain或类似内容）

您还可以尝试基于网址的内容协商，但这只是AFAIK Resteasy功能：

https://docs.jboss.org/resteasy/docs/3.0.6.Final/userguide/html/JAX-RS_Content_Negotiation.html

对RESTful资源的GET请求导致找不到MessageBodyWriter

1 个答案: