mybatis入门

mybatis的入门程序

• 1. 在idea中新建maven工程
• 2. 添加依赖坐标，打开pom.xml文件，添加mybatis,mysql,junit,log4j的坐标依赖

<dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
        </dependency>
      <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
</dependencies>

• 3. 新建数据库mybaties,建一个user表

CREATE TABLE `mybaties`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '用户名称',
  `birthday` datetime NULL DEFAULT NULL COMMENT '生日',
  `sex` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '性别',
  `address` varchar(256) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '地址',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 49 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;

4. 在src下mian目录下新建一个一个User类，放在com.liquan.domain

package com.liquan.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @auth nan
 * @create 2019-12-23 21:12
 */
public class User implements Serializable {
    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 + '\'' +
                '}';
    }
}

• 5 新建UserDao接口，放在com.liquan.dao包

package com.liquan.dao;

import com.liquan.domain.User;

import java.util.List;

/**
 * @auth nan
 * @create 2019-12-22 18:45
 */
public interface UserDao {
    /***
     * 查询所有的接口
     * @return
     */
    List<User> findAll();
}

6. 在resource下新建SqlMapConfig.xml,内容如下：

<?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>
    <!--配置mysql的环境-->
    <environments default="mysql">
        <environment id="mysql">
            <!--配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源（这里配置连接池）-->
            <dataSource type="POOLED">
                <!--配置连接数据库的四个基本属性-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybaties"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <!--指定映射配置文件的位置-->

    <mappers>
        <mapper resource="com/liquan/dao/UserDao.xml"></mapper>
    </mappers>
</configuration>

• 7 在resouce下新建UserDao.xml位于com.liquan.dao目录下

<?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.liquan.dao.UserDao">
  <select id="findAll" resultType="com.liquan.domain.User">
   select * from user
  </select>
</mapper>

• 8 在test目录下新建一个测试类MybaitsTest,如下：

package com.liquan.test;

import com.liquan.dao.UserDao;
import com.liquan.domain.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;

/**
 * @auth nan
 * @create 2019-12-23 21:26
 */
public class MybatisTest {
    public static void main(String[] args) throws Exception {
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.使用工厂生产SqlSession对象
        SqlSession session = factory.openSession();
        //4.使用SqlSession创建Dao接口的代理对象
        UserDao userDao = session.getMapper(UserDao.class);
        //5.使用代理对象执行方法
        List<User> users = userDao.findAll();
        for(User user : users){
            System.out.println(user);
        }
        //6.释放资源
        session.close();
        in.close();
    }
}

运行测试类就可以得到user