编写第一个基于 mybaits测试实例

1、添加jar包
2、建库+表

create database mybatis;use mybatis;CREATE TABLE users(id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20), age INT);INSERT INTO users(NAME, age) VALUES('Tom', 12);INSERT INTO users(NAME, age) VALUES('Jack', 11);

3、添加ybatis的配置文件 mybatis.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><!--    development:开发模式    work: 工作模式 -->    <environments default="development">        <environment id="development">            <transactionManager type="JDBC" />            <dataSource type="POOLED">                <property name="driver" value="com.mysql.jdbc.Driver" />                <property name="url" value="jdbc:mysql://localhost:3308/mybatis" />                <property name="hzy" value="root" />                <property name="root" value="root" />            </dataSource>        </environment>    </environments></configuration>

4、定义表中的实体类

package com.test1;public class User {    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;    }    @Override    public String toString() {        return "User [id=" + id + ", name=" + name + ", age=" + age + ", getId()=" + getId() + ", getName()="                + getName() + ", getAge()=" + getAge() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode()                + ", toString()=" + super.toString() + "]";    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}

5、 定义操作 users 表的 sql 映射文件 userMapper.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE  mapper  PUBLIC  "-//mybatis.org//DTD Mapper3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.test1.userMapper"><!--     根据id得到一个user对象 --><select id="getUsers" parameterType="int" resultType="com.test1.User">    select * from users where id=#(id)</select></mapper>

6、 在 mybatis.xml 文件中注册 userMapper.xml

 <mappers>    <mapper resource="com/test1/userMapper.xml"/></mappers>

7、 编写测试代码：执行定义的 select 语句

public static void main(String[] args) throws IOException{        String resources="mybatis.xml";        //加载mybatis的配置文，也加载关联的映射文件        Reader reader=Resources.getResourceAsReader(resources);        //构建sqlSession的工厂        SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(reader);        //创建能执行的映射文件中的sql的sqlSession        SqlSession session=sessionFactory.openSession();        //映射sql的标识字符        String statement="com.test1.userMapper.getUsers";        //执行查询返回唯一user对象的sql        User user=session.selectOne(statement,1);        System.out.println(user);    }