使用 spring jpa 获取数据

Question

我还是java和spring的初学者，我已经在mysql中存储了名为Offers的表，我试图逐行获取数据where the Status == 0，我的表看起来像：

-------------+------------+------------+------------+--------------+--------+--------+--------+--------+--------------+
| Msisdn      | Entry_Date | Start_Date | End_Date   | Service_Type | Status | Parm_1 | Parm_2 | Parm_3 | Process_Date |
+-------------+------------+------------+------------+--------------+--------+--------+--------+--------+--------------+
| 7777777777  | 2019-01-11 | 2019-02-15 | 2019-03-03 | 1            |      1 | 1      | 1      | 1      | 2019-10-15   |
| 7888888899  | 2019-01-11 | 2019-02-12 | 2019-03-03 | 1            |      0 | 1      | 1      | 1      | 2019-10-15   |
| 799999999   | 2019-01-11 | 2019-02-10 | 2019-03-03 | 1            |      0 | 1      | 1      | 1      | 2019-10-15   |
| 79111111111 | 2019-01-28 | 2019-02-27 | 2019-03-03 | 1            |      0 | 1      | 1      | 1      | 2019-10-15   |
+-------------+------------+------------+------------+--------------+--------+--------+--------+--------

当我尝试运行我的代码时，它的返回

org.springframework.beans.factory.BeanCreationException: 错误 创建在类路径中定义的名称为“entityManagerFactory”的bean 资源 [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]： 调用 init 方法失败；嵌套异常是 org.hibernate.AnnotationException：没有为实体指定标识符： com.example.accessingdatajpa.Offers

优惠

package com.example.accessingdatajpa;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;


@Entity
public class Offers {

    @GeneratedValue(strategy=GenerationType.AUTO)
    private String Msisdn;
    private String Entry_Date;
    private String Start_Date;
    private String End_Date;
    private String Service_Type;
    private String Status;
    private String Parm_1;
    private String Parm_2;
    private String Parm_3;
    private String Process_Date;

    protected Offers() {}

    public Offers(String Msisdn, String Entry_Date, String Start_Date, String End_Date, String Service_Type, String Status, String Parm_1 ,String Parm_2, String Parm_3, String Process_Date) {
        this.Msisdn = Msisdn;
        this.Entry_Date = Entry_Date;
        this.Start_Date = Start_Date;
        this.End_Date = End_Date;
        this.Service_Type = Service_Type;
        this.Status = Status;
        this.Parm_1 = Parm_1;
        this.Parm_2 = Parm_2;
        this.Parm_3 = Parm_3;
        this.Process_Date = Process_Date;
    }

    @Override
    public String toString() {
        return String.format(
                "Offers[Msisdn='%s', Entry_Date='%s', Start_Date='%s', End_Date='%s', Service_Type='%s', Status='%s', Parm_1='%s', Parm_2='%s', Parm_3='%s',Process_Date='%s']",
                Msisdn, Entry_Date, Start_Date, End_Date, Service_Type, Status, Parm_1,Parm_2,Parm_3,Process_Date);
    }

    public String getMsisdn() {
        return Msisdn;
    }

    public String getProcess_Date() {
        return Process_Date;
    }

    public String getEntry_Date() {
        return Entry_Date;
    }

    public String getStart_Date() {
        return Start_Date;
    }

    public String getEnd_Date() {
        return End_Date;
    }

    public String getService_Type() {
        return Service_Type;
    }

    public String getStatus() {
        return Status;
    }

    public String getParm_1() {
        return Parm_1;
    }

    public String getParm_2() {
        return Parm_2;
    }

    public String getParm_3() {
        return Parm_3;
    }
}

OffersRepository

package com.example.accessingdatajpa;

import java.util.List;

import org.springframework.data.repository.CrudRepository;

public interface OffersRepository extends CrudRepository<Offers, String> {

    List<Offers> findByStatus(String Status);

    Offers findByMsisdn(String Msisdn);
}

访问DataJpaApplication

package com.example.accessingdatajpa;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class AccessingDataJpaApplication {

    private static final Logger log = LoggerFactory.getLogger(AccessingDataJpaApplication.class);

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

    @Bean
    public CommandLineRunner demo(OffersRepository repository) {
        return (args) -> {

            // fetch by status =0
            log.info("Offers found with findByStatus('0'):");
            log.info("--------------------------------------------");
            repository.findByStatus("0").forEach(on -> {
                log.info(on.toString());
            });
            log.info("");
        };
    }

}

测试文件

package com.example.accessingdatajpa;

import static org.assertj.core.api.Assertions.assertThat;

import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@DataJpaTest
public class OffersRepositoryTests {
    @Autowired
    private TestEntityManager entityManager;

    @Autowired
    private OffersRepository offer;

    @Test
    public void testFindByStatus() {
        Offers Offer = new Offers();
        entityManager.persist(Offer);

        List<Offers> findByStatus = offer.findByStatus(Offer.getStatus());

        assertThat(findByStatus).extracting(Offers::getStatus).containsOnly(Offer.getStatus());
    }
}

Answer 1

我发现那里的错误很少：

第一

给msisdn添加@Id注解

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private String Msisdn;

第二次

给OffersRepository添加@Repository注解

@Repository
public interface OffersRepository extends CrudRepository<Offers, String> {

    List<Offers> findByStatus(String Status);

    Offers findByMsisdn(String Msisdn);
}

第三次

将OffersRepository 类型的自动装配bean 添加到您的AccessingDataJpaApplication 类并从您的方法public CommandLineRunner demo(OffersRepository repository) 中删除参数OffersRepository repository

@SpringBootApplication
public class AccessingDataJpaApplication {

    private static final Logger log = LoggerFactory.getLogger(AccessingDataJpaApplication.class);

    @Autowired
    private OffersRepository repository;

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

    @Bean
    public CommandLineRunner demo() {
        return (args) -> {

            // fetch by status =0
            log.info("Offers found with findByStatus('0'):");
            log.info("--------------------------------------------");
            repository.findByStatus("0").forEach(on -> {
                log.info(on.toString());
            });
            log.info("");
        };
    }

}

第四次

如果你想使用CommandLineRunner，你需要实现它。您可以通过一种非常简单的方式来实现，只需在您的引导类中实现即可。

AccessingDataJpaApplication.java

@SpringBootApplication
public class AccessingDataJpaApplication implements CommandLineRunner {

    @Autowired
    private OffersRepository repository;

    private static final Logger log = LoggerFactory.getLogger(AccessingDataJpaApplication.class);

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

    @Override
    public void run(String...args) {
        log.info("Offers found with findByStatus('0'):");
        log.info("--------------------------------------------");
        repository.findByStatus("0").forEach(on - >{
            log.info(on.toString());
        });
        log.info("");
    }

}

Answer 2

优惠没有主键。您必须使用 @Id 注释主键属性

喜欢

@Id
private Integer id;

Answer 3

你需要这样做：

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private String Msisdn;

Answer 4

您缺少带有@Id 注释的字段。每个@Entity 都需要一个@Id - 这是数据库中的主键。在您的实体类上指定如下注释：

@Entity
@Table(name = "OFFERS")
public class Offers {

   @Id
   @GeneratedValue(strategy=GenerationType.AUTO)
   @Column(name = "Msisdn")
   private String Msisdn;

   @Column(name = "Entry_Date")   
   private String Entry_Date;

   @Column(name = "Start_Date")
   private String Start_Date;

   @Column(name = "End_Date")
   private String End_Date;

   @Column(name = "Service_Type")
   private String Service_Type;

   @Column(name = "Status")
   private String Status;

   @Column(name = "Parm_1")
   private String Parm_1;

   @Column(name = "Parm_2")
   private String Parm_2;

   @Column(name = "Parm_3")
   private String Parm_3;

   @Column(name = "Process_Date")
   private String Process_Date;
   //Setters and getters
}

如果您的列和表名遵循隐式命名策略，则可以不使用注释指定表和列。

@Id注解的放置标记持久化状态访问 strategy.The 标识符唯一标识该表中的每一行。经过 默认情况下，假设表的名称与名称相同 的实体。显式给出表的名称或指定 关于表的其他信息，我们将使用 javax.persistence.Table 注释。逻辑名称可以是显式的 由用户指定（例如使用@Column 或@Table），也可以是 Hibernate 通过 ImplicitNamingStrategy 隐式确定 合同。

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