springboot学习8 —— 整合 Spring Data JPA hibernate_spring-data-jpa 整合hibernate

从b站学习springcloud，现在进行总结，该总结除去了视频中出现的小错误，对有些易错的地方进行了提醒
b站链接：https://www.bilibili.com/video/av55993157
资料链接：
https://pan.baidu.com/s/1o0Aju3IydKA15Vo1pP4z5w
提取码: 21ru

上一节链接：https://blog.csdn.net/qq_40893824/article/details/106861955
下一节链接：https://blog.csdn.net/qq_40893824/article/details/106870713

下面的内容总结：
JPA hibernate 框架是 JPA 的1个实现，是 无sql语句的 mybatis

类似上1节，新建工程 springmybatis2
1 在 pom 文件中加入代码：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.southwind</groupId>
    <artifactId>springmybatis2</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-parent</artifactId>
        <version>2.1.5.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>
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2 在 java中创包 com.southwind.entity，其内新建实体类 Student，加入代码：

package com.southwind.entity;

import lombok.Data;

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

@Data
@Entity
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column
    private String name;
    @Column
    private double score;
    @Column
    private Date birthday;
}
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@Entity：映射 mysql 数据库中的表，语句用于 hibernate 的实体类
@Id：表示下面的数据类型是主键
@GeneratedValue(strategy = GenerationType.IDENTITY)：自增

3 在 southwind 中创包 repository，其内创建接口 StudentRepository，加入代码：
第1次用 JpaRepository 要自动下载很久…

package com.southwind.repository;

import com.southwind.entity.Student;
import org.springframework.data.jpa.repository.JpaRepository;

@Repository
public interface StudentRepository extends JpaRepository<Student,Long> {
    public Student getById(Long id);
}
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代码就是这么简单！
getById 由 Jpa 自动实现！

4 在 southwind 中 创包 controller，其内创建控制类 StudentHandler，加入代码：

package com.southwind.controller;

import com.southwind.entity.Student;
import com.southwind.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class StudentHandler {
    @Autowired
    private StudentRepository studentRepository;

    @PostMapping("/save")
    public Student save(@RequestBody Student student){
        return studentRepository.save(student);
    }

    @PutMapping("/update")
    public Student update(@RequestBody Student student){
        return studentRepository.save(student);
    }
    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id")long id){
        studentRepository.deleteById(id);
    }

    @GetMapping("/findAll")
    public List<Student> findAll(){
        return studentRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id")long id){
        return studentRepository.getById(id);
    }
}
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5 resources中创建 application.yml

加入代码：

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mbtest?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    show-sql: true
    properties:
      hibernate:
        format_sql: true
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6 在 southwind 中新建启动类 Application，加入代码：

package com.southwind;

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

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}
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7 启动 Application，测试

7.1 增加数据 post → http://localhost:8080/save


添加成功！

7.2 修改数据 put → http://localhost:8080/update


修改成功！

7.3 删除数据 deleById → http://localhost:8080/deleteById/8

删除成功！

7.4 按号查找 get → http://localhost:8080/findById/7

查找成功！

上一节链接：https://blog.csdn.net/qq_40893824/article/details/106861955
下一节链接：https://blog.csdn.net/qq_40893824/article/details/106870713