mybatis-day1入门案例

首先应先创建maven工程

（jar包要导入,五个核心jar包）

如果测试运行时出现了不支持版本5，则要修改以下内容

类的路径如下

1.配置pom.xml依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day01_eesy_01mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </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>
</project>

1.创建User类

package com.itheima.domain;

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

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 + '\'' +
                '}';
    }
}

2.创建IUserDao接口

package com.itheima.interfaces;

import com.itheima.domain.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface IUserDao {
    /**
     * 查询所有操作
     */
//    @Select("select * from User")
    List<User> findAll();
}

3.配置SqlMapConfig.xml文件（注意开头的mybatis约束不要忘记）

<?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">
<!--mybatis的主配置文件-->
<configuration>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql的环境-->
        <environment id="mysql">
            <!--配置事务类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源（连接池)-->
            <dataSource type="POOLED">
                <!--配置数据库连接的4个基本信息-->
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/eesy?serverTimezone=UTC&characterEncoding=utf-8&useSSL=false"/>
                <property name="username" value="xxxxxxx"/>
                <property name="password" value="xxxxxxx"/>
            </dataSource>
        </environment>
    </environments>

    <!--使用注解配置-->
<!--    <mappers>-->
<!--        <mapper class="com.itheima.dao.IUserDao"/>-->
<!--    </mappers>-->

    <!--指定映射配置文件的位置，映射配置文件指的是每个dao独立的配置文件-->
    <mappers>
        <mapper resource="com/itheima/dao/IUserDao.xml"></mapper>
    </mappers>
</configuration>

4.配置映射文件IUserDao.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="com.itheima.interfaces.IUserDao">
    <!--配置查询所有-->
    <select id="findAll" resultType="com.itheima.domain.User">
        select *from user
    </select>
</mapper>

5.创建测试类

package com.itheima.test;
import com.itheima.domain.User;
import com.itheima.interfaces.IUserDao;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.log4j.lf5.util.Resource;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MybatisTest {

    public static void main(String[] args) throws IOException {
        //1.读取配置文件
        InputStream in= Resource.class.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接口代理对象
        IUserDao userDao = session.getMapper(IUserDao.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();
    }
}