Mybatis动态sql常用标签的使用

Mybatis动态sql常用标签的使用

mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.codejams.mapper.UserMapper">

<!--  抽取sql语句  -->
    <sql id="selectUser">select * from user</sql>

    <select id="findByConditions" resultType="user" parameterType="user">
        <include refid="selectUser"></include>

        <where>
            <if test="id!=0">
                and id = #{id}
            </if>
            <if test="username!=''">
                and username= #{username}
            </if>
            <if test="password!=''">
                and password= #{password}
            </if>
        </where>

    </select>

    <select id="findAll" resultType="user">
        <include refid="selectUser"></include>
    </select>

    <select id="findByIds" resultType="user" parameterType="list">
        <include refid="selectUser"></include>
        <where>
            <foreach collection="list" open="id in(" close=")" item="id" separator=",">
                #{id}
            </foreach>
        </where>
    </select>
</mapper>