java - 从 restful java 客户端获取 JSON 输出

Question

我正在使用 REST (Jersey 1.8) 开发网络服务。目前，我正在使用 XML 在 Java 客户端和服务器之间进行通信。

我需要将其更改为 JSON:我该怎么做？我有一堆从 NetBeans 自动生成的代码，但不知道该做什么以及如何做。当测试服务时，它会显示 JSON 数据。我无法做的是在我的 main 方法中处理它。

这些是我遵循的教程

• http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/RESTfulWebServices/RESTfulWebservices.htm
• http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/RESTfulWebServices_Part2/RESTfulWebservicesPart2.htm
• http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/RESTfulWebServices_Part3/RESTfulWebservicesPart3.htm

我的 Java 客户端 main 方法:

public class SOATestClient {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        PersonJerseyClient client = new PersonJerseyClient();
        ClientResponse response = client.findAll_XML(ClientResponse.class);


        GenericType<List<Person>> genericType = new GenericType<List<Person>>() {
        };
// Returns an ArrayList of Players from the web service
        List<Person> data = new ArrayList<Person>();
        data = (response.getEntity(genericType));
        System.out.println("Retreiving and Displaying Players Details");
        for (Person person : data) {
            System.out.println("FirstName: " + person.getName());
            System.out.println("ID : " + person.getId());
            System.out.println(" Age : " + person.getAge());
        }
        client.close();
    }
}

个人 Jersey

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package jerseyclients;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.UniformInterfaceException;
import com.sun.jersey.api.client.WebResource;

/**
 * Jersey REST client generated for REST resource:PersonFacadeREST
 * [entity.person]<br>
 *  USAGE:
 * <pre>
 *        PersonJerseyClient client = new PersonJerseyClient();
 *        Object response = client.XXX(...);
 *        // do whatever with response
 *        client.close();
 * </pre>
 *
 * @author rj45
 */
public class PersonJerseyClient {
    private WebResource webResource;
    private Client client;
    private static final String BASE_URI = "http://localhost:8080/SOATestService/resources";

    public PersonJerseyClient() {
        com.sun.jersey.api.client.config.ClientConfig config = new com.sun.jersey.api.client.config.DefaultClientConfig();
        client = Client.create(config);
        webResource = client.resource(BASE_URI).path("entity.person");
    }

    public void remove(String id) throws UniformInterfaceException {
        webResource.path(java.text.MessageFormat.format("{0}", new Object[]{id})).delete();
    }

    public String countREST() throws UniformInterfaceException {
        WebResource resource = webResource;
        resource = resource.path("count");
        return resource.accept(javax.ws.rs.core.MediaType.TEXT_PLAIN).get(String.class);
    }

    public <T> T findAll_XML(Class<T> responseType) throws UniformInterfaceException {
        WebResource resource = webResource;
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType);
    }

    public <T> T findAll_JSON(Class<T> responseType) throws UniformInterfaceException {
        WebResource resource = webResource;
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType);
    }

    public void edit_XML(Object requestEntity) throws UniformInterfaceException {
        webResource.type(javax.ws.rs.core.MediaType.APPLICATION_XML).put(requestEntity);
    }

    public void edit_JSON(Object requestEntity) throws UniformInterfaceException {
        webResource.type(javax.ws.rs.core.MediaType.APPLICATION_JSON).put(requestEntity);
    }

    public void create_XML(Object requestEntity) throws UniformInterfaceException {
        webResource.type(javax.ws.rs.core.MediaType.APPLICATION_XML).post(requestEntity);
    }

    public void create_JSON(Object requestEntity) throws UniformInterfaceException {
        webResource.type(javax.ws.rs.core.MediaType.APPLICATION_JSON).post(requestEntity);
    }

    public <T> T findRange_XML(Class<T> responseType, String from, String to) throws UniformInterfaceException {
        WebResource resource = webResource;
        resource = resource.path(java.text.MessageFormat.format("{0}/{1}", new Object[]{from, to}));
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType);
    }

    public <T> T findRange_JSON(Class<T> responseType, String from, String to) throws UniformInterfaceException {
        WebResource resource = webResource;
        resource = resource.path(java.text.MessageFormat.format("{0}/{1}", new Object[]{from, to}));
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType);
    }

    public <T> T find_XML(Class<T> responseType, String id) throws UniformInterfaceException {
        WebResource resource = webResource;
        resource = resource.path(java.text.MessageFormat.format("{0}", new Object[]{id}));
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_XML).get(responseType);
    }

    public <T> T find_JSON(Class<T> responseType, String id) throws UniformInterfaceException {
        WebResource resource = webResource;
        resource = resource.path(java.text.MessageFormat.format("{0}", new Object[]{id}));
        return resource.accept(javax.ws.rs.core.MediaType.APPLICATION_JSON).get(responseType);
    }

    public void close() {
        client.destroy();
    }

}

我尝试通过以下方式访问它，并以与 XML 相同的方式处理它，

ClientResponse response = client.findAll_JSON(ClientResponse.class);

但它给了我

Exception in thread "main" javax.ws.rs.WebApplicationException: javax.xml.bind.UnmarshalException
 - with linked exception:
[com.sun.istack.internal.SAXParseException2; lineNumber: 0; columnNumber: 0; unexpected element (uri:"", local:"id"). Expected elements are <{}person>]
    at com.sun.jersey.core.provider.jaxb.AbstractListElementProvider.readFrom(AbstractListElementProvider.java:251)
    at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:553)
    at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:523)
    at soatestclient.SOATestClient.main(SOATestClient.java:33)
Caused by: javax.xml.bind.UnmarshalException

如果你能在这件事上帮助我，我将不胜感激。谢谢!

Answer 1

我解决了同样的问题。如果您的异常是:意外元素(uri:"", local:"id")…………

不要忘记添加以下代码:

    DefaultClientConfig clientConfig = new DefaultClientConfig();
    clientConfig.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, Boolean.TRUE);
    Client client = Client.create(clientConfig);

然后是代码:

return resource.type(MediaType.APPLICATION_JSON_TYPE).get(new GenericType<List<MyClass>>(){});

会好的。