JSON乱码统一解决

通过Spring配置统一指定，这样就不用每次都去处理了！

我们可以在springmvc的配置文件上添加一段消息StringHttpMessageConverter 转换配置！

<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <constructor-arg value="UTF-8"/>
        bean>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="failOnEmptyBeans" value="false"/>
                bean>
            property>
        bean>
    mvc:message-converters>
mvc:annotation-driven>