import java.sql.*;

public class DatabaseTest {

    public static void main(String[] args) throws SQLException, ClassNotFoundException {

        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8", "root", "123456");
        Statement statement = conn.createStatement();
        String sql = "select * from user where id = ?";
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.setInt(1, 2);
        ResultSet resultSet = preparedStatement.executeQuery();
//        ResultSet resultSet = statement.executeQuery(sql);
        while (resultSet.next()){
            System.out.println(resultSet.getInt(1));
            System.out.println(resultSet.getString(2));
            System.out.println(resultSet.getString(3));
        }
    }
}

package com.sicheng.entity;


public class User {

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

    public User() {
    }

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

package com.sicheng.dao;

import com.sicheng.entity.User;

import java.util.List;

public interface UserMapper {

    List<User> selectUser();
}

<?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>
    <!-- 这里写配置内容 -->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <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;useSSL=false&amp;serverTimezone=GMT%2B8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/sicheng/dao/userMapper.xml"/>
    </mappers>
</configuration>

<?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">

<mapper namespace="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>
</mapper> 

package com.sicheng.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.InputStream;

public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static{
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = null;
            inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSession(){
        return sqlSessionFactory.openSession();
    }
}

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }
}

<![CDATA[
   内部的所有内容都会被解析器忽略
]]>

jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8

Reader getResoutceAsReader(String resource)

Stream getResourceAsStream(String resource)

File getResourceAsFile(String resource)

Properties getResourceAsProperties(String resource);

Url getResourceAsUrl(String resource)