mybatis返回map数据空值字段不显示
查询sql添加每个字段的判断空
IFNULL(rate,'') as rateResultType利用实体返回
不用map
springMVC+mybatis查询数据
返回resultType=”map”时，如果数据为空的字段，则该字段省略不显示，可以通过添加配置文件，规定查询数据为空是则返回null。
<?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"/>
<!-- 自动扫描mapping.xml文件 -->
<property name="mapperLocations" value="classpath:mapping/*.xml"></property>
</bean>如果想要配置rate的默认值，例如“”字符串，则可以建立一个类，实现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文件定义与使用如下如下
<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 开启CallSettersOnNulls
@Bean
public SqlSessionFactory sqlSessionFactoryBean() throws Exception
{
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSource());
Configuration configuration = new .Configuration();
configuration.setCallSettersOnNulls(true);//map返回空字段消失问题
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();
}以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
