springboot配置简单，直接用application.yml最好

yml语法，空格2个，冒号后面空格1个。不空，报错！！！

server:
  port: 8081
  servlet:
    context-path: /luckymoney

limit:
  minMoney: 0.01
  maxMoney: 9999
  description: 最少要发${limit.minMoney}元,最多${limit.maxMoney}元

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/luckymoney?characterEncoding=utf-8
    username: root
    password: passw@rd
  jpa:
    hibernate:
      ddl-auto: create
    show-sql: true

Luckymoney.java 类如何和mysql数据库通信

注意，不要引入错误的包！！！

package com.imooc.luckymoneyspringboot;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import java.math.BigDecimal;

/**
 * author:xuwen
 * Created on 2021/5/6
 */
@Entity
public class Luckymoney {
    @Id
    @GeneratedValue
    private Integer id;
    private BigDecimal money;
    private String producer;
    private String consumer;

    //无参空方法
    public Luckymoney(){}

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public BigDecimal getMoney() {
        return money;
    }

    public void setMoney(BigDecimal money) {
        this.money = money;
    }

    public String getProducer() {
        return producer;
    }

    public void setProducer(String producer) {
        this.producer = producer;
    }

    public String getConsumer() {
        return consumer;
    }

    public void setConsumer(String consumer) {
        this.consumer = consumer;
    }
}

截图参考：

准备mysql数据库，我新建了一个luckymoney库，luckymoney的表。

新建了一个LuckymoneyRespository的接口

package com.imooc.luckymoneyspringboot;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.JpaRepository;


//继承，JpaRepository，实体类，id类型
public interface LuckmoneyRepository extends JpaRepository<Luckymoney, Integer>{


}

在luckymoneyController类中写

package com.imooc.luckymoneyspringboot;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * author:xuwen
 * Created on 2021/5/6
 */
@RestController
public class LuckymoneyController {

    @Autowired
    private LuckmoneyRepository repository;
/**
 * 获取红包列表,查询数据库
 */
    @GetMapping("/luckymoneys")
    public List<Luckymoney> list(){
        return repository.findAll();
    }

}

结果：