1.导入依赖

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.76</version>
</dependency>

2.SpringMVC配置

<mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
                <property name="features">
                    <list>
                        <value>WriteMapNullValue</value>
                        <value>QuoteFieldNames</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
</mvc:annotation-driven>

SSM配置fastjson