开发环境

1. IDE: Eclipse

2. 数据库: Mysql 5.7

3. 数据库连接工具：DBeaver

步骤

1. 新建maven工程，命名为learnMybaits

2. 在pom.xml中引入mybatis、 mysql驱动和Junit的依赖

   pom.xml

   <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.auuid</groupId>
       <artifactId>mybatis</artifactId>
       <version>0.0.1-SNAPSHOT</version>
   
       <dependencies>
           <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
           <dependency>
               <groupId>org.mybatis</groupId>
               <artifactId>mybatis</artifactId>
               <version>3.4.6</version>
           </dependency>
           <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
               <version>8.0.11</version>
           </dependency>
           <!-- https://mvnrepository.com/artifact/junit/junit -->
           <dependency>
               <groupId>junit</groupId>
               <artifactId>junit</artifactId>
               <version>4.11</version>
               <scope>test</scope>
           </dependency>
       </dependencies>
   </project>
   

3. 新建一个Employee类，新建一张employee表

   Employee类

   package com.auuid.bean;
   
   public class Employee {
   
     private Integer id;
     private String name;
     private Integer age;
     
     public Integer getId() {
       return id;
     }
     public void setId(Integer id) {
       this.id = id;
     }
     public String getName() {
       return name;
     }
     public void setName(String name) {
       this.name = name;
     }
     public Integer getAge() {
       return age;
     }
     public void setAge(Integer age) {
       this.age = age;
     }
   }
   
   

   employee表

   CREATE TABLE employee (
     id INT PRIMARY KEY AUTO_INCREMENT,
     name VARCHAR(255),
     age SMALLINT
   )
   

4. 新建EmployeeMapper接口

   package com.auuid.dao;
   
   import com.auuid.bean.Employee;
   
   public interface EmployeeMapper {
     public Employee getById(Integer id);
     public void save(Employee employee);
     public void update(Employee employee);
     public void deleteById(Integer id);
   }
   

5. 新建配置文件EmployeeMapper.xml和mybatis-config.xml

   EmployeeMapper.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">
   <!-- namespace必须是EmployeeMapper类的全类名 -->
   <!-- select 标签的id属性必须是EmployeeMapper类的方法名 -->
   <mapper namespace="com.auuid.dao.EmployeeMapper">
      <!-- resultType 是返回值的全类名 -->
      <select id="getById" resultType="com.auuid.bean.Employee">
          select * from employee where id = #{id}
      </select>
      <!-- useGeneratedKeys： 使用数据库生成的key
           keyProperty： 指定这个key赋给Employee对象的那个字段
       -->
      <insert id="save" useGeneratedKeys="true" keyProperty="id">
          insert into employee(name, age) values(#{name}, #{age})
      </insert>
      <update id="update">
          update employee set name=#{name}, age=#{age} where id=#{id}
      </update>
      <delete id="deleteById">
          delete from employee where id=#{id}
      </delete>
   </mapper>
   

   mybatis-config.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">
   <configuration>
      <environments default="development">
          <environment id="development">
              <transactionManager type="JDBC" />
              <dataSource type="POOLED">
                  <property name="driver" value="com.mysql.cj.jdbc.Driver" />
                  <property name="url" value="jdbc:mysql://localhost:3306/mybatis?serverTimezone=GMT%2B8&amp;useSSL=false" />
                  <property name="username" value="root" />
                  <property name="password" value="123456" />
              </dataSource>
          </environment>
      </environments>
      <mappers>
          <mapper resource="EmployeeMapper.xml" />
      </mappers>
   </configuration>
   

6. 新建测试类EmployeeTestCase

   package com.auuid;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.util.Random;
   import java.util.UUID;
   
   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 org.junit.Test;
   
   import com.auuid.bean.Employee;
   import com.auuid.dao.EmployeeMapper;
   
   public class EmployeeTestCase {
     
     @Test
     public void save() throws IOException {
       SqlSession openSession = null;
       
       try {
         openSession = openSession();
         EmployeeMapper employeeMapper = openSession.getMapper(EmployeeMapper.class); //生产接口代理对象
         employeeMapper.save(newEmployee());
         openSession.commit();
       } finally {
         openSession.close();
       }
     }
     
     private SqlSession openSession() throws IOException {
       InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml"); //读取数据源
       SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //构建sessionFactory
       SqlSession openSession = sqlSessionFactory.openSession(); //构建session
       return openSession;
     }
     
     private Employee newEmployee() {
       Employee employee = new Employee();
       employee.setName(UUID.randomUUID().toString());
       employee.setAge(new Random().nextInt(100));
       return employee;
     }
   }