Mybatis操作

1.创建一个maven项目，在pom文件中添加mybatis和mysql-connector-java模块
2.创建domain包，包内实体类Student，定义name，sex，age属性，重写构造方法

package org.example.domain;
public class Student {
    private String name;
    private String sex;
    private int age;
    public Student(String name, String sex, int age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }
}

3.在resource目录下创建mybatis.xml配置文件

<?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>
<!--    设置实体类的别名-->
    <typeAliases>
<!--        对于每个实体类单独配置别名（不区分大小写）-->
<!--        <typeAlias alias="student" type="org.example.domain.Student"/>-->
        <!--对于整个包进行配置，所有的实体类别名为类名（不区分大小写-->
        <package name="org.example.domain"/>
    </typeAliases>
<!--    设置环境配置，default为不指定时的默认配置-->
    <environments default="development">
        <environment id="development">
<!--            事务管理JDBC-->
            <transactionManager type="JDBC"/>
<!--            连接池配置-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
<!--    指定mybatis加载mapper映射文件的地址-->
    <mappers>
<!--        对于整个包进行配置，加载包内所有的mapper文件-->
        <package name="org.example.dao"/>
<!--        对于单个xml文件的相对路径进行配置-->
<!--        <mapper resource="org/example/dao/StudentDao.xml"/>-->
    </mappers>
</configuration>

4.创建dao包，StudentDao.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">
<!--命名空间绑定StudentDao.java-->
<mapper namespace="org.example.dao.StudentDao">
<!--    select操作语句-->
    <select id="selectStudents" resultType="Student">
        select * from student order by id
    </select>
<!--    insert操作语句，#{}占位-->
    <insert id="insertStudent">
        insert into student values (#{name},#{sex},#{age})
    </insert>
</mapper>

5.dao包下创建StudentDao.java接口

package org.example.dao;
import org.example.domain.Student;
import java.util.List;
public interface StudentDao {
    // 定义方法，方法名与mapper映射文件中的id一一对应
    Student queryStudentByName(); // 通过姓名搜索学生
    List<Student> queryStudents(); // 获取全部学生信息
    int insertStudent(); // 插入学生
}

6.配置静态资源文件

<resources>
   <resource>
     <directory>src/main/java</directory>
     <filtering>false</filtering>
     <includes>
       <include>**/*.xml</include>
     </includes>
   </resource>
   <resource>
     <directory>src/main/resources</directory>
     <filtering>true</filtering>
   </resource>
</resources>

7.调用

package org.example;
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.example.dao.StudentDao;
import org.example.domain.Student;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class App 
{
    public static void main( String[] args )
    {
        // 设置配置文件名
        String config = "mybatis.xml";
        try {
            // 读取配置文件为输入流
            InputStream in = Resources.getResourceAsStream(config);
            // 创建factory
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
            // 获取sqlSession
            SqlSession sqlSession = factory.openSession();
            // 创建实体类Student
            Student student = new Student("liu","nan",17);
            // 第一种操作方法
			// String insertSqlId = "org.example.dao.StudentDao.insertStudent";
			// int res = sqlSession.insert(insertSqlId,student);
			// System.out.println(res);
            // 第二种操作方式
            StudentDao studentDao = sqlSession.getMapper(StudentDao.class);
            int res = studentDao.insertStudent(student);
            System.out.println(res);
            // 调用queryStudents方法
            List<Student> results = studentDao.queryStudents();
            results.forEach(stu -> System.out.println(stu));
            // 使用commit提交数据
            sqlSession.commit();
            // 关闭sqlSession
            sqlSession.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果目录为