null 關系“技術”的“id”列中的值違反了非空約束 (PostgreSQL)

Question

Technology 和 technologyManager 類如下所示：我試圖通過 swagger-ui 將技術添加到數據庫，但在關系“technologies”的“id”列中出現 null 值的異常違反了非空約束

public class Technology {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private int id;

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

@ManyToOne(cascade = CascadeType.DETACH)
@JoinColumn(name = "language_id")
private ProgrammingLanguage language;
}

public void add(CreateTechnologyRequest technologyRequest) throws Exception {
    Technology technology = new Technology();
    
    
    if(technologyRequest.getName().isBlank()) {
        throw new Exception("Please enter a name");
    }else{
        for(Technology technologies : technologyRepository.findAll()) {
            if(technologies.getName().equalsIgnoreCase(technologyRequest.getName())) {
                throw new Exception("This name is already exist.");
            }else {
                
            }       technology.setName(technologyRequest.getName());    
                    
            for(ProgrammingLanguage language : languageRepository.findAll()) {
                
                if(language.getName().equalsIgnoreCase(technologyRequest.getLanguageName())) {
                    technology.setLanguage(language);
                }
            }           
        }
            technologyRepository.save(technology);
    }
    
}

我嘗試使用 swagger-ui 向數據庫添加一項新技術，但它在“id”列中拋出了 null 值的異常，即使它是主鍵並且是自動生成的。

Answer 1

嘗試使用GenerationType.AUTO而不是GenerationType.IDENTITY並將 id 的類型從int更改為Integer或Long