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
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
|
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
|
1
2
3
4
5
6
7
8
9
10
|
<!-- 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> |