mybatis传入list参数用法

在Service业务处理层次上面将参数进行包装
public Long selectCustomerCountMap(List customerIdList) {   
        Map maps = new HashMap();
        maps.put("customerIds", customerIdList);
        return customerMapper.selectCustomerCountMap(maps);
    }
    DAO层：
    Long selectCustomerCountMap(Map maps);
XML文件：

<select id="selectCustomerCountMap" parameterType="java.util.Map" resultType="java.lang.Long">
        select count(1) from np_customer_info where id in
        <foreach item="item" collection="customerIds" separator="," open="(" close=")" index="">  #{item, jdbcType=INTEGER}    
        </foreach> 
    </select>
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注意： 入参类型是java.util.Map而不再是List ,此时的collection属性值为Map中的Key值。