Java框架spring Boot學習筆記（四）：Spring Boot操作MySQL數據庫

在pom.xml添加一下代碼，添加操作MySQL的依賴jar包。

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

<dependency>
　　<groupId>mysql</groupId>
　　<artifactId>mysql-connector-java</artifactId>
</dependency>

 

新建dbpeople的一個數據庫,用戶名root，密碼123456

 

修改application.yml文件

spring:
  profiles:
    active: prod
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/dbpeople
    username: root
    password: 123456
  jpa:
    hibernate:
      ddl-auto: create #update
    show-sql: true

 

添加一個people類People.java

package com.example.demo;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

//@Entity對應數據庫中的一個表
@Entity
public class People {

    //@Id配合@GeneratedValue，表示id自增長
    @Id
    @GeneratedValue
    private Integer id;
    private String name;
    private Integer age;

    //必須要有一個無參的構造函數，不然數據庫會報錯
    public People() {
    }

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

 

運行報錯：

Thu Nov 16 10:29:29 CST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

是因為高版本的MySQL連接需要useSSL=true，在application.yml文件中修改MySQL連接的url為

url: jdbc:mysql://localhost:3306/dbpeople?useSSL=true

 

運行成功刷新數據庫發現生成了一個people的表

 

在application.yml中的ddl-auto設置為create表示每次運行都會刪掉以前的表，再建一張新表

jpa:
    hibernate:
        ddl-auto: create 
        show-sql: true        

如果設置成update，如果已經有表不會刪掉原來的表，如果沒有則新建一張表。

jpa:
    hibernate:
        ddl-auto: update
        show-sql: true