mapper.xml传入参数为Map的正确做法

1. 错误用法

    <update id="updatePropertiesBatch" parameterType="java.util.Map">
        <foreach collection="codePropertiesMap.entrySet()" item="entry" separator=",">
            update payment_channel
            set properties = #{entry.value}
            where code = #{entry.key}
        </foreach>
    </update>

这样会报错:

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'key' in 'class java.lang.String'

	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:92)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:440)
	at com.sun.proxy.$Proxy74.update(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:287)
	at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.execute(MybatisMapperMethod.java:65)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:96)
	at com.sun.proxy.$Proxy75.updatePropertiesBatch(Unknown Source)

2. 正确用法

    <update id="updatePropertiesBatch" parameterType="java.util.Map">
        <foreach collection="codePropertiesMap" item="value" index="key"  separator=";">
            update payment_channel
            set properties = #{value}
            where code = #{key}
        </foreach>
    </update>

使用批量更新需要加入allowMultiQueries=true

3. 批量更新–没有设置allowMultiQueries=true时

<update id="updatePropertiesBatch" parameterType="java.util.Map">
        UPDATE payment_channel
        SET properties = CASE code
        <foreach collection="codePropertiesMap" index="key" item="value" separator=" " open="" close="">
            WHEN #{key} THEN #{value}
        </foreach>
        ELSE properties -- 如果没有匹配的code，则保持原值不变
        END,
        update_time = NOW() -- 更新时间戳
        WHERE code IN
        <foreach collection="codePropertiesMap" index="key" open="(" separator="," close=")">
            #{key}
        </foreach>
    </update>