Java PropertyAccessException:调用setter时发生IllegalArgumentException

我将Spring3与JPA/Hibernate4一起使用。在尝试持久化“产品”实体时，我遇到了一个IllegalArgumentException。 我在Product和Category之间有一个一对多的关系，并且有一个复合键ProductId类，它只有Product和Category的PKs。我使用@IdClass注释，因为这两个PK都是由DB（MySql）自动生成的。 我下面的代码将更好地解释它

我的SQL脚本：

CREATE TABLE IF NOT EXISTS `orangeDB`.`Category` (
`catId` INT NOT NULL AUTO_INCREMENT,
`category` VARCHAR(45) NOT NULL,
`lft` INT NOT NULL,
`rgt` INT NOT NULL,
PRIMARY KEY (`catId`),
UNIQUE INDEX `categoryId_UNIQUE` (`catId` ASC))
ENGINE = InnoDB
AUTO_INCREMENT = 1795327;

CREATE TABLE IF NOT EXISTS `orangeDB`.`Product` (
`prodId` INT(9) NOT NULL AUTO_INCREMENT,
`prefix` CHAR NOT NULL,
`product` VARCHAR(45) NOT NULL,
`quantity` INT(9) NOT NULL,
`price` DOUBLE NOT NULL,
`discount` INT(9) NOT NULL,
`catId` INT NOT NULL,
PRIMARY KEY (`prodId`, `catId`),
INDEX `fk_Product_Category1_idx` (`catId` ASC),
CONSTRAINT `fk_Product_Category1`
  FOREIGN KEY (`catId`)
  REFERENCES `orangeDB`.`Category` (`catId`)
  ON DELETE CASCADE
  ON UPDATE CASCADE)
ENGINE = InnoDB
AUTO_INCREMENT = 1143713;

我的模型类：产品、类别和产品ID组合键类

@SuppressWarnings("serial")
@Entity
@Table(name = "Category", catalog = "orangeDB")
public class Category implements java.io.Serializable {

private Integer catId;
private String category;
private int lft;
private int rgt;
private Set<Product> products = new HashSet<Product>(0);

public Category() {
}

@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "catId", unique = true, nullable = false)
public Integer getCatId() {
    return this.catId;
}

public void setCatId(Integer catId) {
    this.catId = catId;
}

@Column(name = "category", nullable = false, length = 45)
public String getCategory() {
    return this.category;
}

public void setCategory(String category) {
    this.category = category;
}   

@OneToMany(fetch = FetchType.LAZY, mappedBy = "category")
public Set<Product> getProducts() {
    return this.products;
}

public void setProducts(Set<Product> products) {
    this.products = products;
}

public void addProduct(Product product) {
    this.products.add(product);
    if (product.getCategory() != this) {
        product.setCategory(this);
    }
}

// other getters and setters
}

@SuppressWarnings("serial")
@Entity
@IdClass(ProductId.class)
@Table(name = "Product", catalog = "orangeDB")
public class Product implements java.io.Serializable {

private Integer prodId;
private Category category;
private char prefix = 'P';
private String product;
private int quantity;
private double price;
private int discount;

public Product() {
}

 @Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "prodId", nullable = false)
public Integer getProdId() {
    return this.prodId;
}

public void setProdId(Integer prodId) {
    this.prodId = prodId;
}

@Id
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "catId", referencedColumnName = "catId", nullable = false, insertable = false, updatable = false)
public Category getCategory() {
    return this.category;
}

public void setCategory(Category category) {
    this.category = category;       
}   

@Column(name = "product", nullable = false, length = 45)
public String getProduct() {
    return this.product;
}

public void setProduct(String product) {
    this.product = product;
}

// other getters and setters
}

@SuppressWarnings("serial")
public class ProductId implements java.io.Serializable {

private Integer prodId;
private Integer category;

public ProductId() {
}

public ProductId(Integer prodId, Integer category) {
    this.prodId = prodId;
    this.category = category;
}


public Integer getProdId() {
    return this.prodId;
}

public void setProdId(Integer prodId) {
    this.prodId = prodId;
}


public Integer getCategory() {
    return this.category;
}

public void setCategory(Integer category) {
    this.category = category;
}

public boolean equals(Object other) {
    if ((this == other))
        return true;
    if ((other == null))
        return false;
    if (!(other instanceof ProductId))
        return false;
    ProductId castOther = (ProductId) other;

    return (this.getProdId() == castOther.getProdId())
            && (this.getCategory() == castOther.getCategory());
}

public int hashCode() {
    int result = 17;

    result = 37 * result + this.getProdId();
    result = 37 * result + this.getCategory();
    return result;
}

}

谁能帮我把这件事做好吗？我参考了一些博客和Java持久性wikibooks，映射似乎很好。我不明白为什么会发生这种异常

编辑

哦，我忘了添加堆栈跟踪。给你

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: IllegalArgumentException occurred while calling setter of model.ProductId.prodId
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:965)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: IllegalArgumentException occurred while calling setter of model.ProductId.prodId
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310)
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1316)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:881)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:241)
$Proxy32.persist(Unknown Source)
service.ProductServiceImpl.save(ProductServiceImpl.java:42)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
$Proxy35.save(Unknown Source)
controller.Admincontroller.addProduct(Admincontroller.java:276)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

org.hibernate.PropertyAccessException: IllegalArgumentException occurred while calling setter of model.ProductId.prodId
org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:119)
org.hibernate.mapping.Component$ValueGenerationPlan.execute(Component.java:423)
org.hibernate.id.CompositeNestedGeneratedValueGenerator.generate(CompositeNestedGeneratedValueGenerator.java:121)
org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:78)
org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:208)
org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:151)
org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:78)
org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:853)
org.hibernate.internal.SessionImpl.persist(SessionImpl.java:827)
org.hibernate.internal.SessionImpl.persist(SessionImpl.java:831)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:875)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:241)
$Proxy32.persist(Unknown Source)
service.ProductServiceImpl.save(ProductServiceImpl.java:42)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
$Proxy35.save(Unknown Source)
controller.Admincontroller.addProduct(Admincontroller.java:276)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.IllegalArgumentException: argument type mismatch
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:65)
org.hibernate.mapping.Component$ValueGenerationPlan.execute(Component.java:423)
org.hibernate.id.CompositeNestedGeneratedValueGenerator.generate(CompositeNestedGeneratedValueGenerator.java:121)
org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:78)
org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:208)
org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:151)
org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:78)
org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:853)
org.hibernate.internal.SessionImpl.persist(SessionImpl.java:827)
org.hibernate.internal.SessionImpl.persist(SessionImpl.java:831)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:875)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:241)
$Proxy32.persist(Unknown Source)
service.ProductServiceImpl.save(ProductServiceImpl.java:42)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
$Proxy35.save(Unknown Source)
controller.Admincontroller.addProduct(Admincontroller.java:276)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

---

编辑2:从ProductId类中删除了@IdClass注释。

我认为在ProductId类中不需要@IdClass。只有在使用此复合id的实体中才需要它。此特定错误是由于您尝试使用integer，但必须使用ProductId类。这样试试

@SuppressWarnings("serial")
@Entity
@IdClass(ProductId.class)
@Table(name = "Product", catalog = "orangeDB")
public class Product implements java.io.Serializable {    
    private Integer prodId;
    private Category category;
    private char prefix = 'P';
    private String product;
    private int quantity;
    private double price;
    private int discount;

    @Id
    @Column(name = "prodId", nullable = false)
    public Integer getProdId() {
        return this.prodId;
    }

    public void setProdIt(Integer prodId) {
        this.prodId = prodId;
    }


    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "catId", referencedColumnName = "catId", nullable = false, insertable = false, updatable = false)
    public Category getCategory() {
        return this.category;
    }

    public setProductId(ProductId productId){
        this.prodId = productId.getProdId();
        this.category = productId.getCategory();
    }

    //getter&setters
}

在ProductId类中：

private Integer prodId;
private Category category;

public ProductId(Integer prodId, Category category) {
    this.prodId = prodId;
    this.category = category;
}

getters&setters

然后将其设置为：

Category category = new Category();
ProductId pId = new ProductId(1, category); //id, category
product.setProductId(pId);

也可以试试这个：

new Product(1, category); // pls add this constructor

您忽略这一点的主要原因可能是Produt中的setter和IdClass ProductId具有相似的名称

---

如果od使用IdClass，则不需要任何@GeneratedValue注释。

如果要使用

@IdClass

，则

ProductId

类和

Product

实体中的属性名称和类型必须匹配

在

Product.java

类中，您声明了：

prodId

as

Integer

和

category

as

category

但是在

ProductId.java

类中，您声明：

prodId

as

Integer

和

category

as

Integer

另外，您不应该在

ProductId

类中有

@IdClass

声明，您必须删除该声明

尝试以下更改：

Product.java

@Entity
@IdClass(ProductId.class)
@Table(name = "Product")
public class Product implements java.io.Serializable {

    private Integer prodId;
    private Category category;
    private int categoryId; // Adding new property

    @Id
    @GeneratedValue
    @Column(name = "prodId", nullable = false)
    public Integer getProdId() {
        return this.prodId;
    }

    @Id
    @Column(name = "catId", insertable = false, updatable = false)
    public int getCategoryId() {
        return categoryId;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "catId", referencedColumnName = "catId", nullable = false, insertable = false, updatable = false)
    public Category getCategory() {
        return this.category;
    }

// Remove the @IdClass annoatation from here
public class ProductId implements java.io.Serializable {

    private Integer prodId;
    private Integer categoryId; // The property name should match

    public ProductId() {
    }

    public ProductId(Integer prodId, Integer categoryId) {
        this.prodId = prodId;
        this.categoryId = categoryId;
    }

    public Integer getProdId() {
        return this.prodId;
    }

    public void setProdId(Integer prodId) {
        this.prodId = prodId;
    }

    public Integer getCategoryId() {
        return categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }

    public boolean equals(Object other) {
        if ((this == other))
            return true;
        if ((other == null))
            return false;
        if (!(other instanceof ProductId))
            return false;
        ProductId castOther = (ProductId) other;

        return (this.getProdId() == castOther.getProdId())
                && (this.getCategoryId() == castOther.getCategoryId());
    }

    public int hashCode() {
        int result = 17;

        result = 37 * result + this.getProdId();
        result = 37 * result + this.getCategoryId();
        return result;
    }

}

//二传手和接球手 }

ProductId.java

@Entity
@IdClass(ProductId.class)
@Table(name = "Product")
public class Product implements java.io.Serializable {

    private Integer prodId;
    private Category category;
    private int categoryId; // Adding new property

    @Id
    @GeneratedValue
    @Column(name = "prodId", nullable = false)
    public Integer getProdId() {
        return this.prodId;
    }

    @Id
    @Column(name = "catId", insertable = false, updatable = false)
    public int getCategoryId() {
        return categoryId;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "catId", referencedColumnName = "catId", nullable = false, insertable = false, updatable = false)
    public Category getCategory() {
        return this.category;
    }

// Remove the @IdClass annoatation from here
public class ProductId implements java.io.Serializable {

    private Integer prodId;
    private Integer categoryId; // The property name should match

    public ProductId() {
    }

    public ProductId(Integer prodId, Integer categoryId) {
        this.prodId = prodId;
        this.categoryId = categoryId;
    }

    public Integer getProdId() {
        return this.prodId;
    }

    public void setProdId(Integer prodId) {
        this.prodId = prodId;
    }

    public Integer getCategoryId() {
        return categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }

    public boolean equals(Object other) {
        if ((this == other))
            return true;
        if ((other == null))
            return false;
        if (!(other instanceof ProductId))
            return false;
        ProductId castOther = (ProductId) other;

        return (this.getProdId() == castOther.getProdId())
                && (this.getCategoryId() == castOther.getCategoryId());
    }

    public int hashCode() {
        int result = 17;

        result = 37 * result + this.getProdId();
        result = 37 * result + this.getCategoryId();
        return result;
    }

}

---

此更改还将解决与组合标识符不能为null有关的问题。请添加整个stacktrace。它不起作用。仍然显示相同的异常。我从ProductId类中删除了@IdClass注释。Product类中的setProdId（）方法采用整数。因此，如果我传递ProductId的实例，编译器会给出一个错误。所以我尝试将Product中的prodId字段从Integer类型更改为ProductId类型，然后按照您所说的做了，但它给出了相同的异常。我认为现在应该可以工作了。看看编辑过的版本。最重要的一点是，ProductId的字段中应该有Category，因为它是ProductId类的一部分。谢谢您的回复。但我想我不明白你的答案。setProdId（）方法接受Integer类型的参数。但是在您的解决方案中，您正在将类型为ProductId的pId传递到setProdId（）中。编译器出错。抱歉，我写得太匆忙了。现在，它应该更具体一些。但想法是一样的。在您的IdClass中，类别不能为int，因为它在product中属于category类型，并且被标记为@Id.Uff…我仍然无法从背后获得此异常。我不知道ProductId的这个setter方法有什么问题。我完全按照你说的做了，但还是有同样的例外。有没有办法避免使用复合密钥而只使用一个PK？没有用。但我认为这删除了“复合标识符不能为null”的异常。我通过注释掉将prodId设置为1122的语句进行了检查，它没有显示标识符异常。但是ProductId的setter上仍然出现IllegalArgumentException。@OhHaNi，你能发布完整的错误堆栈跟踪吗？你的问题没有完整的错误消息。我已经编辑了我的问题并添加了完整的堆栈跟踪。你可以问更多你想要的细节。