1.加註解方式,第一個是返回json格式,第二個是文字格式

@RequestMapping(value="/getCartGoodsListByUserId",produces="application/json;charset=UTF-8")

@RequestMapping(value="/getCartGoodsListByUserId",produces = "text/plain;charset=utf-8") 

2.在mvc配置檔案中

 <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <property name="supportedMediaTypes">
                    <list>
                        <value>application/json;charset=UTF-8</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>