Java 使用spring jpa获取数据

我仍然是java和spring的初学者，我已经在mysql中存储了名为

的表，我正在尝试逐行获取数据
，其中状态==0
，我的表如下所示：

-------------+------------+------------+------------+--------------+--------+--------+--------+--------+--------------+
| 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   |
+-------------+------------+------------+------------+--------------+--------+--------+--------+--------

当我尝试运行代码时，它返回

org.springframework.beans.factory.BeanCreationException:错误
创建在类路径中定义了名为“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:未为实体指定标识符：
com.example.accessingdatajpa.Offers

提议

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;
    }
}

报价人仓库

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);
}

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());
    }
}

package com.example.accessingdatajpa；
导入静态org.assertj.core.api.Assertions.assertThat；
导入java.util.List；
导入org.junit.Test；
导入org.junit.runner.RunWith；
导入org.springframework.beans.factory.annotation.Autowired；
导入org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest；
导入org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager；
导入org.springframework.test.context.junit4.SpringRunner；
@RunWith（SpringRunner.class）
@DataJpaTest
公开类要约人报告测试{
@自动连线
私人测试管理者实体管理者；
@自动连线
私人要约；
@试验
公共无效testFindByStatus（）{
报价=新报价（）；
entityManager.persist（提供）；
List findByStatus=offer.findByStatus（offer.getStatus（））；
assertThat（findByStatus）.extracting（Offers:：getStatus）.containsOnly（Offer.getStatus（））；
}
}
提供没有主键。必须用@Id注释主键属性

像

你需要像这样做：

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

您缺少一个用
@Id
注释的字段。每个
@实体
都需要一个
@Id
——这是数据库中的主键。在实体类上指定注释，如：

@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注释的位置标记了持久性状态访问
标识符唯一地标识该表中的每一行。通过
默认情况下，假定表的名称与名称相同
实体的名称。显式给出表的名称或指定
关于表的其他信息，我们将使用
表注释。逻辑名称可以是
由用户指定（例如使用@Column或@Table），也可以
由Hibernate通过隐式命名策略隐式确定
合同

官方的。
我发现这里有不少错误：

1st

将
@Id
注释添加到
msisdn

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

第二名

将
@Repository
注释添加到
OffersRepository

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

    List<Offers> findByStatus(String Status);

    Offers findByMsisdn(String Msisdn);
}

@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("");
        };
    }

}

4th

如果要使用
CommandLineRunner
，则需要实现它。您可以用一种非常简单的方法来实现，只需在引导类中实现即可

访问datajpaaapplication.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("");
    }

}

您需要像@Id@GeneratedValue（strategy=GenerationType.AUTO）一样执行私有字符串Msisdn；每次运行代码时，它都会返回此警告：启动ApplicationContext时出错。要显示条件报告，请在启用“调试”的情况下重新运行应用程序。2019-10-16 16:13:01.855错误16835---[main]o.s.boot.SpringApplication:应用程序运行失败org.springframework.beans.factory.unsatifiedpendencyException:创建名为“demo”的bean时出错，该bean在com.example.accessingdatajpa.accessingdatajpaa应用程序中定义：通过方法“demo”参数0表示的未满足依赖关系；嵌套异常是在上下文初始化过程中遇到的org.springframework.beans.factorException-取消刷新尝试：org.springframework.beans.factory.UnsatisfiedDependencyException:创建名为“AccessingDataJPAAApplication”的bean时出错：通过字段“repository”表示的未满足依赖关系；嵌套异常为org.springframework.beans.factory.BeanCreationException:创建名为“OfferRepository”的bean时出错：调用init方法失败；嵌套异常为java.lang.IllegalArgumentException:未能为方法public abstract java.util.List com.example.accessingdatajpa.OffersRepository.findByStatus（java.lang.String）创建查询！按照约定，无法在此ManagedType[com.example.accessingdatajpa.Offers]上找到具有给定名称[status]的属性，属性通常以小写开头。将
Offers
类中的属性
Status
重命名为
Status
private String status
谢谢，它已经工作了，但问题是它没有在控制台well上打印结果，这是因为您没有在控制台上打印任何内容。如果要使用CommandLineRunner，则需要实现它。我已经更新了我的答案。你能帮我回答这个问题吗
@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("");
        };
    }

}

@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("");
    }

}