<dependency>
    <groupId>com.dameng</groupId>
    <artifactId>Dm8JdbcDriver18</artifactId>
    <version>8.1.1.49</version>
</dependency>

server.port=8082
server.servlet.context-path=/dm
serverTimezone=Asia/Shanghai
spring.datasource.driver-class-name=dm.jdbc.driver.DmDriver
spring.datasource.url=jdbc:dm://127.0.0.1:5236/demo?
spring.datasource.username=SYSDBA
spring.datasource.password=SYSDBA

mybatis.mapper-locations=classpath:dao/*.xml
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

@Data
public class User {
    private int id;
    private String name;
    private int age;
}

@Mapper
public interface UserDao {
    List<User> selectALL();
    Integer insertUser(User user);
}

public interface UserService {
    List<User> selectALL();
    int insertUser(User user);
}

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserDao userDao;

    @Override
    public List<User> selectALL() {
        List<User> users = userDao.selectALL();
        return users;
    }

    @Override
    public int insertUser(User user) {
        int i = userDao.insertUser(user);
        return i;
    }
}

<?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="com.example.dao.UserDao">
    
    <select id="selectALL" resultType="com.example.pojo.User">
        select * from "SYSDBA"."user"
    </select>

    <select id="insertUser">
        insert into "demo"."user"("id", "name", "age") VALUES(#{id}, #{name}, #{age});
    </select>
</mapper>

@RestController
public class UserController {
    @Autowired
    UserService userService;

    @RequestMapping("/User")
    public String user(){
        List<User> users = userService.selectALL();
        return users.toString();
    }
}

@SpringBootApplication
@MapperScan("com.example.dao")
public class Dm8Application {
    public static void main(String[] args) {
        SpringApplication.run(Dm8Application.class, args);
    }
}

package com.example;

import com.example.pojo.User;
import com.example.service.UserService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest

class Dm8ApplicationTests {
    @Autowired
    UserService userService;

    @Test
    void selectAll() {
        List<User> users = userService.selectALL();

        for (User user : users) {
            System.out.println(user.toString());
        }
    }
}