SpringBoot整合JPA方法及配置解析

<dependencies>
        <!-- lombok插件依赖 -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- mysql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
            <scope>runtime</scope>
        </dependency>
        <!-- jpa -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
    </dependencies>

import lombok.Data;
import org.hibernate.annotations.Comment;
//import org.hibernate.annotations.Table;
import javax.persistence.*;
/**
 * 人员
 */
@Data
@Entity
//@Table(appliesTo = "person",comment = "人员表")//appliesTo指表的名称（必填），MySQL表名小写，用Person会抛异常。
public class Person {
    @Id//主键标识
    @GeneratedValue(strategy = GenerationType.IDENTITY)//数据库主键策略，默认是AUTO。IDENTITY自增有符号主键
    @Comment("主键ID")//字段备注
    private Long id;
    @Column(name = "name",length = 20,unique = true,nullable = false)//字段属性设置
    @Comment("名称")
    private String name;
    @Comment("性别")
    private Integer sex;
    @Transient//此注解表示数据库不创建该字段
    private String ignore;//忽略字段
}

import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.List;
/**
 * 写法参考<a href="https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.query-creation" rel="external nofollow" />
 */
@Repository //不加也可以，只要你使用的时候注入即可。JpaRepository里面有很多简单的CRUD接口，可以少写很多代码。
public interface PersonRepository extends JpaRepository<Person, Long> {
	//根据名称精确查询
    List<Person> findByName(String name);//自定义方法
	//模糊查询
    List<Person> findByNameLike(String name);
	//分页模糊查询
    Page<Person> findAllByNameLike(String name, PageRequest pageRequest);
}

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import javax.annotation.Resource;
@Slf4j
@SpringBootTest
public class PersonRepositoryTests {
    @Resource
    private PersonRepository personRepository;
    /**
     * 新增/修改。一般情况下新增是不传ID的，只有修改才传ID。
     */
    @Test
    public void save(){
        Person person = new Person();
        person.setName("Meta39");
        person.setSex(0);
        this.personRepository.save(person);
        log.info("{}",this.personRepository.save(person));
    }
    /**
     * 查询
     */
    @Test
    public void search(){
//        log.info("{}",this.personRepository.findById(1L));//使用框架自带的方法
//        log.info("{}",this.personRepository.findByName("Meta"));//使用自定义根据名称查询方法
//        log.info("{}",this.personRepository.findByNameLike("%t%"));//使用自定义模糊查询方法
//        Page<Person> personPage = this.personRepository.findAll(PageRequest.of(0, 10, Sort.by(Sort.Direction.DESC, "id")));//分页查询
//        log.info("{}", personPage);//自带无参分页查询
        Page<Person> personPageByNameLike = this.personRepository.findAllByNameLike("%e%", PageRequest.of(0, 10, Sort.by(Sort.Direction.DESC, "id")));
        personPageByNameLike.forEach(System.out::println);//自定义模糊分页查询（%M%这种写法是不会有SQL注入的，不信自己可以试试%M% and id = 1）
    }
    /**
     * 删除
     */
    @Test
    public void delete(){
        this.personRepository.deleteById(1L);//根据ID删除一条记录
        this.personRepository.deleteAllById(Arrays.asList(1L,2L,3L));//根据ID集合批量删除记录
    }
}