<!-- 多选 <choose> <when test="title != null"> AND title like #{title} </when> <when test="author != null and author.name != null"> AND author_name like #{author.name} </when> <otherwise> AND featured = 1 </otherwise> </choose> --> <!-- 循环 <foreach item="item" index="index" collection="list" open="(" separator="," close=")"> #{item} </foreach> --> <!-- trim 在这的作用是去掉所包含的前缀AND 或者OR 其他属性(suffixOverrides去掉后缀,加上前缀prefix,加上后缀suffix) <trim prefix="WHERE" prefixOverrides="AND |OR "> <if test="state != null"> state = #{state} </if> <if test="title != null"> AND title like #{title} </if> <if test="author != null and author.name != null"> AND author_name like #{author.name} </if> </trim> -->