mybatis模糊查询

模糊查询在我们开发中是一项必不可缺少的重要内容。对于我们mybatis实现模糊查询有三种方式，以下具体的实现步聚：

1. 添加模糊查询的接口方法getStudentBySname

 List<Student> getStudentBySname1(String sname);
 List<Student> getStudentBySname2(String sname);
 List<Student> getStudentBySname3(String sname);

2.配置接口方法对应的sql文件

1) 配置占位符方式#{}

    <select id="getStudentBySname" parameterType="String" resultType="com.etime.pojo.Student">
        select * from student where sname like #{sname};
    </select>

2) 配置拼接字符串方式${}

    <select id="getStudentBySname2" parameterType="String" resultType="com.etime.pojo.Student">
        select * from student where sname like '%${value}%';
    </select>

我们在上面将原来的#{}占位符，改成了${value}。注意如果用模糊查询的这种写法，那么${value} 的写法就是固定的，不能写成其它名字。

3) 配置mysql函数方式concat

    <select id="getStudentBySname3" parameterType="String" resultType="com.etime.pojo.Student">
        select * from student where sname like concat('%',#{sname},'%');
    </select>

3. 模糊查询测试

    @Test
    public void t01() {
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        StudentDao studentDao = sqlSession.getMapper(StudentDao.class);
        String name = "安";
        String sname = "%" + name + "%";//最常用
        List<Student> list = studentDao.getStudentBySname1(sname);
        list.forEach(System.out::println);
        SqlSessionUtil.closeSqlSession(sqlSession);
    }
 
    @Test
    public void t02() {
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        StudentDao studentDao = sqlSession.getMapper(StudentDao.class);
        String sname = "安";
        List<Student> list = studentDao.getStudentBySname2(sname);
        list.forEach(System.out::println);
        SqlSessionUtil.closeSqlSession(sqlSession);
    }
 
    @Test
    public void t03() {
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        StudentDao studentDao = sqlSession.getMapper(StudentDao.class);
        String sname = "安";
        List<Student> list = studentDao.getStudentBySname3(sname);
        list.forEach(System.out::println);
        SqlSessionUtil.closeSqlSession(sqlSession);
    }

 查询结果：