搭建Mybatis框架之创建Mybatis框的核心配置文件(个人笔记)

╰半夏微凉° 2024-04-01 02:13 4阅读 0赞

#### 搭建Mybatis框架 ####

*  1.在resources文件夹下面创建一个mybaits-config.xml文件
 *  2.创建StudentMapper接口,并写一个测试方法
 *  3.创建StudentMapper.xml映射文件,在第一步中的文件中添加映射
 *  4.编写测试函数

## 1.在resources文件夹下面创建一个mybaits-config.xml文件 ##

在其中配置driver,url,username,password

<?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/test?serverTimezone=GMT%2b8&useUnicode=true&characterEncoding=utf8&useSSL=false" />
                    <property name="username" value="root" />
                    <property name="password" value="123456" />
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            <mapper resource="mappers/StudentMapper.xml" />
        </mappers>
    </configuration>

## 2.创建StudentMapper接口,并写一个测试方法 ##

package mapper;
    
    public interface ProblemMapper {
        
        int insertProblem();
    }

## 3.创建StudentMapper.xml映射文件,在第一步中的文件中添加映射 ##

要注意的点如下  
1.mapper标签内部namespace的值需要和我们创建的接口的全类名保持一致,即mapper.ProblemMapper

2.insert内部的id的值需要和我们的类中的方法名保持一致  
sql语句在insert内部填写

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
      PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
      "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="mapper.ProblemMapper">
      
      
      <insert id="insertProblem">
        insert into problems values('芭芭拉','我跳的舞好看嘛','2022-11-06','芭芭拉,我要把你带回家',2)
      </insert>
    </mapper>

## 4.编写测试函数 ##

public static void main(String[] args) throws IOException {
        
            // 获取核心配置文件的输入流
            InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
            // 创建SqlSessionFactoryBuilder对象
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            // 创建SqlSessionFactory对象
            SqlSessionFactory SqlSessionFactory =  builder.build(inputStream);
            //获取sql的会话对象SqlSession,                   这里带一个true参数设置事务自动提交
            SqlSession session = SqlSessionFactory.openSession();
            //获取ProblemMapper接口的代理对象
            ProblemMapper mapper = session.getMapper(ProblemMapper.class);
            //调用mapper接口的方法
            //int result = mapper.insertProblem();
            //使用唯一标识找到sql并执行,唯一标识是全类名.id
            int result = session.insert("mapper.ProblemMapper.insertProblem");
            System.out.println("result = " + result);
            //提交事务
            session.commit();
            session.close();
        }