本文講述的內(nèi)容是是在springboot 2.1.3.RELEASE和springdata 2.1.5.RELEASE的基礎(chǔ)上進(jìn)行的，開發(fā)工具為Spring Tool Suite，數(shù)據(jù)庫使用的是mysql。
1、創(chuàng)建一個springboot工程，添加jpa等依賴

image.png

2、配置數(shù)據(jù)源及JPA配置

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/jpa?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
    username: root
    password: 1234
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    properties:
      hibernate:
        format_sql: true

說明：
spring.jpa.hibernate.ddl-auto可選參數(shù) :
create 啟動時刪數(shù)據(jù)庫中的表，然后創(chuàng)建，退出時不刪除數(shù)據(jù)表 ;
create-drop 啟動時刪數(shù)據(jù)庫中的表，然后創(chuàng)建，退出時刪除數(shù)據(jù)表 如果表不存在報錯 ;
update 如果啟動時表格式不一致則更新表，原有數(shù)據(jù)保留 ;
validate 項目啟動表結(jié)構(gòu)進(jìn)行校驗 如果不一致則報錯;
建議使用update

3、創(chuàng)建實體類

@Entity
@Table(name="t_school")
public class School implements Serializable{

    private static final long serialVersionUID = 3624350753446288205L;
    
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer schoolId;
    
    private String schoolNo;
    
    private String schoolName;
    
    @Temporal(TemporalType.TIMESTAMP)
    private Date createDate;

    public Integer getSchoolId() {
        return schoolId;
    }

    public void setSchoolId(Integer schoolId) {
        this.schoolId = schoolId;
    }

    public String getSchoolNo() {
        return schoolNo;
    }

    public void setSchoolNo(String schoolNo) {
        this.schoolNo = schoolNo;
    }

    public String getSchoolName() {
        return schoolName;
    }

    public void setSchoolName(String schoolName) {
        this.schoolName = schoolName;
    }

    public Date getCreateDate() {
        return createDate;
    }

    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }

    @Override
    public String toString() {
        return "School [schoolId=" + schoolId + ", schoolNo=" + schoolNo + ", schoolName=" + schoolName + ", createDate=" + createDate + "]";
    }


}

@Entity表明為實體，@Table(name="t_class")指定數(shù)據(jù)庫表名，@Id用于指定主鍵，
@GeneratedValue指定主鍵生成策略，@Temporal用于指定日期類型
此處使用自動創(chuàng)建表

@RunWith(SpringRunner.class)
@SpringBootTest
public class Jpa3ApplicationTests {

    @Test
    public void contextLoads() {
    }

}

執(zhí)行SpringBoot Junit測試會自動創(chuàng)建表。
4、創(chuàng)建DAO

public interface SchoolRepository extends JpaRepository<School, Integer>{

}

JpaRepository為spring data封裝的類，其中包含了很多增刪改查的方法，實際開發(fā)過程中繼承這個類即可。
5、測試
新建：

    @Autowired
    private SchoolRepository schoolRepository;
    
    
    @Test
    public void insert() {
        School school = new School();
        school.setSchoolNo("S001");
        school.setSchoolName("第一中學(xué)");
        school.setCreateDate(new Date());
        schoolRepository.save(school);
    }

執(zhí)行結(jié)果：

image.png

查詢（jpa的查詢方式比較多，此處只做簡單演示）

    @Test
    public void select() {
        School school = schoolRepository.findById(1).get();
        System.out.println(school);
    }

執(zhí)行結(jié)果：

image.png

更新

    @Test
    public void testUpdate() {
        School school = schoolRepository.findById(1).get();
        school.setSchoolName("第一中學(xué)=====");
        schoolRepository.save(school);
        System.out.println(school);
    }

執(zhí)行結(jié)果：

image.png

刪除

    @Test
    public void testRemove() {
        schoolRepository.deleteById(1);
    }

執(zhí)行結(jié)果：

image.png

如果要輸出sql參數(shù)的話，增加如下日志配置：

logging:
  level:
    org.hibernate.type.descriptor.sql.BasicBinder: TRACE