Mybatis映射配置文件详解

mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="StudentMapper">
<select id="selectAll" resultType="demo1.bean.Student">
    SELECT * FROM student
select>
<select id="selectById" resultType="demo1.bean.Student" parameterType="java.lang.Integer">
    SELECT * FROM student WHERE sid = #{sid}
select>
mapper>

package demo1.bean;
 
public class Student {
    private Integer sid;
    private String name;
    private Integer age;
 
    public Student() {
    }
 
    public Student(Integer sid, String name, Integer age) {
        this.sid = sid;
        this.name = name;
        this.age = age;
    }
 
    @Override
    public String toString() {
        return "Student{" +
                "id=" + sid +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
 
    public Integer getId() {
        return sid;
    }
 
    public void setId(Integer sid) {
        this.sid = sid;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
}

package demo1.dao;
 
import demo1.bean.Student;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.*;
import org.junit.Test;
 
import java.io.InputStream;
import java.util.List;
 
public class StudentTest1 {
    @Test
    public void selectAll() throws Exception{
        //1.加载核心配置文件
        InputStream is = Resources.getResourceAsStream("MybatisConfig.xml");
        //2.获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
        //3.通过SqlSession工厂对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //4.执行映射配置文件中的sql语句，并接收结果
        List list = sqlSession.selectList("StudentMapper.selectAll");
        //5.处理结果
        for(Student stu : list){
            System.out.println(stu);
        }
        //6.释放资源
        sqlSession.close();
        is.close();
    }
    @Test
    public void selectById() throws Exception{
        //1.加载核心配置文件
        InputStream is = Resources.getResourceAsStream("MybatisConfig.xml");
        //2.获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
        //3.通过SqlSession工厂对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //4.执行映射配置文件中的sql语句，并接收结果
        List list = sqlSession.selectList("StudentMapper.selectById",3);
        //5.处理结果
        for(Student stu : list){
            System.out.println(stu);
        }
        //6.释放资源
        sqlSession.close();
        is.close();
    }
}