MybatisBatchUpdate

方案一：采用mysql连接允许多条sql执行，将update语句分次执行，使用的是mybatis的foreach语法遍历执行，语句如下：

<!-- 批量更新用户信息 方式一 -->
<update id="updateUserItem"  parameterType="java.util.List">
	<foreach collection="list" item="item"  separator=";">
		update sys_user
		<set>
			<if test="item.username != null and item.username.trim() != ''">
				`username` = #{item.username},
			</if>
			<if test="item.password != null and item.password.trim() != ''">
				`password` = #{item.password},
			</if>
			<if test="item.realName != null and item.realName.trim() != ''">
				`real_name` = #{item.realName},
			</if>
			<if test="item.telephone != null and item.telephone.trim() != ''">
				`telephone` = #{item.telephone},
			</if>
			<if test="item.mail != null and item.mail.trim() != ''">
				`mail` = #{item.mail}
			</if>
		</set>
		where `id` = #{item.id}
	</foreach>
</update>

方案一：采取case when语法，使用的是mybatis的 trim语法 + foreach语法 执行，语句如下：

<!-- 批量更新用户信息 方式二 -->
	<update id="updateUserItem2"  parameterType="java.util.List">
		update sys_user
		<trim prefix="set" suffixOverrides=",">
			<trim prefix="username = case" suffix="end,">
				<foreach collection="list" item="item">
					<if test="item.username != null and item.username.trim() != ''">
						when id=#{item.id} then #{item.username}
					</if>
				</foreach>
			</trim>
			<trim prefix="password = case" suffix="end,">
				<foreach collection="list" item="item">
					<if test="item.password != null and item.password.trim() != ''">
						when id=#{item.id} then #{item.password}
					</if>
				</foreach>
			</trim>
			<trim prefix="real_name = case" suffix="end,">
				<foreach collection="list" item="item">
					<if test="item.realName != null and item.realName.trim() != ''">
						when id=#{item.id} then #{item.realName}
					</if>
				</foreach>
			</trim>
			<trim prefix="telephone = case" suffix="end,">
				<foreach collection="list" item="item">
					<if test="item.telephone != null and item.telephone.trim() != ''">
						when id=#{item.id} then #{item.telephone}
					</if>
				</foreach>
			</trim>
			<trim prefix="mail = case" suffix="end,">
				<foreach collection="list" item="item">
					<if test="item.mail != null and item.mail.trim() != ''">
						when id=#{item.id} then #{item.mail}
					</if>
				</foreach>
			</trim>
		</trim>
		<where>
			<foreach collection="list" item="item" open="( " separator=") or (" close=" )">
				id = #{item.id}
			</foreach>
		</where>
	</update>