<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD SQL MAP Config 3.1//EN"
? ? "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
? <settings>
? ? <setting name="callSettersOnNulls" value="true"/>
? </settings>
</configuration>

spring-mybatis.xml

<!-- spring和MyBatis完美整合，添加mybatis的配置映射文件 -->
? <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
? ? <property name="dataSource" ref="dataSource"/>
? ? <property name="configLocation" value="classpath:mybatis-configuration.xml"/>
? ? <!-- 自動掃描mapping.xml文件 -->
? ? <property name="mapperLocations" value="classpath:mapping/*.xml"></property>
? </bean>

如果想要配置rate的默認值，例如“”字符串，則可以建立一個類，實現(xiàn)Mybatis的TypeHandler接口

public class EmptyStringIfNull implements TypeHandler<String> {
? ? @Override
? ? public String getResult(ResultSet rs, String columnName) throws SQLException {
? ? ?return (rs.getString(columnName) == null) ? "" : rs.getString(columnName);?
? ? }
? ? @Override
? ? public String getResult(ResultSet rs, int columnIndex) throws SQLException {
? ? ?return (rs.getString(columnIndex) == null) ? "" : rs.getString(columnIndex);
? ? }
? ? @Override
? ? public String getResult(CallableStatement cs, int columnIndex) ? throws SQLException {
? ? ?return (cs.getString(columnIndex) == null) ? "" : cs.getString(columnIndex);
? ? }
? ? @Override
? ? public void setParameter(PreparedStatement ps, int arg1, String str, JdbcType jdbcType) throws SQLException { }}

在sql.xml文件定義與使用如下如下

<resultMap id="find" type="java.util.LinkedHashMap">
? ? <result property="name" column="name" />
? ? <result property="phone" column="phone" />
? ? <result property="rate" column="rate" typeHandler="com.mybatis.EmptyStringIfNull"/>
</resultMap>

mybatis返回map空值未返回字段

mybatis 開啟CallSettersOnNulls

@Bean
public SqlSessionFactory sqlSessionFactoryBean() throws Exception
{
? ? SqlSessionFactoryBean sqlSessionFactoryBean = new ?? ? SqlSessionFactoryBean();
? ? sqlSessionFactoryBean.setDataSource(dataSource());
? ? Configuration configuration = new .Configuration();
? ? configuration.setCallSettersOnNulls(true);//map返回空字段消失問題
? ? PageInterceptor pagePlugin = new PageInterceptor();
? ? JalorResultSetInterceptor jalorResultSetPlugin = new JalorResultSetInterceptor();
? ? ProgramInterceptor programPlugin = new ProgramInterceptor();
? ? //添加插件
? ? sqlSessionFactoryBean.setPlugins(new Interceptor[] {pagePlugin, jalorResultSetPlugin, programPlugin});
? ? sqlSessionFactoryBean.setConfiguration(configuration);
? ? return sqlSessionFactoryBean.getObject();
}

以上為個人經驗，希望能給大家一個參考，也希望大家多多支持腳本之家。

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