Java之路 SpringMvc全局处理数据库null数据

SpringMVC配置文件：

<!-- Jackson -->
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<!-- 避免IE执行AJAX时,返回JSON出现下载文件 -->
<!-- <property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
</list>
</property> -->
<!-- 前台显示null 数据  为 空串 -->
<property name="objectMapper">
<bean class="com.huiyou.ljk.util.JsonMapper"></bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>

package com.huiyou.ljk.util;

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;
/**
*
* @author zhaobin
* <br/>
* SpringMVC 统一处理 null 数据 显示为 空字符串
*
*/
public class JsonMapper extends ObjectMapper{

/**
*
*/
private static final long serialVersionUID = 1L;

public JsonMapper() {
super();
// 允许单引号
/*this.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
// 字段和值都加引号
this.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
// 数字也加引号
this.configure(JsonGenerator.Feature.WRITE_NUMBERS_AS_STRINGS, true);
this.configure(JsonGenerator.Feature.QUOTE_NON_NUMERIC_NUMBERS, true); */

// 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("");
}
});
}
}//这样配置完  数据库查到的null数据前台就会显示为空字符串