使用@responseBody遇见的异常

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下面是一个使用@responseBody的小例子：
必须有正确spring配置文件：

<mvc:annotation-driven>         <mvc:message-converters>             <bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">                 <property name="objectMapper">                     <bean class="com.fasterxml.jackson.databind.ObjectMapper">                         <property name="dateFormat">                             <bean class="java.text.SimpleDateFormat">                                 <constructor-arg type="java.lang.String" value="yyyy-MM-dd HH:mm:ss"/>                             </bean>                         </property>                     </bean>                 </property>             </bean>             <!-- 解决乱码问题 -->             <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" >                   <property name="messageConverters">                          <list>                              <bean class = "org.springframework.http.converter.StringHttpMessageConverter">                                 <property name = "supportedMediaTypes">                                    <list>                                        <value>text/html;charset=UTF-8</value>                                      </list>                                 </property>                              </bean>                          </list>                    </property>              </bean>         </mvc:message-converters>     </mvc:annotation-driven>

所需的maven的依赖库(必不可少)：

<dependencies>        <dependency>            <groupId>com.test1</groupId>            <artifactId>subtest1</artifactId>            <version>0.0.2-SNAPSHOT</version>        </dependency>        <dependency>            <groupId>org.apache.axis2</groupId>            <artifactId>axis2-adb</artifactId>            <version>${axis2.version}</version>        </dependency>        <dependency>            <groupId>org.apache.axis2</groupId>            <artifactId>axis2-transport-http</artifactId>            <version>${axis2.version}</version>        </dependency>        <dependency>            <groupId>org.apache.axis2</groupId>            <artifactId>axis2-transport-local</artifactId>            <version>${axis2.version}</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-core</artifactId>            <version>2.9.0.pr2</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-annotations</artifactId>            <version>2.9.0.pr2</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-databind</artifactId>            <version>2.9.0.pr2</version>        </dependency>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>javax.servlet-api</artifactId>            <scope>provided</scope>            <version>3.1.0</version>          </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-webmvc</artifactId>            <version>4.3.8.RELEASE</version>        </dependency>    </dependencies>

控制层代码：

import java.util.ArrayList;import java.util.Date;import java.util.List;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import com.pojo.TestBean;@Controllerpublic class ServiceC {    @RequestMapping(value="/jsontest")      public @ResponseBody List<TestBean> getJSON() {          List<TestBean> testBean = new ArrayList<TestBean>();          testBean.add(TestBean.generateContent("ee", new Date(), "test", "test"));          testBean.add(TestBean.generateContent("ee", new Date(), "test", "test"));          testBean.add(TestBean.generateContent("ee", new Date(), "test", "test"));          testBean.add(TestBean.generateContent("呃呃", new Date(), "呃呃", "test"));          return testBean;      }  }

在浏览器中访问：http://localhost:8080/（项目名）/jsontest，即可访问，页面中会返回一个上面testBean生成的json字符串

一. 浏览器返回406
@requestMapping中的注解参数可能有问题，它没有把返回值当成json处理。

二.浏览器返回500，javax.servlet.ServletException: Circular view path […]: would dispatch back to the current handler URL [/…] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)
对照以上正确的例子，@responseBody要加上，配置文件里的内容要写对。这里注意，配置文件中的类是新版本的json处理包com.fasterxml.jackson.core中的MappingJackson2HttpMessageConverter，而不是MappingJacksonHttpMessageConverter。

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