Java 无法使用spring boot连接到mysql数据库

当我在Postman中点击url（）获取json数据时，它显示以下错误

{
    "timestamp": "2020-05-17T10:54:26.705+0000",
    "status": 404,
    "error": "Not Found",
    "message": "No message available",
    "path": "/pjt/samples"
}

1） pom.xml

3） 存储库

package repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import model.Sample;

@Repository
public interface SampleRepository  extends JpaRepository<Sample,Long>{

}

6） 应用程序属性

spring.datasource.url = jdbc:mysql://localhost:3306/sampledb?useSSL=false
spring.datasource.username = root
spring.datasource.password = dali

spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto = update

_ /\/“\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu\ （（））\ \/）| | | | | | | | |（| |） “| | | | | | | | | | | |，|/// =========|_|==============|___/=///_/ ：：弹簧靴：：（v2.2.7.版本）

2020-05-17 16:47:56.159信息3688---[main]com.example.demo.samplepjt应用程序：未设置活动配置文件，返回默认配置文件：默认
2020-05-17 16:47:58.395信息3688---[main].s.d.r.c.RepositoryConfigurationDelegate:在默认模式下引导Spring数据JPA存储库。
2020-05-17 16:47:58.476信息3688---[main].s.d.r.c.RepositoryConfigurationDelegate:Spring数据存储库扫描在49毫秒内完成。找到0个JPA存储库接口。
2020-05-17 16:48:00.119信息3688---[main]o.s.b.w.embedded.tomcat.TomcatWebServer:tomcat用端口初始化：8081（http）
2020-05-17 16:48:00.142信息3688---[main]o.apache.catalina.core.StandardService:启动服务[Tomcat]
2020-05-17 16:48:00.143信息3688---[main]org.apache.catalina.core.StandardEngine:启动Servlet引擎：[apache-Tomcat/9.0.34]
2020-05-17 16:48:00.496信息3688---[main]o.a.c.c.c.[Tomcat].[localhost].[/]：初始化Spring嵌入式WebApplicationContext
2020-05-17 16:48:00.497信息3688---[main]o.s.web.context.ContextLoader:根WebApplicationContext:初始化在4199毫秒内完成
2020-05-17 16:48:00.980信息3688---[main]o.hibernate.jpa.internal.util.LogHelper:hh000204:正在处理PersistenceUnitInfo[名称：默认值]
2020-05-17 16:48:01.156信息3688---[main]org.hibernate.Version:hh000412:hibernate ORM核心版本5.4.15.Final
2020-05-17 16:48:01.579信息3688---[main]o.hibernate.annotations.common.Version:HCANN000001:hibernate Commons annotations{5.1.0.Final}
2020-05-17 16:48:01.898信息3688---[main]com.zaxxer.hikari.HikariDataSource:hikaripol-1-开始…
2020-05-17 16:48:02.714信息3688---[main]com.zaxxer.hikari.HikariDataSource:hikaripol-1-启动完成。
2020-05-17 16:48:02.771信息3688---[main]org.hibernate.dialogue.dialogue:hh000400:使用方言：org.hibernate.dialogue.mysql5innodbdialogue
2020-05-17 16:48:03.635信息3688---[main]o.h.e.t.j.p.i.JtaPlatformInitiator:hh000490:使用JtaPlatform实现：[org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2020-05-17 16:48:03.660信息3688---[main]j.LocalContainerEntityManagerFactoryBean:为持久化单元“默认”初始化了JPA EntityManagerFactory
2020-05-17 16:48:04.042警告3688---[main]JpaBaseConfiguration$JpaWebConfiguration:spring.jpa.open-in-view默认启用。因此，可以在视图渲染期间执行数据库查询。显式配置spring.jpa.open-in-view以禁用此警告
2020-05-17 16:48:04.388信息3688---[main]o.s.s.concurrent.ThreadPoolTaskExecutor:初始化ExecutorService“applicationTaskExecutor”
2020-05-17 16:48:04.845信息3688---[main]o.s.b.w.embedded.tomcat.TomcatWebServer:tomcat已在端口8081（http）上启动，上下文路径为“”
2020-05-17 16:48:04.849信息3688---[main]com.example.demo.samplepjt应用程序：在9.906秒内启动samplepjt应用程序（JVM运行12.757）
2020-05-17 16:48:13.367信息3688---[nio-8081-exec-2]o.a.c.c.c.[Tomcat].[localhost].[/]：初始化Spring DispatcherServlet'DispatcherServlet'
2020-05-17 16:48:13.369信息3688---[nio-8081-exec-2]o.s.web.servlet.DispatcherServlet:初始化servlet“DispatcherServlet”
2020-05-17 16:48:13.395信息3688---[nio-8081-exec-2]o.s.web.servlet.DispatcherServlet:在25毫秒内完成初始化

---

有人能帮我解决这个问题吗？

您必须将

SampleController.java

放在

com.example.demo.controller

和

samplePository.java

中

com.example.demo.repository

。或者所有文件都应该在

com.example.demo

文件夹中

---

因为

@SpringBootApplication

必须扫描所有组件。仔细阅读此文档以便更好地理解。

组件扫描

将不会选择您的任何课程。将类/包移动到根包

com.example.demo

下。例如：

com.example.demo.controller

@SpringBootApplication

注释将当前包视为根包进行组件扫描，除非另有规定。或者您可以在@ComponentScan（basePackageClasses={model.Sample.class，repository.SampleRepository.clas，…}）中添加所有这些bean。但这不是一个好的解决方案，项目层次结构要好得多。

package repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import model.Sample;

@Repository
public interface SampleRepository  extends JpaRepository<Sample,Long>{

}

package controller;

import java.util.List;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import model.Sample;
import repository.SampleRepository;

@RestController
@RequestMapping("/pjt")
public class SampleController {

    @Autowired
    private SampleRepository sampleRepository;

     @PostMapping("/samples")
        public Sample createSample(@Valid @RequestBody Sample sample) {
            return sampleRepository.save(sample);
        }

     @GetMapping("/samples")
        public List<Sample> getAllSample() {
            return sampleRepository.findAll();
        }
    }

package com.example.demo;

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

@SpringBootApplication
public class SamplepjtApplication {

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

}

spring.datasource.url = jdbc:mysql://localhost:3306/sampledb?useSSL=false
spring.datasource.username = root
spring.datasource.password = dali

spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto = update