mybatis动态标签——trim

<?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.xxx.dynamicSQL.mapper.EmpMapper">

    <!--
        trim标签：prefix、suffix在标签中内容前面或后面添加指定内容；
                 prefixOverrides，suffixOverrides在标签中内容前面或后面去掉指定内容；
    -->
    <select id="getEmp" resultType="emp">
        select * from t_emp
        <trim prefix="where" suffixOverrides="and">
            <if test="empName != null and empName != ''">
                emp_name = #{empName} and
            </if>
            <if test="age != null and age != ''">
                age = #{age} and
            </if>
            <if test="gender != null and gender != ''">
                gender = #{gender}
            </if>
        </trim>
    </select>
</mapper>

测试代码

 @Test
    public void test1(){
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        EmpMapper mapper = sqlSession.getMapper(EmpMapper.class);
        Emp emp = new Emp(null,"李四",11,"");
        List<Emp> list = mapper.getEmp(emp);

        list.forEach(System.out::println);
    }