关于Spring Boot对jdbc的支持问题

<?xml version="1.0" encoding="UTF-8"?>
<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">
    <parent>
        <artifactId>spring-boot-02</artifactId>
        <groupId>com.keafmd</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>spring-boot-08</artifactId>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- 解析jsp类库  -->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
        </dependency>

        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- JDBC-启动器, 默认的数据源 HikariCP -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <!-- JDBC-启动器, 默认的数据源 HikariCP -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>

    </dependencies>

</project>

server:
  port: 80

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/ssm-java1?useSSL=false
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: 18044229

package com.keafmd;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * Keafmd
 *
 * @ClassName: App08
 * @Description:
 * @author: 牛哄哄的柯南
 * @Date: 2021-04-08 11:48
 * @Blog: https://keafmd.blog.csdn.net/
 */


@SpringBootApplication
public class App08 {

    public static void main(String[] args) {
        SpringApplication.run(App08.class, args);
    }

}

package com.keafmd.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * Keafmd
 *
 * @ClassName: UserDao
 * @Description:
 * @author: 牛哄哄的柯南
 * @Date: 2021-04-08 11:47
 * @Blog: https://keafmd.blog.csdn.net/
 */
@Repository
public class UserDao {

    @Autowired
    JdbcTemplate jdbcTemplate;

    public List userList(){
        String sql ="select * from user";
        return jdbcTemplate.queryForList(sql);

    }
}

package com.keafmd.service;

import java.util.List;

/**
 * Keafmd
 *
 * @ClassName: IUserService
 * @Description:
 * @author: 牛哄哄的柯南
 * @Date: 2021-04-08 11:59
 * @Blog: https://keafmd.blog.csdn.net/
 */
public interface IUserService {

    List list();
}

package com.keafmd.service.impl;

import com.keafmd.dao.UserDao;
import com.keafmd.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * Keafmd
 *
 * @ClassName: UserServiceImpl
 * @Description:
 * @author: 牛哄哄的柯南
 * @Date: 2021-04-08 12:00
 * @Blog: https://keafmd.blog.csdn.net/
 */
@Service
public class UserServiceImpl implements IUserService {

    @Autowired
    UserDao userDao;

    @Override
    public List list() {
        return userDao.userList();
    }
}

package com.keafmd.controller;

import com.keafmd.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * Keafmd
 *
 * @ClassName: UserController
 * @Description:
 * @author: 牛哄哄的柯南
 * @Date: 2021-04-08 18:04
 * @Blog: https://keafmd.blog.csdn.net/
 */
@RestController
public class UserController {

    @Autowired
    IUserService userService;

    /**
     * http://127.0.0.1/userlist
     * @return
     */
    @RequestMapping("userlist")
    List UserList(){
        return userService.list();
    }
}

package com.keafmd.dao;

import com.keafmd.App08;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

@SpringBootTest(classes = App08.class)
class UserDaoTest {

    @Autowired
    UserDao userDao;

    @Test
    public void test(){
        List userlist = userDao.userList();
        for (Object o : userlist) {
            System.out.println(o);
        }
    }

}