带有 Jersey 2.23.2 的 RESTful JSON答案

【问题标题】：RESTful JSON with Jersey 2.23.2带有 Jersey 2.23.2 的 RESTful JSON
【发布时间】：2016-08-19 03:42:21
【问题描述】：

我是 Java、Jersey 和 RESTful 的新手。我最近下载了 Jersey jar 2.23.2 和 Jersey media moxy 2.23.2 以及 java-json 库。

我在 google 中看到了很多示例，但大多数示例都不同。没有一个确切的例子可以效仿。我尝试这样做，但仍然不知道如何使用 http 客户端使用帖子和获取方法。我在下面发布了代码。

另外，我使用邮递员测试了编码方法，但我在 post 方法上遇到错误。

SEVERE: Servlet.service() for servlet [Service] in context with path [/com.myexample] threw exception [org.glassfish.jersey.server.ContainerException: java.lang.NoClassDefFoundError: javax/json/JsonException] with root cause
java.lang.ClassNotFoundException: javax.json.JsonException

这些是库

这是我的 web.xml

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
      <display-name>com.myexample</display-name>
      <welcome-file-list>
        <welcome-file>default.html</welcome-file>
      </welcome-file-list>

      <servlet>
        <servlet-name>Service</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
          <param-name>jersey.config.server.provider.packages</param-name>
          <param-value>com.myexample.resources<param-value>
        </init-param>
        <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>
      <servlet-mapping>
        <servlet-name>Service</servlet-name>
        <url-pattern>/api/*</url-pattern>
      </servlet-mapping>  
    </web-app>

这是我创建的类：

public class Employee {

    private String firstName;
    private String lastName;

    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return this.firstName + " " + this.lastName;
    }

}

这是控制器/资源

package com.myexample.resources;

import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.json.JSONException;
import org.json.JSONObject;

@Path("/test")
public class MyResource {


    @GET
    @Path("getEmployee")
    @Produces(MediaType.APPLICATION_JSON)
    public Response getEmployee() throws JSONException{
        Employee employee = new Employee();
        employee.setFirstName("John");
        employee.setLastName("Smith");
        JSONObject json = new JSONObject();
        json.put("employee", employee);
        return Response.status(200).entity(employee).build();
    }


    @POST
    @Path("postEmployee")
    @Consumes(MediaType.APPLICATION_JSON)
    public Response postEmployee(Employee employee) throws JSONException{
        return Response.status(200).entity(employee.toString()).build();
    }
}

我尝试创建我的 http 客户端

    public class TestClient {

        public static void main(String[] args) {
            try {
                //POST
                Client client = ClientBuilder.newClient();
                WebTarget webTarget = client.target("http://localhost:8080/com.myexample/api/test/postEmployee");
                Employee emp = new Employee();
                emp.setFirstName("John");
                emp.setLastName("Smith");


                Invocation.Builder invocationBuilder =  webTarget.request(MediaType.APPLICATION_JSON);
                //<--As it crashes the following line of this comment, I still don't know how to get my entity
                Response response = invocationBuilder.post(Entity.entity(emp, MediaType.APPLICATION_JSON)); 
                //Employee emp = readEntity(Employee.class); //???
              } catch (Exception e) {
                e.printStackTrace();
              }

            //GET
            try {
                Client client = ClientBuilder.newClient();
                WebTarget webTarget = client.target("http://localhost:8080/com.myexample/api/test/getEmployee");
                Invocation.Builder invocationBuilder =  webTarget.request(MediaType.APPLICATION_JSON);
                Response response = invocationBuilder.get();
                //I get my response but how to deserialize the object
                //Employee emp = (Employee)response.getEntity(); //CRASH, cannot cast               
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

}

由于我仍然不知道如何在客户端上检索对象，但我使用邮递员来测试控制器。

这是使用 postman 的 get 方法的输出。有效

这是使用 postman 的 post 方法的输出。它不起作用

这是完全错误

Aug 18, 2016 11:37:59 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Service] in context with path [/com.myexample] threw exception [org.glassfish.jersey.server.ContainerException: java.lang.NoClassDefFoundError: javax/json/JsonException] with root cause
java.lang.ClassNotFoundException: javax.json.JsonException
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1313)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1164)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.getNewXMLReader(SAXUnmarshaller.java:200)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.getXMLReader(SAXUnmarshaller.java:188)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:425)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:375)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:708)
    at org.eclipse.persistence.internal.oxm.XMLUnmarshaller.unmarshal(XMLUnmarshaller.java:643)
    at org.eclipse.persistence.jaxb.JAXBUnmarshaller.unmarshal(JAXBUnmarshaller.java:339)
    at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.readFrom(MOXyJsonProvider.java:660)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.invokeReadFrom(ReaderInterceptorExecutor.java:256)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:235)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:155)
    at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundReadFrom(MappableExceptionWrapperInterceptor.java:74)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:155)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1085)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:874)
    at org.glassfish.jersey.server.ContainerRequest.readEntity(ContainerRequest.java:271)
    at org.glassfish.jersey.server.internal.inject.EntityParamValueFactoryProvider$EntityValueFactory.provide(EntityParamValueFactoryProvider.java:96)
    at org.glassfish.jersey.server.spi.internal.ParamValueFactoryWithSource.provide(ParamValueFactoryWithSource.java:71)
    at org.glassfish.jersey.server.spi.internal.ParameterValueHelper.getParameterValues(ParameterValueHelper.java:94)
    at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$AbstractMethodParamInvoker.getParamValues(JavaResourceMethodDispatcherProvider.java:127)
    at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:160)
    at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)
    at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:326)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
    at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:305)
    at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1154)
    at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:473)
    at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:427)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:388)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:341)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:228)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

【问题讨论】：

Maximus，您能否在此处包含参考实现 jar：jsonp.java.net/download.html，然后再试一次。
将java2s.com/Code/Jar/j/Downloadjavaxjson10jar.htm 添加到您的库中
感谢你们的 cmets 伙计们。非常感激。差不多了！！！我做了你所说的Ebrahim Pasbani，因为我不使用Maven。现在 Tomcat 没有崩溃，但我收到错误“HTTP 状态 400 - 错误请求。客户端发送的请求在语法上不正确。”
我看到了我的错误。我试图发送这个 {\"firstName\":\"John\",\"lastName\":\"Smith\"} 应该是这样的：{"firstName":"John","lastName": “史密斯”}通过邮递员。非常感谢你们。你的cmets救了我。您应该将其发布为答案。我仍然不知道如何使用 http 客户端获取我的对象，但我知道控制器正在工作。
如何运行服务器？

标签： java json rest

【解决方案1】：

您需要寻找 jersey-media-mody 的正确依赖项。使用https://jar-download.com/ 寻找依赖关系，尽管最好从现在开始使用 Maven，好吗？

版本号要非常具体。

【讨论】：

【解决方案2】：

来自Documentation，

搜索到的类定义在当前执行时存在类已编译，但无法再找到定义。

所以，当你构建你的战争时，缺少的依赖并没有被打包。

您开始的更好选择是使用 Maven。从原型创建一个 Maven 项目。

这里有一个关于如何构建rest api的非常简单的指南， REST API EXAMPLE

【讨论】：