前提:
ssm框架已经搭建成功,能够正常进行增删改查操作。
下面来看UserMapper.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.six.dao.UserDao"> <resultMap id="userMapper" type="com.six.pojo.User"> <id column="id" property="userId"/> <result column="user_name" property="userName"/> <result column="user_age" property="userAge"/> <result column="user_sex" property="userSex"/> </resultMap> <insert id="addOneUser" parameterType="com.six.pojo.User"> INSERT INTO t_user <trim prefix="(" suffix=")" suffixOverrides=","> <if test="userName != null and userName != ''"> user_name, </if> <if test="userAge != null and userAge != ''"> user_age, </if> <if test="userSex != null and userSex != ''"> user_sex, </if> </trim> <trim prefix="values (" suffix=")" suffixOverrides=","> <if test="userName != null and userName != ''"> #{userName}, </if> <if test="userAge != null and userAge != ''"> #{userAge}, </if> <if test="userSex != null and userSex != ''"> #{userSex}, </if> </trim> </insert> </mapper>
prefix:在trim标签内sql语句上加上前缀
suffix:在trim标签内sql语句上加上后缀
suffixOverrides:指定去除多余的后缀内容,如 suffixOverrides="," 表示去掉 trim 标签内sql语句的多余后缀 ","
prefixOverrides:指定去掉多余的前缀内容