请求处理失败；嵌套异常org.springframework.dao.DataIntegrityViolationException：

Question

异常严重：Servlet。路径为[z2]的上下文中servlet[dispatcher]的service（）引发异常[请求处理失败；嵌套异常为org.springframework.dao.DataIntegrityViolationException:not null属性引用null或瞬时值：com.spring.entity.Product.cd；嵌套异常为org.hibernate.PropertyValueException:not null属性引用null或瞬时值：com.spring.entity.Product.cd]，根本原因为org.hibernate。PropertyValueException:not null属性引用null或瞬态值：com.spring.entity.Product。cd位于org.hibernate.engine.internal.Nullability.checkNullability（Nullability.java:106）位于org.hibernate.action.internal.AbstractEntityInsertAction.nullifyTransientReferencesIfNotAlready（AbstractEntityInsertAction.java:132）位于org.hibernate.action.internal.EntityIdentityInsertAction.execute（EntityIdentityInsertAction.java:86）位于org.hibernate.engine.spi.ActionQueue.execute（ActionQueue.java:490）org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction（ActionQueue.java:195）位于org.hibernate.engine.spi.ActionQueue.addInsertAction（ActionQueue.java:179）位于org.hibernate.engine.spi.ActionQueue.addAction（ActionQueue.java:214）位于org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction（AbstractSaveEventListener.java:324）org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate（AbstractSaveEventListener.java:288）位于org.hibernate.event.internal.AbstractSaveEventListener.performSave（AbstractSaveEventListener.java:194）位于org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId（AbstractSaveEventListener.java:125）位于org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId（JpaPersistEventListener.java:84）位于org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient（DefaultPersistEventListener.java:206）位于org.hibernate.event.internal.DefaultPersistEventListener.onPersist（DefaultPersistEventListener.java:149）org.hibernate.internal.DefaultPersistEventListener.onPersist（DefaultPersistEventListener.java:75）位于org.hibernate.internal.SessionImpl.firePersist（SessionImpl.java:811）位于org.hibernate.internal.SessionImpl.persist（SessionImpl.java:784）位于org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist（SessionImpl.java:789）（AbstractEntityManagerImpl.java:1181）位于java.base/jdk.internal.reflect.NativeMethodAccessorImpl。invoke0（本机方法）位于java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）位于java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）位于java.base/java.lang.reflect.Method.invoke（Method.java:566）位于org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvoke（SharedEntityManagerCreator.java:257）位于com.sun.proxy.Proxy39.persist（未知源）位于org.springframework.data.jpa.repository.support.SimpleJpaRepository.save（SimpleJpaRepository.java:431）位于java.base/jdk.internal.reflect.NativeMethodAccessorImpl。java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）at java.base/java.lang.reflect.Method.invoke（Method.java:566）

实体类

    @Entity
    @Table(name = "tbl_Customer")
    public class CustomerDetails {
    
        @Id
        @GeneratedValue
        @Column(name="Customer_Id")
        private Long custid;
    
        @Column(name="Customer_Name")
        private String customerName;
        
        @Column(name="Email")
        private String email;
        
        @Column(name="Address")
        private String address;
        
        @Column(name="Phone")
        private String phoneno;
        
        public CustomerDetails() {
        }
    
        @Override
        public String toString() {
            return "CustomerDetails [custid=" + custid + ", customername=" + customerName + ", email=" + email
                    + ", address=" + address + ", phoneno=" + phoneno + "]";
        }
    
        public CustomerDetails(String customername, String email, String address, String phoneno) {
            super();
            this.customerName = customername;
            this.email = email;
            this.address = address;
            this.phoneno = phoneno;
        }
    
        @OneToMany(mappedBy = "cd", fetch = FetchType.LAZY,cascade = CascadeType.ALL)
        private Set<Product> product;
        
    //getters and setters
    }
--------------------------------------------------------------------------------------------------

@Entity
@Table(name="tbl_Product")
public class Product {
 
    
    @Id
    @GeneratedValue
    @Column(name="Product_Id")
    private Long productId;
    
    @Column(name="Product_Name")
    private String productName;
    
    @Column(name="Product_Brand")
    private String productBrand;
    
    @Column(name="Product_Price")
    private double productPrice;
    
    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    private CustomerDetails cd;
   
    
    
    public Product(Long productId, String productName, String productBrand, double productPrice) {
        super();
        this.productId = productId;
        this.productName = productName;
        this.productBrand = productBrand;
        this.productPrice = productPrice;
    }
    
    
    
    public Product(String productName, String productBrand, double productPrice) {
        super();
        this.productName = productName;
        this.productBrand = productBrand;
        this.productPrice = productPrice;
    }

//getters and setters
}

Answer 1

我认为这是因为在映射设置中有option optional=false。此选项旨在防止运行时出现空值

@ManyToOne(fetch = FetchType.LAZY, optional = false)
private CustomerDetails cd;

optional=false的语义如下：

Whether the association is optional. If set to false then a non-null relationship must always exist.

因此，您应该检查对应实体的值是否为null