mybatis(入门)

首先创建表：建表Sql文件 

-- 导出 mybatis 的数据库结构
CREATE DATABASE IF NOT EXISTS `mybatis` /*!40100 DEFAULT CHARACTER SET utf8 */;
USE `mybatis`;
-- 导出  表 mybatis.t_user 结构
CREATE TABLE IF NOT EXISTS `t_user` (
  `username` varchar(50) DEFAULT NULL,
  `password` varchar(50) DEFAULT NULL,
  `nickname` varchar(50) DEFAULT NULL,
  `type` tinyint(4) DEFAULT NULL,
  `id` int(10) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

 1、创建mybatis-config.xml文件，在该文件中完成和数据库的连接设置操作

<?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>
    <properties resource="jdbc.properties" />
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 配置mybatis的pooled的数据源 -->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}" />
                <property name="url" value="${url}" />
                <property name="username" value="${username}" />
                <property name="password" value="${password}" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="edu/hhxy/btais/User.xml"/><!--加载mapper文件-->
    </mappers>
</configuration>

src/jdbc.properties

2、根据数据表创建相应的实体类

Address.java

package edu.hhxy.btais;

public class Address {
    private int id;
    private String name;
    private String phone;
    private String postcode;
    private User user;
    
    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 String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getPostcode() {
        return postcode;
    }
    public void setPostcode(String postcode) {
        this.postcode = postcode;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
}

 User.java 

package edu.hhxy.btais;

import java.util.List;

public class User {
    private int id;
    private String username;
    private String password;
    private String nickname;
    private int type;
    private List<Address> addresses;

    public List<Address> getAddresses() {
        return addresses;
    }

    public void setAddresses(List<Address> addresses) {
        this.addresses = addresses;
    }

    public int getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    public int getType() {
        return type;
    }

    public void setType(int type) {
        this.type = type;
    }
}

 3、创建mapper文件完成对实体类的映射，该文件同样是xml的文件

 User.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="edu.hhxy.btais.User"><!--名称空间-->
    <insert id="add" parameterType="edu.hhxy.btais.User"><!--全类名 包名+类名-->
        insert into t_user
        (username,password,nickname,type)
        value(#{username},#{password},#{nickname},#{type})
    </insert>
</mapper>

4、创建SQlSession，并且通过SqlSession完成对数据库的操作

package edu.hhxy.btais.test;

import java.io.IOException;
import java.io.InputStream;
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 edu.hhxy.btais.User;
public class TestFirstMybatis {

    public static void main(String[] args) {
        try {
            // 1、创建配置文件(mybatis-config.xml)的输入流
            InputStream is = Resources
                    .getResourceAsStream("mybatis-config.xml");
            System.out.println(is.available());
            // 2、创建SQLSessionFactory
            SqlSessionFactory factory = new SqlSessionFactoryBuilder()
                    .build(is);
            // 3、创建SQLSessioin
            SqlSession session = factory.openSession();
            // 4、调用mapper文件插入数据（调用之前需要将mapper文件加入到mybatis-config.xml中）
            User u = new User();
            u.setNickname("孙悟空");
            u.setPassword("123");
            u.setType(0);
            u.setUsername("wukong");
            session.insert("edu.hhxy.btais.User.add", u);
            session.commit();//别忘了提交
            session.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

5、最佳实践

1、创建相应的MyBatisUtil完成对Session的获取
2、不使用annotation完成sql的映射