无法从Jersey REST Web服务将JSON对象发送到Ajax

Question

I'm writing a simple Jersey REST web service where I'm consuming JSON object and sending another JSON object. This is just for the workaround. It throws the following error.

org.codehaus.jackson.map.JsonMappingException: No serializer found for class org.json.JSONObject and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) )

Ajax code

        $('#click').click(function() {
        $.ajax({
            url: "http://localhost:8080/test/rest/myService/jsonpost",
            method: "POST",
            data: jsonObj,
            dataType: 'application/json',
            contentType: "application/json",
             success: function(result){
                  alert(result);
             },
             error(){
                 alert("error");
                 console.log('Error');
             }
        });

    });

My code is :

@POST
@Path("/jsonpost")
@Consumes(MediaType.APPLICATION_JSON)
//@Produces(MediaType.APPLICATION_JSON)
@Produces({ MediaType.APPLICATION_JSON })
public Response consumeJSON( Track track ) {

    System.out.println("In post example");
    String output = track.toString();
    System.out.println("Post data"+output);
    JSONObject obj = new JSONObject();
    obj.put("1", "Shane");
    obj.put("2", "Bond");
    System.out.println(obj);

    return Response.status(200).entity(obj.toString()).build();
    //return Response.status(200).entity("success").build();
}

Whole error log

org.codehaus.jackson.map.JsonMappingException: No serializer found for class org.json.JSONObject and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) )
at org.codehaus.jackson.map.ser.StdSerializerProvider$1.failForEmpty(StdSerializerProvider.java:90)
at org.codehaus.jackson.map.ser.StdSerializerProvider$1.serialize(StdSerializerProvider.java:63)
at org.codehaus.jackson.map.ser.StdSerializerProvider._serializeValue(StdSerializerProvider.java:587)
at org.codehaus.jackson.map.ser.StdSerializerProvider.serializeValue(StdSerializerProvider.java:245)
at org.codehaus.jackson.map.ObjectMapper.writeValue(ObjectMapper.java:1145)
at org.codehaus.jackson.jaxrs.JacksonJsonProvider.writeTo(JacksonJsonProvider.java:520)
at com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy.writeTo(JacksonProviderProxy.java:160)
at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:306)
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:699)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

Answer 1

如果使用org.codehaus.jackson.map.ObjectMapper，则请在代码中使用以下几行。

mapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);

Answer 2

Jackson is meant to be used with POJOs (like your Track class). It doesn't know anything about or how to serialize those org.json objects. I would recommend to just use POJOs. The application will be a lot more maintainable with domain classes that clearly defining the domain.

With that being said, it is still possible to make it work with the org.json object or arbitrary key/value collections.

1. You can simple return a String instead of the JSONObject

    return Response.ok(obj.toString()); 

2. You can use a Map<String, String> instead. Jackson knows how to serialize those.

3. There is a support module for org.json , but it's only available for Jackson 2.x ( com.fasterxml not org.codehaus) .

   If you want to use Jackson 2.x, you can check out this post . Then you need to register the JsonOrgModule seen in the earlier link. You can do that in a ContextResolver , as seen in this post . Going this route, here is your checklist

   • Make sure you have the Jackson 2 dependency.
   • Make sure you register the Jackson packages with Jersey
   • Remove the older Jackson dependency
   • Implement the ContextResolver where you register the JsonOrgModule . This will allow Jackson to know about the org.json objects.

If you need help configuring the last option, please update your post with your web.xml and your dependencies