我有一個一對多的關係的集合,這裏是我的代碼無法寫入內容:無法懶洋洋地初始化角色
@Entity
@Table(name = "catalog")
public class Catalog {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "catalog_id")
private int catalog_id;
@NotEmpty
@Size(min = 3, max = 255)
@Column(name = "name", nullable = false)
private String name;
@OneToMany(mappedBy="mycatalogorder")
private List<Order> orders;
@OneToMany(mappedBy="mycatalog")
private List<CatalogItem> items;
// setters and getters
}
@Entity
@Table(name = "catalogitem")
public class CatalogItem {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "catalogitem_id")
private int catalogitem_id;
@NotEmpty
@Size(min = 3, max = 255)
@Column(name = "name", nullable = false)
private String name;
@NotEmpty
@Column(name = "price", nullable = false)
private Double price;
@OneToOne(mappedBy="ordercatalogitem", cascade=CascadeType.ALL)
private OrderItem morderitem;
@ManyToOne
@JoinColumn(name="catalog_id", nullable=false)
private Catalog mycatalog;
// setters and getters
}
@Entity
@Table(name = "orders")
public class Order {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "order_id")
private int order_id;
@NotEmpty
@Size(min = 3, max = 255)
@Column(name = "name", nullable = false)
private String name;
@NotEmpty
@Size(min = 3, max = 1024)
@Column(name = "note", nullable = false)
private String note;
@Temporal(TemporalType.TIMESTAMP)
@DateTimeFormat(pattern = "ddmmYYYY HH:mm:ss")
@Column(name = "created", nullable = false)
private Date created;
@OneToMany(mappedBy="myorder")
private Set<OrderItem> orderItems;
@ManyToOne
@JoinColumn(name="catalog_id", nullable=false)
private Catalog mycatalogorder;
@PrePersist
protected void onCreate() {
created = new Date();
}
// setters and getters
}
@Entity
@Table(name = "orderitem")
public class OrderItem {
@Id
@Column(name="catalogitem_id", unique=true, nullable=false)
@GeneratedValue(generator="gen")
@GenericGenerator(name="gen", strategy="foreign", [email protected](name="property", value="catalogitem"))
private int catalogitem_id;
@Column(name = "quantity")
private int quantity;
@OneToOne
@PrimaryKeyJoinColumn
private CatalogItem ordercatalogitem;
@ManyToOne
@JoinColumn(name="order_id", nullable=false)
private Order myorder;
// setters and getters
}
而且我得到異常:
組織.springframework.http.converter.HttpMessageNotWritableException: 無法寫入內容:無法長時間初始化集合 角色:com.example.helios.model.Catalog.items,無法初始化 proxy - no Session;嵌套的例外是 com.fasterxml.jackson.databind.JsonMappingException:無法懶洋洋地初始化 角色的集合: com.example.helios.model.Catalog.items,無法初始化代理 - 無會話 org.springframework。 http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:271) org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:100) org.springframework.web.servlet.mvc.method.annotation。 AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:222) org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEnt ityMethodProcessor.java:183) org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:80) org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java: 126)
我的版本是:
- springframework的4.2.4.RELEASE
- 休眠4.3.11.Final
- 傑克遜2.7 0.4
- Jacksontype 2.7.1
謝謝,解決方案#1爲我工作。 – KostasC
解決方案#2爲我工作就像一個魅力!乾杯! –
但第二個解決方案是靜態的..在一個項目中,我們有時需要相關實體,有時不需要。這個EntityManager生命週期與春季完成的自動序列化是一個可怕的陷阱。 –