mybatis 動態代理方式操作資料庫

注意事項：

/*
 * 1、方法名和mapper.xml檔案中標籤的id相同
 * 2、該方法的輸入引數和mapper.xml檔案中標籤的parameterType相同
 * 3、該方法的返回值和mapper.xml檔案中標籤的resultType相同
 * 除了以上約定，要實現介面中方法和mapper.xml 中的SQL標籤一一對應，還需要以下兩點：
 * 1、namespace的值，就是介面的全類名（介面 <---> mapper.xml 一一對應）
 * 習慣：
 *  SQL對映檔案（mapper.xml）和介面放在同一個package下
 */
應用例子：

1、實體類

package com.mybatis02.bean;

/**
 * @author ：jack.zhao
 * @date ：2021-10-16 22:55
 */
public class Person {
    public Person() {
    }
    public Person(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }
    private int id;
    private String name;
    
 
private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    
 
public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

2、操作mybatis介面 mapper型別

package com.mybatis02.mapper;
import com.mybatis02.bean.Person;
import java.util.List;

/**
 * @author ：jack.zhao
 * @date ：2021-10-16 22:55
 */

// 操作mybatis介面 public interface PersonMapper { 
// 1、以下方法和mapper.xml 檔案id 一一對應
// 2、方法引數和mapper.xml檔案中標籤的parameterType相同 
// 3、方法的返回值和mapper.xml檔案中標籤的resultType相同 
Person queryPersonById(int id); 
List<Person> queryListPerson(); 
void addPerson(Person person);
void delStudentById(int id); 
void updateStudentById(Person person); }

3、mapper.xml 檔案

<?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.mybatis02.mapper.PersonMapper">
    <select id="queryPersonById" parameterType="int" resultType="com.mybatis02.bean.Person">
        select
            id,name,age
        from
            t_person
        where
            id = #{id}
    </select>
    
    <insert id="addPerson" parameterType="com.mybatis02.bean.Person">
        INSERT INTO t_person(id,name,age) VALUES (#{id},#{name},#{age})
    </insert>
    <delete id="delStudentById" parameterType="int">
        DELETE from t_person where id =#{id}
    </delete>
    
    <update id="updateStudentById"  parameterType="com.mybatis02.bean.Person">
        UPDATE t_person SET NAME =#{name},age = #{age} where id =#{id}
    </update>

    <select id="queryListPerson" resultType="com.mybatis02.bean.Person">
        select
        id,name,age
        from
        t_person
    </select>
</mapper>

4、測試類

package com.mybatis02.test;

import com.mybatis02.bean.Person;
import com.mybatis02.mapper.PersonMapper;
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.jupiter.api.Test;
import java.io.Reader;
import java.util.List;

/**
 * @author ：jack.zhao
 * @date ：2021-10-16 22:42
 */
public class test {

    /**
     * 根據ID查詢人的資訊
     */
    @Test
    public void test01() throws Exception{

        Reader reader = Resources.getResourceAsReader("mybatis-02.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession session = sessionFactory.openSession();
        // 動態代理
        PersonMapper personMapper = session.getMapper(PersonMapper.class);
        Person person = personMapper.queryPersonById(1001);
        System.out.println("根據ID查詢人員資訊為："+person);
        session.close();
    }

    // 查詢集合資訊
    @Test
    public void selectList() throws Exception{
        Reader reader = Resources.getResourceAsReader("mybatis-02.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession session = sessionFactory.openSession();
        // 動態代理
        PersonMapper personMapper = session.getMapper(PersonMapper.class);
        List<Person> personList = personMapper.queryListPerson();
        System.out.println("查詢所有人員資訊為："+personList);
        session.close();
    }

    // 增加人員資訊
    @Test
    public void addPerson() throws Exception{
        Reader reader = Resources.getResourceAsReader("mybatis-02.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession session = sessionFactory.openSession();
        Person persion = new Person(1003,"wangwu",29);
        // 動態代理
        PersonMapper personMapper = session.getMapper(PersonMapper.class);
        personMapper.addPerson(persion);
        session.commit(); // 因為配置的是JDBC方式需要手動執行commit操作
        System.out.println("新增人員資訊成功！");
        session.close();
    }

    // 根據ID刪除指定資訊
    @Test
    public void delPesonByID() throws Exception{
        Reader reader = Resources.getResourceAsReader("mybatis-02.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession session = sessionFactory.openSession();
        // 動態代理
        PersonMapper personMapper = session.getMapper(PersonMapper.class);
        personMapper.delStudentById(1003);
        session.commit(); // 因為配置的是JDBC方式需要手動執行commit操作
        System.out.println("刪除人員資訊成功！");
        session.close();
    }

    // 修改人員資訊
    @Test
    public void updateStudentById() throws Exception{
        Person person = new Person(1003,"maliu",26);
        Reader reader = Resources.getResourceAsReader("mybatis-02.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession session = sessionFactory.openSession();
        // 動態代理
        PersonMapper personMapper = session.getMapper(PersonMapper.class);
        personMapper.updateStudentById(person);
        session.commit(); // 因為配置的是JDBC方式需要手動執行commit操作
        System.out.println("修改人員資訊成功！");
        session.close();
    }
}