那些遇到过的问题

通过REST Web服务获取数据会产生异常

Joe*_*jah 3 java rest netbeans web-services glassfish-3

我正在尝试创建一个使用REST将数据传递给客户端的Web服务.我现在卡在2个问题上,一个在客户端,一个在服务器端.我一直在尝试很多东西,然后我就更加困难了.我希望你们中的任何人都可以帮助我.

我尝试通过浏览器和整个应用程序来接近Web服务.如果我直接URL到服务器,我收到以下错误消息:

SEVERE: A message body writer for Java class java.util.ArrayList, and Java type java.util.Collection<domain.Tweet>, and MIME media type text/plain was not found
SEVERE: The registered message body writers compatible with the MIME media type are:
text/plain ->
  com.sun.jersey.core.impl.provider.entity.StringProvider
  com.sun.jersey.core.impl.provider.entity.ReaderProvider
*/* ->
  com.sun.jersey.core.impl.provider.entity.FormProvider
  com.sun.jersey.core.impl.provider.entity.MimeMultipartProvider
  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.json.impl.provider.entity.JSONJAXBElementProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONArrayProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONObjectProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONWithPaddingProvider
  com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONRootElementProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONListElementProvider$General
  com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy
  com.sun.jersey.moxy.MoxyMessageBodyWorker
  com.sun.jersey.moxy.MoxyListMessageBodyWorker
Run Code Online (Sandbox Code Playgroud)

如果我运行客户端应用程序,我收到以下错误消息:

Exception in thread "AWT-EventQueue-0" com.sun.jersey.api.client.UniformInterfaceException: GET http://localhost:8080/KwetterSOAP/resources/rest/user/Hans/tweets returned a response status of 500 Internal Server Error
    at com.sun.jersey.api.client.WebResource.handle(WebResource.java:688)
    at com.sun.jersey.api.client.WebResource.access$300(WebResource.java:74)
    at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:508)
    at service.RestClient.getTweets(RestClient.java:52)
    at kwettermonitor.KwetterFollowing.btnZoekFollowersActionPerformed(KwetterFollowing.java:103)
    at kwettermonitor.KwetterFollowing.access$000(KwetterFollowing.java:20)
    at kwettermonitor.KwetterFollowing$1.actionPerformed(KwetterFollowing.java:54)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2713)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
    at java.awt.EventQueue.access$000(EventQueue.java:101)
    at java.awt.EventQueue$3.run(EventQueue.java:666)
    at java.awt.EventQueue$3.run(EventQueue.java:664)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:680)
    at java.awt.EventQueue$4.run(EventQueue.java:678)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Run Code Online (Sandbox Code Playgroud)

Web服务已创建如下:

@Path("/rest")
@Stateless
public class RESTService {

    @Inject @Named(value = "kwetterService")
    private KwetterService service;

    @GET
    @Path("/user/{user}")
    @Produces(MediaType.TEXT_PLAIN)
    public User getUser(@PathParam("user") String userName)
    {
        return service.findByName(userName);
    }

    @GET
    @Path("/user/{user}/tweets")
    @Produces(MediaType.TEXT_PLAIN)
    public Collection<Tweet> getTweets(@PathParam("user") String userName)
    {
        System.out.println("Service: " + service);
        User user = service.findByName(userName);
        System.out.println(userName);
        System.out.println(user);
        return user.getTweets();
    }
Run Code Online (Sandbox Code Playgroud)

客户端如下: 

public class RestClient {
    private WebResource webResource;
    private Client client;
    private static final String BASE_URI = "http://localhost:8080/KwetterSOAP/resources";

    public RestClient() {
        DefaultClientConfig config = new DefaultClientConfig();
        client = Client.create(config);
        webResource = client.resource(BASE_URI).path("rest");
    }

    public User getUser(String userName) throws UniformInterfaceException {
        final WebResource.Builder userResource = webResource
           .path(String.format("/user/%s", userName))
           .accept(MediaType.TEXT_PLAIN) ;
        return userResource.get(User.class);
    }

    public Collection<Tweet> getTweets(String userName) throws UniformInterfaceException {
        final WebResource.Builder tweetResource = webResource
           .path(String.format("/user/%s/tweets", userName))
           .accept(MediaType.TEXT_PLAIN);
        return tweetResource.get(new GenericType<Collection<Tweet>>(){});
    }
Run Code Online (Sandbox Code Playgroud)

我也有点困惑的地方,就是放置@XML ...注释的地方.我已将该服务注释为根元素:

@Named(value = "kwetterService")
@Stateless
@XmlRootElement
public class KwetterService {
Run Code Online (Sandbox Code Playgroud)

我没有注释使用的方法:

public User findByName(String name)
    {
        return userDAO.getUser(name);
    }
Run Code Online (Sandbox Code Playgroud)

UserDAO接近数据库中的数据.我在这里没有为REST/XML添加任何内容.我也为User创建了一个XMLRootElement:

@Entity
@XmlRootElement
@Table(name="Users")
public class User implements Serializable {
Run Code Online (Sandbox Code Playgroud)

在方法getTweets()中,我添加了XMLElement注释:

@XmlElement
    public Collection<Tweet> getTweets() {
        List<Tweet> temp = new ArrayList<Tweet>(tweets);
        Collections.reverse(temp);
        return temp;
    }
Run Code Online (Sandbox Code Playgroud)

我自己的猜测是我对方法和类的完整注释是错误的.您可以看到任何错误？

Per*_*ion 6

请记住,JAX-RS的核心是构建在HTTP之上,而HTTP并不了解或关心Java对象.从资源方法返回对象时,必须将它们转换为可由请求客户端使用的数据.此转换由名为MessageBodyWriters的实体完成,并且所有JAX-RS实现都需要附带预先打包的一组.不幸的是,没有要求实现能够将您的对象转换为TEXT_PLAIN.从您发布的堆栈跟踪中,您实际上可以看到没有能够处理该媒体类型的提供程序:

com.sun.jersey.core.impl.provider.entity.FormProvider
com.sun.jersey.core.impl.provider.entity.MimeMultipartProvider
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
Run Code Online (Sandbox Code Playgroud)

但是,所有JAX-RS实现必须提供的翻译之一是从Java对象到XML的翻译.因此,您可以安全地将其用作数据格式.仅显示更改,您需要合并到现有代码中:

Java Bean:

@Entity
@XmlRootElement
@Table(name="Users")
public class User implements Serializable {

    @XmlWrapperElement("tweets")
    public Collection<Tweet> getTweets() {
        List<Tweet> temp = new ArrayList<Tweet>(tweets);
        Collections.reverse(temp);
        return temp;
    }
}
Run Code Online (Sandbox Code Playgroud)

服务器:

@Path("/rest")
@Stateless
public class RESTService {
    @GET
    @Path("/user/{user}")
    @Produces(MediaType.APPLICATION_XML)
    public User getUser(@PathParam("user") String userName);

    @GET
    @Path("/user/{user}/tweets")
    @Produces(MediaType.APPLICATION_XML)
    public Collection<Tweet> getTweets(@PathParam("user") String userName);
}
Run Code Online (Sandbox Code Playgroud)

客户:

public class RestClient {
    public User getUser(String userName) throws UniformInterfaceException {
        final WebResource.Builder userResource = webResource
           .path(String.format("/user/%s", userName))
           .accept(MediaType.APPLICATION_XML) ;
        return userResource.get(User.class);
    }

    public Collection<Tweet> getTweets(String userName)
        throws UniformInterfaceException {
        final WebResource.Builder tweetResource = webResource
           .path(String.format("/user/%s/tweets", userName))
           .accept(MediaType.APPLICATION_XML);
        return tweetResource.get(new GenericType<Collection<Tweet>>(){});
    }
}
Run Code Online (Sandbox Code Playgroud)

  • 如果你能在最后跳舞,这一切都是值得的!祝其他项目好运:) (2认同)

归档时间：

查看次数：

8275 次

最近记录：

13 年 前
相关归档
什么时候课程应该是可比较的和/或比较者？ 134
为什么StringBuilder#append(int)在Java 7中比在Java 8中更快？ 76
"new String()"也是不可变的吗？ 73
什么是Android中的sharedUserId,它是如何使用的？ 60
如何在Tomcat中为Web应用程序提供上下文配置？ 49
使用CXF使用HTTP基本身份验证使用Web服务时出现401错误 12
Mongolab REST API如何进行身份验证 12
对禁用资源的操作的预期 HTTP 状态代码 11
OpenAPI：OpenAPI 文档的标准位置和名称 7
如何使用rails创建Web服务？ 3
难疑归档
RESTful编程究竟是什么？ 3917
使用Git将我的最后一次X提交压缩在一起 3294
使用Git版本控制查看文件的更改历史记录 2920
如何制作一系列功能装饰器？ 2647
如何使div 100%的浏览器窗口高度？ 2016
为什么++ [[]] [+ []] + [+ []]返回字符串"10"？ 1613
你如何在YAML中阻止评论？ 1272
按列名从pandas DataFrame中删除列 1136
如何配置Visual Studio代码以始终在新选项卡中打开文件？ 1078
致命错误:Python.h:没有这样的文件或目录 1042