在SpringMVC中，可以通过在<mvc:annotation-driven>中配置<mvc:message-converters>，把null值统一转换为空字符串，解决这个问题。下面以JSon交互的方式为例说明如何实现：
第一步：创建一个ObjectMapper
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package com.xjj.anes.mvc.converter; import java.io.IOException; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializerProvider; /** * @description: 转换null对象为空字符串 */ public class JsonObjectMapper extends ObjectMapper { private static final long serialVersionUID = 1L; public JsonObjectMapper() { super(); // 空值处理为空串 this.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() { @Override public void serialize(Object value, JsonGenerator jg, SerializerProvider sp) throws IOException, JsonProcessingException { jg.writeString(""); } }); } } |
第二步：在SpringMVC配置文件中，把新建的ObjectMapper注入给MappingJackson2HttpMessageConverter
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<!-- 注册RequestMappingHandlerMapping 和RequestMappingHandlerAdapter 两个bean。--> <mvc:annotation-driven> <mvc:message-converters> <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"> <property name="objectMapper"> <bean class="com.xjj.anes.mvc.converter.JsonObjectMapper"></bean> </property> </bean> </mvc:message-converters> </mvc:annotation-driven> |