mybatis的IDEA环境搭建步骤

第一种标准步骤，不需要创建实现类

此处不选用骨架直接next

设置你的mybatis项目的名字以及路径，点击finished

导入测试的数据库

选择自动导入坐标

写入所需要的jar包的坐标

<?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>org.example</groupId>
    <artifactId>mybatis_test_enviorment</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <dependencies>
        <dependency>
            <!--mybatis包-->
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <!--测试包-->
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
        <dependency>
            <!--日志包-->
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <!--数据库连接包-->
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
    </dependencies>


</project>

导入log4j.properties

在java包中创建domain 和 dao 包

在daomain包中创建一个User对象，其中的属性与数据库的中列的名字相同
（此处先讲 封装类的属性 与 数据库 列名相同的情况）

package com.xiao.domain;

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

/**
 * @_PackageName:com.xiao.domain
 * @_ClassName:User
 * @_Description:
 * @_Author：笑老二
 * @_data 2020/4/16 18:27
 */
public class User implements Serializable {
     
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

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

    public User() {
     
    }

    public User(Integer id, String username, Date birthday, String sex, String address) {
     
        this.id = id;
        this.username = username;
        this.birthday = birthday;
        this.sex = sex;
        this.address = address;
    }
}

创建UserDao接口，其中定义个findAll方法

package com.xiao.dao;

import com.xiao.domain.User;

import java.util.List;

public interface UserDao {
     

    /**
     * 查询所有用户
     * @return
     */

    List<User> findAll();
}

编写 持久层接口的件 映射文件 UserDao.xml
注意：

1. 这个UserDao.xml要写在resources下面
2. 项目的结构与java dao 的结构一致
   

写入内容

1. 其中 namesapce代表含有这个方法的位置
2. mapper中的id代表 要使用的方法名字
3. resultType代表返回的类型
   

配置mybatis的环境文件SqlMapConfig.xml
注意：

1. default 与 id 要一致
2. resource 代表了告知 mybatis 映射配置的位置

<?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mybatis的环境-->
    <environments default="mysql">
        <!--配置mysql的环境-->
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/eesy"/>
                <property name="username" value="root"/>
                <property name="password" value="1234"/>
            </dataSource>
        </environment>
    </environments>
    <!--告知mybatis映射配置文件位置-->
    <mappers>
        <mapper resource="com/xiao/dao/UserDao.xml"/>
    </mappers>
</configuration>

创建一个在test文件夹下写入mybatisTest.java进行测试
结构图

package com.xiao.test;

import com.xiao.dao.UserDao;
import com.xiao.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.InputStream;
import java.util.List;

/**
 * @_PackageName:com.xiao.test
 * @_ClassName:MybatisTest
 * @_Description:
 * @_Author：笑老二
 * @_data 2020/4/19 18:19
 */
public class MybatisTest {
     
    public static void main(String[] args) throws Exception{
     
        //1.加载配置文件进内存
        InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建一个工场生产的工具
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        //3.通过工程生产工具生产一个工厂对象
        SqlSessionFactory build = builder.build(is);
        //4.创建一个sqlSeesion对象
        SqlSession sqlSession = build.openSession();
        //5.强化类，创建代理对象，来创建实现类
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        List<User> users = userDao.findAll();
        for (User user : users) {
     
            System.out.println(user);
        }
        //6.关闭流
        sqlSession.close();
        is.close();
    }
}

运行成功图

第二种，需要创建实现类

省略以上重复的创建步骤
在dao包下创建一个impl包放入UserDaoImpl

写入的代码

package com.xiao.dao.impl;

import com.xiao.dao.UserDao;
import com.xiao.domain.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

/**
 * @_PackageName:com.xiao.dao.impl
 * @_ClassName:UserDaoImpl
 * @_Description:
 * @_Author：笑老二
 * @_data 2020/4/19 18:29
 */
public class UserDaoImpl implements UserDao {
     
    private SqlSessionFactory factory;
    private SqlSession sqlSession;

    //强制必须传入factory工厂对象

    public UserDaoImpl(SqlSessionFactory factory) {
     
        this.factory = factory;
    }

    public List<User> findAll() {
     
        sqlSession = factory.openSession();
        UserDao u = sqlSession.getMapper(UserDao.class);
        List<User> users = u.findAll();
        sqlSession.close();
        return users;
    }
}

mybatisTest代码

package com.xiao.test;

import com.xiao.dao.UserDao;
import com.xiao.dao.impl.UserDaoImpl;
import com.xiao.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.InputStream;
import java.util.List;

/**
 * @_PackageName:com.xiao.test
 * @_ClassName:MybatisTest
 * @_Description:
 * @_Author：笑老二
 * @_data 2020/4/19 18:19
 */
public class MybatisTest {
     
    public static void main(String[] args) throws Exception{
     
        //1.加载配置文件进内存
        InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建一个工场生产的工具
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        //3.通过工程生产工具生产一个工厂对象
        SqlSessionFactory factory = builder.build(is);
        UserDao userDao = new UserDaoImpl(factory);
        List<User> users = userDao.findAll();
        for (User user : users) {
     
            System.out.println(user);
        }
        //6.关闭流
        is.close();
    }
}

运行结果