Spring Rest客户端实现：无法提取响应：没有为xstreamMarshaller找到适合的响应类型的HttpMessageConverter

Question

I am developing client server application using spring mvc and rest. Its simple calculator service in which client calls the methods from server to execute operations.

This is my rest client code restClient.java:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package com.blog.samples.client;

/**
 *
 * @author bhushan.baviskar
 */
import com.blog.samples.domain.Calculator;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.client.RestTemplate;

public class restClient {

  public static void main(String [] args)
  {
      restClient tmp = new restClient();
      tmp.calltoserver();
  }
  public void calltoserver() {
    ApplicationContext applicationContext = new ClassPathXmlApplicationContext("../../../../appContext.xml", restClient.class);
    RestTemplate restTemplate = applicationContext.getBean("restTemplate", RestTemplate.class);
    String url = "http://localhost:8080/rest/calc/4&3&+";
    Calculator calObj = (Calculator) restTemplate.getForObject(url, Calculator.class);
    System.out.println("details " + calObj.getDetails());
    System.out.println("done");
  }
}

And this is my appContext.xml file :

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd">

  <bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
        <property name="messageConverters">
      <bean id="messageConverter" class="org.springframework.http.converter.xml.MarshallingHttpMessageConverter">
        <property name="marshaller" ref="xstreamMarshaller" />
        <property name="unmarshaller" ref="xstreamMarshaller" />
      </bean>
    </property>
  </bean>

  <bean id="xstreamMarshaller" class="org.springframework.oxm.xstream.XStreamMarshaller">
    <property name="aliases">
    <props>
      <prop key="Calculator">com.blog.samples.webservices.rest.CalcController</prop>
    </props>
    </property>
  </bean>

</beans>

I am getting response in json format but when I execute the restclient.java file it says :

DEBUG: [Dec-11 16:54:39,706] web.client.RestTemplate - GET request for "http://localhost:8080/rest/calc/4&3&+" resulted in 200 (OK)

Exception in thread "main" org.springframework.web.client.RestClientException: **Could not extract response: no suitable HttpMessageConverter found for response type** [com.blog.samples.domain.Calculator] and content type [text/plain;charset=UTF-8]
    at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:84)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:446)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:401)
    at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:199)
    at com.blog.samples.client.restClient.calltoserver(restClient.java:27)
    at com.blog.samples.client.restClient.main(restClient.java:21)
------------------------------------------------------------------------

I am new to the Spring Rest client Development so any help will be appreciated.

If anyone knows pl. tell me How to handle the response?

Answer 1

This is because the MappingJacksonHttpMessageConverter is not registered to your restTemplate. By default all types of MessageConverters present in your classpath will be registered.

You should either remove property messageConverters for bean restTemplate in you xml to have default messageconverters or you have to add MappingJacksonHttpMessageConverter to your messageConverters list in your xml.

Hope this helps