Spring boot 和 mybatis 学习笔记3--动态sql

今天抽时间将mybatis 的动态sql 学习了一下，参照http://www.mybatis.org/mybatis-3/zh/dynamic-sql.html的文档，动态sql包括

if
choose (when, otherwise)
trim (where, set)
foreach

下面通过例子来一一介绍

一、动态sql 配置

<?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.thq.mybatis.dao.UserDynamicDao">
	<select id="selectList" resultType="com.thq.mybatis.model.User">
		select * from tb_user where true
		<if test="id != null">
			and id=#{id}
		</if>
		 <choose>
		 	 <when test="name != null">
		 		and name like #{name}
		 	 </when>
		 	 <otherwise>
      			      AND true
    		         </otherwise>
		 </choose>
	</select>
	<select id="selectListWhere" resultType="com.thq.mybatis.model.User">
		select * from tb_user
		<where>
			<if test="id!= null">
				and name=#{id}
			</if>
			<if test="name != null">
				and name like #{name}
			</if>
			
		</where>
		<!--  		
 	            prefix：前缀覆盖并增加其内容
                    suffix：后缀覆盖并增加其内容
                    prefixOverrides：前缀判断的条件 和where是等价的
                    suffixOverrides：后缀判断的条件
		<trim prefix="where" prefixOverrides="AND|OR" >
			<if test="id!= null">
				AND name=#{id}
			</if>
			<if test="name != null">
				AND name LIKE #{name}
			</if>
		</trim>
		-->
	</select>
	<update id="updateSet">
		UPDATE tb_user 
		<set>
			<if test="name != null ">name=#{name}</if>
		</set>
		WHERE id=#{id}
	</update>
	<!-- collection : array -->
	<select id="selectListByIdsArray" resultType="com.thq.mybatis.model.User">
		SELECT * FROM tb_user WHERE id in 
		<foreach item="item" index="index" collection="array" open="(" separator="," close=")">
			#{item}
		</foreach>
	</select>
	<!-- collection : list -->
	<select id="selectListByIdsList" resultType="com.thq.mybatis.model.User">
		SELECT * FROM tb_user WHERE id in 
		<foreach item="item" index="index" collection="list" open="(" separator="," close=")">
			#{item}
		</foreach>
	</select>
	<!-- collection: Dao 调用传入的参数为Map -->
	<select id="selectListByIdsMap" resultType="com.thq.mybatis.model.User">
		SELECT * FROM tb_user WHERE id in 
		<foreach item="item" index="index" collection="ids" open="(" separator="," close=")">
			#{item}
		</foreach>
	</select>
</mapper>

二、dao调用接口（mapper接口）

package com.thq.mybatis.dao;

import java.util.List;
import java.util.Map;

import com.thq.mybatis.model.User;

public interface UserDynamicDao {
	
	public List<User> selectList(User user);
	
	public List<User> selectListWhere(User user);
	
	public int updateSet(User user);
	
	public List<User> selectListByIdsArray(Integer[] ids);
	
	public List<User> selectListByIdsList(List<Integer>  ids);
	
	public List<User> selectListByIdsMap(Map<String,Object>  ids);
}

经测试，各接口都输出指定的数据

完毕

Spring boot 和 mybatis 学习笔记3--动态sql

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