设置MyBaits中sql配置文件

<?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.wangYuan.mapper.EmpMapper">
    <!--
      测试入参类型
        基本数据类型|包装类 String Date JAVABEAN  数组 List Map
        JAVABEAN : 当sql需要的参数存在多个,并且为一个对象的不同属性,可以先把对个参数封装成javabean对象,然后作为一个入参传递
                   sql中占位符的名字需要匹配入参对象的属性名
        数组|list ：sql需要的多个参数是同种类型，一个字段的多个值，适合使用数组|list
              sql语句中需要使用foreach标签进行遍历
        Map : sql需要的多个参数,不属于一个对象的不不同属性值,可以封装为Map集合中的不同键值对
              sql中占位符的名字需要匹配键值对的key
    -->
    <!--int-->
    <select id="queryByDeptno" parameterType="int" resultType="Emp">
        select * from emp where deptno=#{deptno}
    </select>
    <!--String-->
    <select id="queryByName" parameterType="String" resultType="Emp">
        select * from emp where ename=#{ename}
    </select>
    <!--Date-->
    <select id="queryByDate" parameterType="Date" resultType="Emp">
        select * from emp where hiredate=#{date}
    </select>
<!--    JAVABEAN-->
    <select id="queryByEnameDeptno" parameterType="emp" resultType="Emp">
        select * from emp where ename=#{ename} or deptno=#{deptno}
    </select>
<!--    数组-->
    <select id="queryByIdAll" resultType="Emp">
        select * from emp where empno in (
        <!--遍历数组元素                  遍历出来的元素叫item   每个元素之间用，隔开-->
            <foreach collection="array" item="item" separator=",">
                #{item}
            </foreach>
        )
    </select>
<!--Map-->
    <select id="queryBySalDeptno" resultType="emp" parameterType="map">
        select * from emp where sal>#{sal} or deptno=#{deptno}
    </select>
</mapper>

java代码测试

public class test03 {
    //测试不同的入参类型
    public static void main(String[] args) throws ParseException {
        //获取sql连接
        SqlSession sqlSession = sessionUtils.getSqlSession();
        List<Emp> list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryByDeptno", 20);
        list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryByName", "wang");
        Date parse = new SimpleDateFormat("yyyy/MM/dd").parse("1981/12/3");
        list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryByDate", parse);
        Emp emp = new Emp();
        emp.setEname("ALLEN");
        emp.setDeptno(20);
        list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryByEnameDeptno", emp);
        list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryByIdAll", new int[]{6666,7369});
        list = sqlSession.selectList("com.wangYuan.mapper.EmpMapper.queryBySalDeptno", Map.of("sal","1500","deptno","30"));

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

使用的工具类sessionUtils

public class sessionUtils {
    private static SqlSessionFactory factory=null;
    static{
        try {
            //加载配置文件
            factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //获取数据库连接
    public static SqlSession getSqlSession(){
        SqlSession sqlSession=null;
        if(factory!=null){
            sqlSession = factory.openSession();//默认手动，提交事务
//            sqlSession= factory.openSession(true);//设置事务，自动提交
        }
        return sqlSession;
    }
}