Mybatis(一)

一、目录结构

 

二、代码

1、dao/UserDao

package cn.bijian.dao;

import cn.bijian.model.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserDao {
    /*
    查询所有User
     */
//    @Select("select * from user")
    List<User> findAll();

}

2、model/User

package cn.bijian.model;

import java.util.Date;

public class User {
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

3、dao/UserDao.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="cn.bijian.dao.UserDao">
    <select id="findAll" resultType="cn.bijian.model.User">
        select * from User;
    </select>
</mapper>

4、SqlMapConfig.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>
    <environments default="mysql">
        <environment id="mysql">
            <!--JDBC 事务管理器被用作当应用程序负责管理数据库连接的生命周期（提交、回退等等）的时候。当你将
            TransactionManager 属性设置成 JDBC，MyBatis 内部将使用 JdbcTransactionFactory 类创建
            TransactionManager。例如，部署到 Apache Tomcat 的应用程序，需要应用程序自己管理事务。-->
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">  <!--连接池-->
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
<!--        <mapper resource="cn/bijian/dao/UserDao.xml"></mapper>-->
       <mapper class="cn.bijian.dao.UserDao"></mapper>  <!--用注解方式，需移除dao.xml映射配置-->
    </mappers>
</configuration>

5、MybatisTest

package cn.bijian.test;


import cn.bijian.dao.UserDao;
import cn.bijian.model.User;
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.InputStream;
import java.util.List;


public class MybatisTest {
    public static void main(String[] args) throws IOException {
        // 1.获取配置文件
        InputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");
        // 2.创建SqlSessionFactory的构建者对象
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        // 3.根据构建者对象创建SqlSessionFactory
        SqlSessionFactory sqlSessionFactory = builder.build(inputStream);
        // 4.根据sqlSessionFactory生产SqlSession对象
        SqlSession session = sqlSessionFactory.openSession();
        // 5.根据SqlSession创建Dao接口的代理对象
        UserDao userDao = session.getMapper(UserDao.class);
        List<User> users = userDao.findAll();
        for (User user:users) {
            System.out.println(user);
        }
        session.close();
        inputStream.close();
    }
}