package com.imooc.ibatis;

import com.imooc.mybatis.entity.Student;
import com.imooc.mybatis.utils.MyBatisUtils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.Reader;
import java.sql.Connection;
import java.util.List;

public class Testor {
    @Test
    public void testSqlSessionFactory() throws IOException {
        //利用Reader加载classpath下的mybatis-config.xml核心配置文件
        Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
        //初始化SqlSessionFactory对象,同时解析mybatis-config.xml文件
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        System.out.println("SessionFactory加载成功");
        SqlSession sqlSession = null;
        try {
            //创建SqlSession对象,SqlSession是JDBC的扩展类,用于与数据库交互
            sqlSession = sqlSessionFactory.openSession();
            //创建数据库连接(测试用)
            Connection connection = sqlSession.getConnection();
            System.out.println(connection);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (sqlSession != null) {
                //如果type="POOLED",代表使用连接池,close则是将连接回收到连接池中
                //如果type="UNPOOLED",代表直连,close则会调用Connection.close()方法关闭连接
                sqlSession.close();
            }
        }
    }
    @Test
    public void testSelectAll(){
        SqlSession session=null;
        try {
            session= MyBatisUtils.openSession();
           List<Student>list =session.selectList("student.selectAll");
            for(Student s :list){
                System.out.println(s.getName());
            }
        }catch (Exception e){
            throw e;
        }finally {
            MyBatisUtils.closeSession(session);
        }
    }
    public void testInsert(){
        SqlSession session=null;
        try{
            session=new MyBatisUtils().openSession();
            Student student= new Student();
            student.setRegNo(2020031901);
            student.setName("testStudent");
            student.setSex("male");
            student.setAge(25);
            student.setGrade("大二");
            student.setMajor("computer");
            int num=session.insert("student.insert",student);
            session.commit();
            System.out.println(student.getId());
        }catch(Exception e){
           if(session!=null){
               session.rollback();
           }throw e;
        }finally {
            MyBatisUtils.closeSession(session);
        }
    }

}

mybatis-comfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="mapUnderscoreTocamlCase" value="ture"/>
    </settings>
    <environments default="dev">
        <environment id="dev">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/student?useUnicode=true&amp;characterEncoding=UTF-8 "/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mappers/student.xml"></mapper>
    </mappers>
</configuration>

student.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="student">
<select id="selectAll" resultType="com.imooc.mybatis.entity.Student">
    select * from student
</select>

    <!--flushCache="true"在sql执行后强制清空缓存-->
    <insert id="insert" parameterType="com.imooc.mybatis.entity.Student" flushCache="true">
        INSERT INTO student(reg_no, name, sex, age, grade, major)
        VALUES (#{reg_no} , #{name} , #{sex}, #{age}, #{grade}, #{major})
        <selectKey resultType="Integer" keyProperty="id" order="AFTER">
        select last_insert_id()
        </selectKey>
    </insert>
</mapper>

MyBatisUtils.java

package com.imooc.mybatis.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.Reader;

/**
 * MyBatisUtils工具类,创建全局唯一的SqlSessionFactory对象
 */
public class MyBatisUtils {
    //利用static(静态)属于类不属于对象,且全局唯一
    private static SqlSessionFactory sqlSessionFactory = null;
    //利用静态块在初始化类时实例化sqlSessionFactory
    static {
        Reader reader = null;
        try {
            reader = Resources.getResourceAsReader("mybatis-config.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
            //初始化错误时,通过抛出异常ExceptionInInitializerError通知调用者
            throw new ExceptionInInitializerError(e);
        }
    }

    /**
     * openSession 创建一个新的SqlSession对象
     * @return SqlSession对象
     */
    public static SqlSession openSession(){
        //默认SqlSession对自动提交事务数据(commit)
        //设置false代表关闭自动提交,改为手动提交事务数据
        return sqlSessionFactory.openSession(false);
    }

    /**
     * 释放一个有效的SqlSession对象
     * @param session 准备释放SqlSession对象
     */
    public static void closeSession(SqlSession session){
        if(session != null){
            session.close();
        }
    }
}

entity.student.java

package com.imooc.mybatis.entity;

public class Student {
    private Integer id;
    private Integer regNo;
    private String name;
    private String sex;
    private Integer age;
    private String grade;
    private String major;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getRegNo() {
        return regNo;
    }

    public void setRegNo(Integer regNo) {
        this.regNo = regNo;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getGrade() {
        return grade;
    }

    public void setGrade(String grade) {
        this.grade = grade;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }
}