mybatis入门(一）创建java工程搭建mybatis环境

Posted 2022-02-22 lovis

先创建一个java工程MybatisProject,在src下面建包和实体类，并在数据库创建相同的person表，然后导入mybatis-3.4.6.jar包

package com.liusong.entity;

public class Person 
    private int id;
    private String name;
    private int age;

    public Person() 
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    

    public Person(int id, String stu_name, int age) 
        super();
        this.id = id;
        this.name = stu_name;
        this.age = age;
    

    public int getId() 
        return id;
    

    public void setId(int id) 
        this.id = id;
    

    public String getstu_name() 
        return name;
    

    public void setName(String stu_name) 
        this.name = stu_name;
    

    public int getAge() 
        return age;
    

    public void setAge(int age) 
        this.age = age;
    

    @Override
    public String toString() 
        return "编号：" + getId() + ", 姓名：" + getstu_name() + ", 年纪" + getAge();
    

 

在实体类下面创建一个XML文件PersonMapper.xml，将官方文档中的配置信息代码作为头信息导入,并将里面的配置改成自己的

<?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">
<!--映射文件路径 --> 
<mapper namespace="com.liusong.entity.PersonMapper"> 
 　　<select id="queryPersonById" resultType="com.liusong.entity.Person">  
 　　　　 select * from person where id = #id 
 　　</select> 
　</mapper>

 再创建配置信息config.xml，从官方文档导入头信息

 

 

并做修改，导入jdbc的驱动jar包

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">  
　　　　　　　　<!--配置数据库信息 -->　　
                <property name="driver" value="com.mysql.cj.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/shop?serverTimezone=UTC" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
<!--加载映射文件 -->
    <mappers>
        <mapper resource="com/liusong/entity/PersonMapper.xml" />
    </mappers>
</configuration>

写测试类测试一下

package com.liusong.entity;

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

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

public class TestDemo 
    public static void queryStudentById() throws IOException 
        //将config.xml变为流
        Reader reader = Resources.getResourceAsReader("conf.xml");
        //创建sessionFactory对象，sessionFactory是一个接口，不能new，需要用到SqlSessionFactoryBuilder，并使用其中的build(Reader reader)方法
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
        SqlSession session = sessionFactory.openSession();
        String stament = "com.liusong.entity.PersonMapper.queryPersonById";
        Person person = session.selectOne(stament, 1);
        System.out.println(person);
        session.close();
    


    public static void main(String[] args) throws IOException 
        queryStudentById();
    

测试结果：编号：1, 姓名：zs, 年纪23