3

我正在按照本教程创建一个 CRUD RESTful WebService。

此类 WebService 的教程从第 7 段开始。我创建了服务器和客户端。

服务器似乎工作得非常好，因为我按照作者的建议对其进行了测试，并且一切都按预期工作。

但是，客户让我很难过。当我运行它时，我总是得到这个错误：

201
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><todoes><todo><id>3</id><summary>Blabla</summary></todo><todo><description>Read complete http://www.vogella.com</description><id>2</id><summary>Do something</summary></todo><todo><description>Read http://www.vogella.com/articles/REST/article.html</description><id>1</id><summary>Learn REST</summary></todo></todoes>
Exception in thread "main" com.sun.jersey.api.client.UniformInterfaceException: GET http://localhost:8080/CRUDserver/rest/todos returned a response status of 500 Internal Server Error
    at com.sun.jersey.api.client.WebResource.handle(WebResource.java:686)
    at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74)
    at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:507)
    at es.unican.cityInfo.client.Tester.main(Tester.java:34)

我无法理解的问题到底是什么？有任何想法吗 ？

我能做的唯一假设是基于作者在构建客户端开始时的这句话：

Create a new Java project called de.vogella.jersey.todo.client. Create a lib folder and place all jersey libs in this folder. Add the jars to the classpath of the project.

他说把所有东西都jersey libs放在一个文件夹里。但是这些库是什么？？？我为客户提供的唯一东西是 2 个 jar 文件：我在 jersey 网站上找到了这些jersey-client.jar文件......jersey-core.jar

正如这里所建议的，当我运行客户端时，来自服务器的日志：

Apr 26, 2013 5:46:19 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: A message body writer for Java class java.util.ArrayList, and Java type java.util.List<es.unican.cityInfo.model.Todo>, and MIME media type application/json was not found
Apr 26, 2013 5:46:19 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: The registered message body writers compatible with the MIME media type are:
*/* ->
  com.sun.jersey.core.impl.provider.entity.FormProvider
  com.sun.jersey.core.impl.provider.entity.StringProvider
  com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
  com.sun.jersey.core.impl.provider.entity.FileProvider
  com.sun.jersey.core.impl.provider.entity.InputStreamProvider
  com.sun.jersey.core.impl.provider.entity.DataSourceProvider
  com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$General
  com.sun.jersey.core.impl.provider.entity.ReaderProvider
  com.sun.jersey.core.impl.provider.entity.DocumentProvider
  com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider
  com.sun.jersey.core.impl.provider.entity.SourceProvider$SourceWriter
  com.sun.jersey.server.impl.template.ViewableMessageBodyWriter
  com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General

Apr 26, 2013 5:46:19 PM com.sun.jersey.spi.container.ContainerResponse logException
SEVERE: Mapped exception to response: 500 (Internal Server Error)
javax.ws.rs.WebApplicationException: com.sun.jersey.api.MessageException: A message body writer for Java class java.util.ArrayList, and Java type java.util.List<es.unican.cityInfo.model.Todo>, and MIME media type application/json was not found
    at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:285)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1479)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:662)
Caused by: com.sun.jersey.api.MessageException: A message body writer for Java class java.util.ArrayList, and Java type java.util.List<es.unican.cityInfo.model.Todo>, and MIME media type application/json was not found
    ... 24 more
4

3 回答 3

1

可能最简单的方法是使用 Jersey 的 POJO 支持功能。要启用它，请将 JSONConfiguration.FEATURE_POJO_MAPPING 初始化参数添加到 web.xml 的 servlet 配置中：

<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.api.json.POJOMappingFeature</param-name>
        <param-value>true</param-value>
    </init-param>
                  ...
    <load-on-startup>1</load-on-startup>
</servlet>

除了已有的罐子外，您可能还需要添加几个罐子。检查此链接以获取依赖项列表： https ://jersey.java.net/nonav/documentation/latest/chapter_deps.html#d4e1828

于 2013-04-27T02:01:15.633 回答
0

Since you are getting a 500 error, this means the code is erroring on the server side. You will have to look at the log on the server side to figure out what went wrong.

HTTP Status Codes are meant to give you information about the request.

See here

EDIT:

So it appears that your return type on the method being mapped to that HTTP request is JSON, but you have not registered a JSON message writer for Jersey to use.

于 2013-04-26T16:05:20.640 回答
0

原因：com.sun.jersey.api.MessageException：找不到 Java 类 java.util.ArrayList、Java 类型 java.util.List 和 MIME 媒体类型 application/json 的消息正文编写器

我认为您的 es.unican.cityInfo.model.Todo 类缺少以下注释 @XmlRootElement

IE

package de.vogella.jersey.jaxb.model;

import javax.xml.bind.annotation.XmlRootElement;

    @XmlRootElement // never forget me
    // JAX-RS supports an automatic mapping from JAXB annotated class to XML and JSON
    // Isn't that cool?
    public class Todo {
      private String summary;
      private String description;
      public String getSummary() {
        return summary;
      }
      public void setSummary(String summary) {
        this.summary = summary;
      }
      public String getDescription() {
        return description;
      }
      public void setDescription(String description) {
        this.description = description;
      }


    }
于 2014-05-28T14:14:08.127 回答