SpringBoot2.x整合jpa的配置使用

POM:

<?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>
    
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    
    <groupId>com.example</groupId>
    <artifactId>springboot-data-jpa</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-data-jpa</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-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.18</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
            <version>2.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.1.10.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.1.10.RELEASE</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

yml:

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://:3306/springjdbc
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

  jpa:
    hibernate:
      ddl-auto: update  # 更新或者创建数据表结构
    show-sql: true  # 控制台显示sql

实体类:

import lombok.Data;
import javax.persistence.*;

//配置映射关系,使用jpa注解
@Entity //告诉jpa这是一个实体类(和数据表映射的类)
@Table(name = "user")   //指定和哪个数据表对应,如果省略默认表名就是user
@Data
public class User {

    @Id //这是一个主键
    @GeneratedValue(strategy = GenerationType.IDENTITY) //自增主键
    private Integer id;

    @Column(name = "lastname") // 表中列名若有驼峰命名,使用该注解将驼峰字母小写
    private String lastName;

    @Column
    private String email;
}

user详情:

注意:

DAO:

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

// 继承Repository来完成对数据库操作
public interface UserRepository extends JpaRepository<User,Integer> {
}

Controller:

import com.example.springbootdatajpa.entity.User;
import com.example.springbootdatajpa.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.Optional;

@RestController
public class UserController {

    @Autowired
    UserRepository userRepository;

    @GetMapping("/user/{id}")
    public Optional<User> getUser(@PathVariable("id") Integer id){
        Optional<User> user = userRepository.findById(id);
        return user;
    }

    @GetMapping("/user")
    public User insertUser(User user){
        User save = userRepository.save(user);
        return save;
    }
}

测试:

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

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

GitHub:SpringBoot相关Demo