Question

我正在努力解决这个问题：

我们有一个带有Guava多重映射的Table类（简化代码，基本上是1个成员，2个构造函数，多重映射的getter和setter）：

public class Table {

    private LinkedHashMultimap<String,Field> fields;

    public Table(){
        this.fields = LinkedHashMultimap.create();
    };

    public Table (LinkedHashMultimap<String, Field> fields){
        this.fields= fields;
    }

    public LinkedHashMultimap<String, Field> getFields() {
        return fields;
    }

    public void setFields(LinkedHashMultimap<String, Field> fields) {
        this.fields = fields;
    }
}

我想使用jackson 2.4.3使用Spring MVC 3.2.11进行序列化。

POM相关的依赖关系是：

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-core</artifactId>
  <version>2.4.3</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>2.4.3</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>com.fasterxml.jackson.datatype</groupId>
  <artifactId>jackson-datatype-guava</artifactId>
  <version>2.4.3</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>3.2.11.RELEASE</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
  <version>3.2.11.RELEASE</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>servlet-api</artifactId>
  <version>2.5</version>
  <scope>provided</scope>
</dependency>

我的spring.xml 现在看起来像这样（跟随此example）

<bean id="abstractJacksonObjectMapper"
      class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"
      p:targetMethod="registerModule">
    <property name="targetObject">
        <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean"
              p:indentOutput="true">
            <!--<property name="featuresToDisable">-->
                <!--<util:constant static-field="com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES" />-->
            <!--</property>-->
        </bean>
    </property>
    <property name="arguments">
        <list>
            <bean class="com.fasterxml.jackson.datatype.guava.GuavaModule" />
        </list>
    </property>
</bean>

<bean id="abstractMappingJacksonHttpMessageConverter"
      class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"
      abstract="true"/>

<bean id="abstractMappingJacksonJsonView"
      class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"
      abstract="true"
      p:extractValueFromSingleKeyModel="true"/>

<bean id="jacksonObjectMapper" parent="abstractJacksonObjectMapper" />

<bean id="mappingJacksonHttpMessageConverter"
      parent="abstractMappingJacksonHttpMessageConverter"
      p:objectMapper-ref="jacksonObjectMapper"
      p:supportedMediaTypes="application/json" />

<bean id="mappingJacksonJsonView"
      parent="abstractMappingJacksonJsonView"
      p:objectMapper-ref="jacksonObjectMapper"
      p:contentType="application/json" />

我还使用扩展的Jackson2ObjectMapperFactoryBean尝试了另一种方法：

<!-- Json rendering configuration-->
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
    <property name="order" value="1" />
    <property name="mediaTypes">
        <map>
            <entry key="json" value="application/json" />
            <entry key="xml" value="application/xml" />
        </map>
    </property>
    <property name="defaultViews">
        <list>
            <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
                <property name="objectMapper">
                    <bean class="my.package.Jackson2ObjectMapperFactoryBean"/>
                </property>
            </bean>
        </list>
    </property>
    <property name="ignoreAcceptHeader" value="true" />
</bean>

然后FactoryBean看起来像这样：

package my.package;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.guava.GuavaModule;

public class Jackson2ObjectMapperFactoryBean extends org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean{

public ObjectMapper getObject(){

    ObjectMapper objectMapper =super.getObject();
    objectMapper.registerModule(new GuavaModule());

    return objectMapper;
}

}

我有一个工作正常的Test类，根本没有使用Spring（只测试Table.class + Jackson + guava）简化：

Table study = getTable();

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new GuavaModule());

String tableString = mapper.writeValueAsString(table);

它正确地序列化了：

{
  "fields":{
    "Field1":[
      {
        "index":0,
        "header":"Field1",
        "fieldType":"fieldtype",
        "description":null,
        "cleanHeader":null
      }
    ],
    "Field2":[
      {
        "index":1,
        "header":"Field2",
        "fieldType":"fieldtype",
        "description":null,
        "cleanHeader":null
      }
    ]
  }
}

使用spring（2种方法中的任何一种）我得到了：

{
  "fields":{
    "empty": false
  }
}

我的控制器有一个@ResponseBody注释，它返回一个表。

编辑：我正在深入调试春季课程（第一次，;-)）和org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor 正在处理请求。这与我的问题有关......我的spring xml是否与@ResponseBody注释有些矛盾？

任何想法我做错了什么？

注意：我需要Multimap，不能是标准的Java集合。

Answer 1

Dunno如果下面的解决方案完全适合您的问题，但是如果您想要将SpringBootApplication配置为序列化番石榴，您可以使用@Configuration这样增强@Bean类：

@Configuration
public class Application extends SpringBootServletInitializer {

    @Bean
    ObjectMapper customizeJacksonConfiguration() {
        ObjectMapper om = new ObjectMapper();
        om.registerModule(new GuavaModule());
        return om;
    }
}

Answer 2

我认为你需要在spring.xml中添加一个mvc：message-converters部分。例如

 <mvc:annotation-driven ignoreDefaultModelOnRedirect="true" >
    <mvc:message-converters>
        <bean class="org.springframework.http.converter.ResourceHttpMessageConverter"/>
        <bean class="org.springframework.http.converter.xml.Jaxb2RootElementHttpMessageConverter"/>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
    </mvc:message-converters>
</mvc:annotation-driven>

Answer 3

毕竟我发现@ResponseBody注释强制使用不同的“viewResolver”，即使用Jackson，但没有使用Guava模块。

所以，为了解决这个问题，我在Controller方法中删除了@ResponseBody注释：

<!-- language: java -->
@ResponseBody
@RequestMapping("table")
public Table getTable() {

不幸的是，这是返回：{Table：{...}}并且是由ValueHandlder（ModelAttributeMethodProcessor）引入的人工制品。

最后，现在正在做的是：

1.-恢复@ResponseBody 2.-在MappingJackson2HttpMessageConverter中注册Guava模块，默认情况下使用@ResponseBody处理程序。

这就是spring xml的样子：干净简洁：

<!-- JSON parser configuration-->
<bean id="guavaObjectMapper" class="com.fasterxml.jackson.databind.ObjectMapper"/>

<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject"><ref local="guavaObjectMapper" /></property>
    <property name="targetMethod"><value>registerModule</value></property>
    <property name="arguments">
        <list>
            <bean id="guavaModule" class="com.fasterxml.jackson.datatype.guava.GuavaModule"/>
        </list>
    </property>
</bean>


<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <ref  local="guavaObjectMapper"/>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

Spring MVC配置+ Jackson + Guava多图

3 个答案: