使用空 ID 保存实体 JPA

Question

我试图创建一个注册用户的功能。

@Service
public class RegistrationService {
    private AccountRepository accountRepository;
    private UserRepository userRepository;
    private final Logger logger = LogManager.getLogger(RegistrationService.class);
    
    public Boolean createNewUser(Registration registration) {
        User user = new User();
        user.setUserName(registration.getUserName());
        user.setPassword(registration.getPassword());
        logger.info("attempting to create user: {}", user);
        
        try {
            userRepository.save(user);          
        } catch(Exception e) {
            logger.error("Failed to register user: {}", e.getStackTrace());
            return false;
        }
        
        Account account = new Account();
        account.setUserId(user.getId());
        account.setBillingAddress(registration.getBillingAddress());
        account.setBillingCountry(registration.getBillingCountry());
        account.setBillingProvince(registration.getBillingProvince());
        account.setPhoneNumber(registration.getPhoneNumber());
        account.setZip(registration.getZip());
        logger.info("attempting to create account: {}", account);
        
        try {
            account = accountRepository.save(account);          
        } catch(Exception e) {
            logger.error("Failed to register account: {}", e.getStackTrace());
            return false;
        }
        
        
        return true;
    }
}

我遵循了这篇文章中的建议：将空作为id保存，并Hibernate，但解决方案对我不起作用。这是我的用户类

package com.company.app.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import lombok.Data;

@Entity
@Table(name="user")
@Data
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private String userName;

    private String password;

    
    public Long getId() {
        return this.id;
    }
    
    public void setUserName(String userName) {
        this.userName = userName;
    }
    
    public String getUserName() {
        return this.userName;
    }
    
    public void setPassword(String password) {
        this.password = password;
    }
    
    public String getPassword() {
        return this.password;
    }
}

这是我的账户类

package com.company.app.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import lombok.Data;

@Entity
@Table(name="account")
@Data
public class Account {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private Long userId;

    private String billingAddress;
    
    private String billingProvince;
    
    private String billingCountry;

    private String phoneNumber;

    private String zip;
    
    public Long getId() {
        return this.id;
    }
    
    public void setUserId(Long userId) {
        this.userId = userId;
    }

    public Long getUserId() {
        return userId;
    }

    public String getBillingAddress() {
        return billingAddress;
    }

    public void setBillingAddress(String billingAddress) {
        this.billingAddress = billingAddress;
    }

    public String getBillingProvince() {
        return billingProvince;
    }

    public void setBillingProvince(String billingProvince) {
        this.billingProvince = billingProvince;
    }

    public String getBillingCountry() {
        return billingCountry;
    }

    public void setBillingCountry(String billingCountry) {
        this.billingCountry = billingCountry;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getZip() {
        return zip;
    }

    public void setZip(String zip) {
        this.zip = zip;
    }
}

我的日志显示了以下输出

2021-04-14 14:40:09.265  INFO 15092 --- [nio-8080-exec-1] c.c.app.service.RegistrationService      : attempting to create user: User(id=null, userName=evan, password=test123)
2021-04-14 14:40:09.266 ERROR 15092 --- [nio-8080-exec-1] c.c.app.service.RegistrationService      : Failed to register user: com.company.app.service.RegistrationService.createNewUser(RegistrationService.java:26)

Answer 1

最后，ID需要一个值。< br >在您的例子中，ID被注释为@ generated value(strategy = generation type。IDENTITY)
这意味着您不必在程序中设置ID的值。< br >但是仍然需要一个值，因此DB必须负责设置ID。< br >例如，在mysql-table中，您可以通过将ID-Column定义为

`ID` bigint(20) NOT NULL AUTO_INCREMENT,

Answer 2

我猜你得到这个错误，因为你没有设置id。

尝试添加user.setId（registration.getId（））；