java.lang.IllegalStateException：org.hibernate.TransientPropertyValueException [英] java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException

问题描述

我的应用程序有两个实体产品和类别。添加产品时，用户选择产品所属的类别。但是，当将产品保存到数据库时，我遇到了错误。

org.springframework.web.util.NestedServletException：请求处理失败;嵌套的异常是java.lang.IllegalStateException：org.hibernate.TransientPropertyValueException：非空属性引用一个瞬态值 - 在当前操作之前必须保存瞬态实例

实体的内容是
Category.java

  @Entity 
 @Table ）
 public class Category {
 
 @Id 
 @GeneratedValue（strategy = GenerationType.AUTO）
私人长ID; 
 
 @Column（name =category_name）
 private String categoryName; 
 
 @Column（name =description）
私有字符串描述; 
 
 @OneToMany（mappedBy =category，fetch = FetchType.LAZY）
 private Set< Product>产品; 
 
 // getter and setter method 
} 
  

java

  @Entity 
 @Table（name =product）
 public class Product {
 
 @Id 
 @GeneratedValue（strategy = GenerationType.AUTO）
私人长ID; 
 
 @Column（name =name）
 @NotNull 
 @NotEmpty 
私人字符串名称; 
 
 @Column（name =description）
私有字符串描述; 
 
 @Column（name =manufacture）
私人字符串制造; 
 
 @Column（name =price）
私人长仓; 
 
 @Column（name =image_name）
 private String imageName; 
 
 @ManyToOne 
 @JoinColumn（name =category_id，referencedColumnName =id，nullable = false）
 Category category; 
 
 // getter and setter method 
} 
  

ProductDAO。 java

  @Repository（ProductDAO）
 @Transactional 
 public class ProductDAO {
 
 @PersistenceContext 
私人EntityManager entityManager; 
 
 public EntityManager getEntityManager（）{
 return entityManager; 
} 
 
 public void setEntityManager（EntityManager entityManager）{
 this.entityManager = entityManager; 
} 
 
 public void create（Product product）{
 entityManager.merge（product.getCategory（））; 
 entityManager.persist（product）; 
} 
 //其他方法
} 
  

我的jsp文件

 < form：form method =postcommandName =productaction =add.htmlenctype =multipart /格式数据> 
 Productname< form：input path =name/> 
< form：errors path =nameclass =error/>< br> 
 description< form：input path =description/>< br> 
 price< form：input path =price/>< br> 
制造< form：input path =manufacture/>< br> 
 Category 
< form：select path =category> 
< form：options items =$ {categories}itemValue =iditemLabel =categoryName/> 
< / form：select> 
< form：errors path =categoryclass =error/>< br> 
< br /> 
产品图片< input type =filename =file/> 
< form：errors path =imageNameclass =error/>< br> 
< input type =submitclass =registervalue =Save> 
< / form：form> 
  

我的转换器

  public class CategoryConverter implements Converter< String，Category> {
 
 @Autowired 
 private CategoryService categoryService; 
 
 public类型转换（String id）{
返回categoryService.findById（Long.valueOf（id））; 
} 
} 
  

感谢任何帮助

解决方案

请将（Cascade = CascadeType.ALL）添加到产品的类别字段映射中

  @ManyToOne（cascade = CascadeType.ALL）
 @JoinColumn（name =category_id，referencedColumnName =id，nullable = false）
 Category category; 
  

并在ProductDAO中移除此行：

  entityManager.merge（product.getCategory（））; 
  

注意：如果您的产品类别是现有的类别，则应先加载它，然后将其设置为您的产品，这是正常的流量。不要新建重复的Category对象。

My application has two entity Product and Category. When add product , user choose the category that product belong to. But when save the product to data base i meet the error

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation

the content of entity is Category.java

@Entity
@Table(name="category")
public class Category {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private long id;

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

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

@OneToMany(mappedBy = "category", fetch=FetchType.LAZY)
private Set<Product> products;

//getter and setter method
}

Product.java

@Entity
@Table(name="product")
public class Product {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private long id;

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

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

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

@Column(name="price")
private long price;

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

@ManyToOne
@JoinColumn(name = "category_id", referencedColumnName = "id", nullable = false)
Category category;

//getter and setter method
}

ProductDAO.java

@Repository("ProductDAO")
@Transactional
public class ProductDAO {

@PersistenceContext
private EntityManager entityManager;

public EntityManager getEntityManager() {
    return entityManager;
}

public void setEntityManager(EntityManager entityManager) {
    this.entityManager = entityManager;
}

public void create(Product product) {
    entityManager.merge(product.getCategory());
    entityManager.persist(product);
}
//other method
}

my jsp file

<form:form method="post" commandName="product" action="add.html" enctype="multipart/form-data">
    Productname <form:input path="name"/>
                <form:errors path="name" class ="error"/><br>
    description    <form:input   path="description"/><br>
    price    <form:input   path="price"/><br>
    manufacture <form:input path="manufacture"/><br>
    Category
    <form:select path="category">
    <form:options items="${categories}" itemValue="id" itemLabel="categoryName" />
    </form:select>
    <form:errors path="category" class ="error"/><br>
    <br/>
    Product image<input type="file" name="file" />
    <form:errors path="imageName" class ="error"/><br>
    <input type="submit" class="register" value="Save">
</form:form>

my Converter

public class CategoryConverter implements Converter<String, Category>{

    @Autowired
    private CategoryService categoryService;

    public Category convert(String id) {
        return categoryService.findById(Long.valueOf(id));
    }
}

thank for any help

解决方案

please add (cascade=CascadeType.ALL) into category field mapping of Product

@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name = "category_id", referencedColumnName = "id", nullable = false)
Category category;

and remove this line in ProductDAO:

entityManager.merge(product.getCategory());

NOTE: if your product's category is an existing one, you should load it first then set it to your product, this is normal flow. Do not new duplicated Category object.

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