相关疑难解决方法(0)

@XmlRootElement
public class Todo {
    private String s = "test";

    public String getS() {
        return s;
    }

    public void setS(String s) {
        this.s = s;
    }

}

和服务:

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

    @GET
    @Produces({MediaType.APPLICATION_JSON })
    public List<Todo> getAllGadgets() {
        return Arrays.asList(new Todo[] { new Todo() });
    }

}

我的web.xml:

<servlet>
    <servlet-name>Jersey REST Service</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>com.sun.jersey.config.property.packages</param-name>
        <param-value>com.test</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>Jersey REST Service</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

如果我将MediaType.APPLICATION_XML设置为生成注释,则所有这些都有效.但对于JSON,我得到以下异常:

严重:映射异常响应:500(内部服务器错误)javax.ws.rs.WebApplicationException:com.sun.jersey.api.MessageException:Java类java.util.Arrays $ ArrayList和Java类型java的消息体编写器找不到.util.List和MIME媒体类型application/json

我使用Jersey 1.6,根据教程,JSON格式应该可以在没有任何额外编程的情况下使用JAXB.怎么了？

我正在尝试使用简单的Jersey + JSON示例,但我得到以下错误 message body writer for Java class com.test.jsonexample and MIME media type application/json was not found

我把以下jar文件用于获得适当的结果

asm-3.1.jar
jackson-core-asl-1.9.9.jar
jackson-jaxrs-1.9.9.jar
jackson-mapper-asl-1.9.9.jar
jackson-xc-1.9.9.jar
jersey-client-1.9.jar
jersey-core-1.9.1.jar
jersey-json-1.9.jar
jersey-server-1.9.1.jar
jettison-1.3.2.jar
jsr311-api-1.1.1.jar

为什么我会收到此类错误？错误日志在这里:

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 com.test.Jsonexample, and Java type class com.test.Jsonexample, 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:1437)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at …

@Path("/hello")
public class Hello {

    @POST
    @Path("{id}")
    @Produces(MediaType.APPLICATION_JSON)
    @Consumes(MediaType.APPLICATION_JSON)
    public JSONObject sayPlainTextHello(@PathParam("id")JSONObject inputJsonObj) {

        String input = (String) inputJsonObj.get("input");
        String output="The input you sent is :"+input;
        JSONObject outputJsonObj = new JSONObject();
        outputJsonObj.put("output", output);

        return outputJsonObj;
    }
} 

这是我的webservice(我正在使用Jersey API).但我无法找到一种方法从java rest客户端调用此方法来发送和接收json数据.我尝试了以下方式来编写客户端

ClientConfig config = new DefaultClientConfig();
Client client = Client.create(config);
WebResource service = client.resource(getBaseURI());
JSONObject inputJsonObj = new JSONObject();
inputJsonObj.put("input", "Value");
System.out.println(service.path("rest").path("hello").accept(MediaType.APPLICATION_JSON).entity(inputJsonObj).post(JSONObject.class,JSONObject.class));

但这显示以下错误

Exception in thread "main" com.sun.jersey.api.client.ClientHandlerException: com.sun.jersey.api.client.ClientHandlerException: A message body writer for Java type, class java.lang.Class, and MIME media …

我正在测试RESTful服务,当我执行时我得到异常,虽然我的类路径(WEB-INF/lib)中有以下jar,但我没有使用Maven,我的JDK版本是1.5.有关此问题的其他问题无助于解决问题.

代码段

@GET
@Produces("application/json")    
//@Produces({MediaType.APPLICATION_JSON}) tried this, didn't work either
public List<Emp> getEmployees() {        
    List<Emp> empList = myDAO.getAllEmployees();
    log.info("size   " + empList.size());
    return empList;
}

@XmlRootElement
public class Emp {
......

web.xml中

<servlet>
    <servlet-name>Jersey Web Application</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>com.sun.jersey.config.property.packages</param-name>
        <param-value>test.employees</param-value>
    </init-param>
    <init-param>
        <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
        <param-value>true</param-value>
    </init-param>
</servlet>

 <servlet-mapping>
    <servlet-name>Jersey Web Application</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

罐子列表

jersey-server-1.2.jar
jersey-core-1.2.jar
jsr311-api-1.1.jar
asm-3.1.jar
jaxb-api-2.0.jar
jaxb-impl-2.0.jar
jackson-xc-1.2.0.jar
jackson-jaxrs-1.2.0.jar
jackson-mapper-asl-1.2.0.jar
jackson-core-asl-1.2.0.jar
jettison-1.2.jar
jersey-client-1.2.jar
jersey-servlet-1.10.jar
jersey-json-1.8.jar

异常堆栈

 SEVERE: A message body writer for Java class java.util.ArrayList,
 and Java type …