一、环境配置

1.依赖配置

<!-- pom.xml -->
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>8</source>
                <target>8</target>
            </configuration>
        </plugin>
    </plugins>
</build>
<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.26</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.7</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13</version>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.6</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.7.32</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.2.7</version>
    </dependency>
    <dependency>
        <groupId>org.freemarker</groupId>
        <artifactId>freemarker</artifactId>
        <version>2.3.31</version>
    </dependency>
</dependencies>

2.数据库配置

<!-- resources/mappers/mybatis-config.xml -->
<environments default="dev">
    <environment id="dev">
        <transactionManager type="JDBC"></transactionManager>
        <!--变更过的数据连接池，POOLED更改整合Druid-->
        <dataSource type="com.imooc.dataSource.DruidDataSourceFactory">
            <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
            <property name="url"
                      value="jdbc:mysql://localhost:3306/imooc-oa?useUnicode=true&amp;characterEncoding=UTF8&amp;serverTimeZone=Asia/Shanghai"/>
            <property name="username" value="root"/>
            <property name="password" value="123456"/>
        </dataSource>
    </environment>
</environments>

3.创建数据库连接工具类

package com.imooc.utils;

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.Reader;
import java.util.function.Function;

public class mybatisUtils {
    private static SqlSessionFactory sqlSessionFactory = null;
    static{
        try {
            Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static Object executeQuery(Function<SqlSession,Object> func){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        try {
            Object obj = func.apply(sqlSession);
            return obj;
        } finally {
            sqlSession.close();
        }
    }
}

4.创建Druid工具类

package com.imooc.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
import org.apache.ibatis.datasource.unpooled.UnpooledDataSourceFactory;

import javax.sql.DataSource;
import java.sql.SQLException;

public class DruidDataSourceFactory extends UnpooledDataSourceFactory {
    public DruidDataSourceFactory() {
        this.dataSource = new DruidDataSource();
    }

    public DataSource getDataSource() {
        try {
            ((DruidDataSource) this.dataSource).init();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        return this.dataSource;
    }
}

5. Maven项目增加Web模块

在项目配置里面Modules增加Web模块，修改path（将路径放到项目的src/main中），更名为webapp 。
在Facets中，修改开发描述和Web资源目录中的Path，具体和上一步目录地址相同。

6.配置Tomcat调试器

修改端口为浏览器默认端口80，方便调试。
Deployment增加Web项目， 应用上下文更改为 / ，方便调试。

7. 常用配置头

<!-- mybatis.xml -->
<?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">

<!-- mappers.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">

二、具体实战

待续...