怎么在IDEA里创建MyBatis?

怎么在IDEA里创建MyBatis？

最近在狂神说里看了mybatis，下面分享以下在idea里创建我的第一个mybatis程序

思路：搭建环境->导入Mybatis->编写代码->测试

1.搭建环境

搭建数据库

CREATE DATABASE mybatis;

use mybatis;

CREATE TABLE user(
	id INT(20) NOT NULL PRIMARY KEY,
	name VARCHAR(30) DEFAULT NULL,
	pwd VARCHAR(30) DEFAULT NULL
	)ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO user(id,name,pwd) VALUES
(1,'肖战','521'),
(2,'王一博','1314'),
(3,'成毅','99');

2.新建项目

1.新建一个普通的maven项目

2.删除src目录（以后在这个模块里建模块，不用在重新搭建环境）
3.导入maven依赖-------将下面的依赖代码置于 pom.xml 文件中

  <dependencies>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.2</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>
  </dependencies>

还有关于配置文件无法导出或生效问题会出现，我们在接着上一步在pom.xml里添加下面代码

<!--在build中配置resource，来防止我们资源导出失败问题-->
<build>
    <resources>
    	<resource>
    		<directory>src/main/resources</directory>
    		<includes>
    			<include>**/*.properties
    			**/*.xml</include>
    		</includes>
    		<filtering>true</filtering>
    	</resource>
    	<resource>
    		<directory>src/main/java</directory>
    		<includes>
    			<include>**/*.properties
    			**/*.xml</include>
    		</includes>
    		<filtering>true</filtering>
    	</resource>
    </resources>
</build>

3.创建一个模块

在此模块的里边新建一个普通maven项目
如图建包，备用

编写mybatis的核心配置文件
在resources包里建mybatis-config.xml文件,把以下代码复制进去

 <?xml version="1.0" encoding="UTF8" ?>
	<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="111"/>
            </dataSource>
        </environment>
    </environments>
   <!--  每一个Mapper.xml都需要在mybatis核心配置文件中注册-->
     <mappers>
         <mapper resource="dao/UserMapper.xml"/>
     </mappers>
</configuration>

编写mybatis工具类
在utils包里建MybatisUtils

   public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
        //既然有了sqlsessionfactory，顾名思义，我们就可以获得sqlsession的实列了
        //sqlsession完全包含了面向数据数执行sql命令所需的所有方法
        public static SqlSession getSqlSession(){
            return sqlSessionFactory.openSession();
    }
}

4.编写代码

实体类-------------在pojo包里建User

public class User {
    private int id;
    private String name;
    private String pwd;

    public User() {
    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    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 getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

 public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

Dao接口---------在dao包里建UserDao类

public interface UserDao {
    List<User> getUserList();
}

接口实现类由原来的UserDaoImpl转变为一个Mapper配置文件
在dao包里建UserMapper.xml

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- namespace=绑定一个对应的Dao/Mapper接口-->
<mapper namespace="dao.UserDao">
<!--select查询语句-->
    <select id="getUserList" resultType="pojo.User">
    <!--mybatis.user表示mybatis下的user表-->
    select * from user;
  </select>
</mapper>

5.测试

在test包里的java里建UserDaoTest类

public class UserDaoTest {
    @Test
    public void test(){
        //第一步：获得SqlSession对象
        SqlSession sqlSession= MybatisUtils.getSqlSession();

        try {
            //方式一：getMapper
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            List<User> userList = userDao.getUserList();

            //方式二
//        List userList=sqlSession.selectList("dao.UserDao.getUserList");

            for (User user : userList) {
                System.out.println(user);
            }
        }catch (Exception e) {
            e.printStackTrace();
        }finally{
            //关闭sqlsession
            sqlSession.close();
        }
    }
}