java - 无法使用spring boot连接到mysql数据库
问题描述
当我在 Postman 中点击 url( http://localhost:8080/pjt/samples ) 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
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.7.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>samplepjt</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>samplepjt</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2)型号:
package model;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "samples")
public class Sample {
private Long id ;
private String name;
private String city;
public Sample(String name, String city) {
this.name = name;
this.city = city;
}
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
@Column(name = "name", nullable = false)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Column(name = "city", nullable = false)
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
@Override
public String toString() {
return "Sample [id=" + id + ",name=" + name + ", city=" + city + "]";
}
}
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>{
}
4)控制器
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();
}
}
5)主要功能
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);
}
}
6)application.properties
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
. ____ _ __ _ _ /\ / ' __ _ ( )_ __ __ _ \ \ \ \ ( ( )_ | '_ | ' | | ' / ` | \ \ \ \ \/ )| | )| | | | | || ( | | ) ) ) ' |____| . | | | | | | __, | / / / / =========|_|==============|___/=/ / /_/ :: Spring Boot :: (v2.2.7.发布)
2020-05-17 16:47:56.159 INFO 3688 --- [main] com.example.demo.SamplepjtApplication:未设置活动配置文件,回退到默认配置文件:默认
2020-05-17 16:47:58.395 INFO 3688 --- [main] .sdrcRepositoryConfigurationDelegate : 在默认模式下引导 Spring Data JPA 存储库。
2020-05-17 16:47:58.476 INFO 3688 --- [main] .sdrcRepositoryConfigurationDelegate:在 49 毫秒内完成 Spring 数据存储库扫描。找到 0 个 JPA 存储库接口。
2020-05-17 16:48:00.119 INFO 3688 --- [main] osbwembedded.tomcat.TomcatWebServer:Tomcat 使用端口初始化:8081 (http)
2020-05-17 16:48:00.142 INFO 3688 -- - [主] o.apache.catalina.core.StandardService:启动服务 [Tomcat]
2020-05-17 16:48:00.143 INFO 3688 --- [main] org.apache.catalina.core.StandardEngine:启动 Servlet 引擎:[Apache Tomcat/9.0.34]
2020-05-17 16:48:00.496 INFO 3688 --- [main] oaccC[Tomcat].[localhost].[/]:初始化 Spring 嵌入式 WebApplicationContext
2020-05-17 16:48:00.497 INFO 3688 --- [main] osweb.context.ContextLoader:根WebApplicationContext:初始化在 4199 毫秒内完成
2020-05-17 16:48:00.980 INFO 3688 --- [main] o.hibernate.jpa.internal.util.LogHelper:HHH000204:处理 PersistenceUnitInfo [名称:默认值]
2020-05- 17 16:48:01.156 INFO 3688 --- [main] org.hibernate.Version:HHH000412:Hibernate ORM 核心版本 5.4.15.Final
2020-05-17 16:48:01.579 INFO 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 --- [主] com.zaxxer.hikari.HikariDataSource :HikariPool-1 - 开始...
2020-05-17 16:48:02.714 信息 3688 --- [主] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - 启动完成。
2020-05-17 16:48:02.771 INFO 3688 --- [main] org.hibernate.dialect.Dialect:HHH000400:使用方言:org.hibernate.dialect.MySQL5InnoDBDialect
2020-05-17 16:48:03.635 INFO 3688 --- [main] ohetjpiJtaPlatformInitiator:HHH000490:使用 JtaPlatform 实现:[org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2020-05-17 16: 48:03.660 信息 3688 --- [主] j.LocalContainerEntityManagerFactoryBean:为持久性单元“默认”初始化 JPA EntityManagerFactory
2020-05-17 16:48:04.042 警告 3688 --- [主] JpaBaseConfiguration$JpaWebConfiguration:spring.jpa。默认情况下启用在视图中打开。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 INFO 3688 --- [main] ossconcurrent.ThreadPoolTaskExecutor:初始化 ExecutorService 'applicationTaskExecutor'
2020-05-17 16:48:04.845 INFO 3688 --- [main] osbwembedded.tomcat.TomcatWebServer :Tomcat 在端口上启动:8081 (http),上下文路径为 ''
2020-05-17 16:48:04.849 INFO 3688 --- [main] com.example.demo.SamplepjtApplication:在 9.906 秒内启动 SamplepjtApplication ( JVM 为 12.757 运行)
2020-05-17 16:48:13.367 INFO 3688 --- [nio-8081-exec-2] oaccC[Tomcat].[localhost].[/]:初始化 Spring DispatcherServlet 'dispatcherServlet'
2020- 05-17 16:48:13.369 INFO 3688 --- [nio-8081-exec-2] osweb.servlet.DispatcherServlet:初始化 Servlet '调度程序Servlet'
2020-05-17 16:48:13.395 INFO 3688 --- [nio-8081-exec-2] osweb.servlet.DispatcherServlet:在 25 毫秒内完成初始化
谁能帮我解决这个问题?
解决方案
你必须把SampleController.java
in com.example.demo.controller
& SampleRepository.java
in 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。阅读此文档以更好地理解https://docs.spring.io/spring-boot/docs/2.0.0.RELEASE/reference/html/using-boot-structuring-your-code.html。
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