No 2. JPA(Hibernate) + MySql 5.x 整合

No 2. JPA(Hibernate) + MySql 5.x 整合

注意提前安装好MySQL服务才能继续，本节。

1. 创建目录结构

2. 新增 JPA ， MySql 依赖(pom.xml)

<!--mysql 依赖-->
<!--mysql依赖 与JPA 的依赖顺序会导致导包不成功-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.13</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

3. 更新配置文件（application.properties）

server.port=9527

# ============================== MySQL?? =============================================================================
spring.datasource.url = jdbc:mysql://127.0.0.1:3306/jwtdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = password
spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver

# =================================== JPA ===============================================================================
# Specify the DBMS
spring.jpa.database = MYSQL
# Show or not log for each sql query ???? sql ??
spring.jpa.show-sql = true
# Hibernate ddl auto (create, create-drop, update) ?? create ???create????????????????????????
spring.jpa.hibernate.ddl-auto = update
# Naming strategy
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.DefaultNamingStrategy
# stripped before adding them to the entity manager ????
#spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect

4. 完善项目结构

4.1 实体类基类

package com.lc.data.domain;

import lombok.Data;
import lombok.Getter;
import lombok.Setter;
import org.hibernate.annotations.GenericGenerator;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;
import org.springframework.format.annotation.DateTimeFormat;

import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;

/**
 * 抽象实体类
 */
@MappedSuperclass
@Data
@EntityListeners(AuditingEntityListener.class)
@Setter
@Getter
public abstract class BaseEntity implements Serializable {

    //https://www.jianshu.com/p/3b384e873232
    @Id
//    @GenericGenerator(name = "uuid-key", strategy = "uuid2")
    //自定义主键没搞通常
//    @GenericGenerator(name = "uuidKey" ,strategy = "com.lc.data.utils.MyUuidKeyGenerator") //自定UUid
    @GenericGenerator(name = "uuidKey" ,strategy = "org.hibernate.id.UUIDGenerator") // 框子已实现的主键策略
    @GeneratedValue(generator = "uuidKey")
    @Column(length = 36)
    private String id;

    @CreatedDate
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date createTime;

    @LastModifiedDate
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date updateTime;

}

4.1.1 创建实体类User

package com.example.createpj.data.entity.security;

import com.lc.data.domain.BaseEntity;
import lombok.Data;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import java.io.Serializable;

//@Data   //moke 测试？
@Entity(name = "user")
public class User extends BaseEntity {

    @Column(length = 32)
    public String name;

    @Column(length = 18)
    public String username;

    public Integer status;

}

4.2 创建对应的 dao，service,controller层

package com.example.createpj.data.service;

import com.example.createpj.data.entity.security.User;
import com.example.createpj.repository.UserRepository;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;


@Service
public class UserService {

    @Autowired
    UserRepository userRepository;

    public User saveUser(User user, Boolean isFlush) {
        return userRepository.save(user);
    }

    public List<User> findAll() {
        return userRepository.findAll();
    }

    public List<User> getByName(String name) {
        return userRepository.getByName(name);
    }

    public List<User> getByUsername(String username) {
        return userRepository.getByUsername(username);
    }


}

package com.example.createpj.repository;

import com.example.createpj.data.entity.security.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UserRepository extends JpaRepository<User, String> {

    List<User> getByName(String name);

    List<User> getByUsername(String username);

    List<User> findAll();

}

package com.example.createpj.data.utils;

import lombok.Getter;
import lombok.Setter;

@Setter
@Getter
public class Result {

    private int code = 200;
    private String msg = "操作成功";
    private Object data;

    public Result(int code,String msg){
        this.code = code;
        this.msg = msg;
    }

    public Result(Object data){
        this.data = data;
    }

}

package com.example.createpj.data.utils;

import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.IdentifierGenerator;

import java.io.Serializable;
import java.util.UUID;

/**
 * 自定义主键生成策略
 * com.lc.data.utils.MyIdGenerator IdentityGenerator
 */
public class MyUuidKeyGenerator implements IdentifierGenerator {

    @Override
    public Serializable generate(SharedSessionContractImplementor sharedSessionContractImplementor, Object o) throws HibernateException {
        return (Serializable)UUID.randomUUID().toString();
    }

}

package com.example.createpj;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

@SpringBootApplication
@EnableJpaAuditing      //使注解自动插入时间的注解生效 @CreatedDate @LastModifiedDate
public class CreatePjApplication {

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

}

5. 启动，并访问接口插入第一条数据

5.1 查看表是否新建成功

5.2 访问接口插入第一条数据

点击新增：localhost:9527/user/saveUser?username=12323491&name=测试过h1216

确认是否新增成功

本节结束。