spring4解决json返回null值为“null”字符串问题

pom.xml

 

<dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.0.4</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.0.4</version>
        </dependency>

 

 

代码：

 

public class CustomerObjectMapper extends ObjectMapper {
 
    {
        DefaultSerializerProvider.Impl sp = new DefaultSerializerProvider.Impl();
        sp.setNullValueSerializer(new NullSerializer());
        this.setSerializerProvider(sp);
    }
 
    public class NullSerializer extends JsonSerializer<Object> {
        public void serialize(Object value, JsonGenerator jgen, SerializerProvider provider) throws IOException,
                JsonProcessingException {
 
            jgen.writeString("");
        }
    }
 
}

 

 

 

 

spring配置：

<mvc:annotation-driven>
    <mvc:message-converters>
    <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    <property name="objectMapper">
    <bean class="com.ai.acodm.base.CustomerObjectMapper"></bean>
    </property>
    </bean>
    </mvc:message-converters>
 
    </mvc:annotation-driven>