小贝子编程

使用 Spring Data JPA 进行休眠一对一映射的堆栈溢出错误



我的问题与此类似 https://discourse.hibernate.org/t/hibernate-throws-org-hibernate-id-identifiergenerationexception-attempted-to-assign-id-from-null-one-to-one-property/1777 但是在应用此线程的答案后，我得到了不同的异常。

我的实体：

@Entity
@Table(name = "location")
public class Location {
@Id
private Long id;
@Column(name = "country_code")
private String countryCode;
private Double longitude;
private Double latitude;
@OneToOne(fetch = FetchType.LAZY)
@MapsId
private Distributor distributor;
public Distributor getDistributor() {
return distributor;
}
// here I apply the advice from the linked thread above
public void setDistributor(Distributor distributor) {
this.distributor = distributor;
this.id = distributor.getId();
}
// other getters/setters
}

@Entity
@Table
public class Distributor {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String site;
@OneToOne(
mappedBy = "distributor",
cascade = CascadeType.ALL,
orphanRemoval = true,
fetch = FetchType.LAZY,
optional = false
)
private Location location;
// getters/setters/constructor
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof Distributor )) return false;
Distributor that = (Distributor ) o;
return Objects.equals(id, that.id);
}
@Override
public int hashCode() {
return id != null ? id.hashCode() : 0;
}
}

带有相应 Spring 数据存储库的控制器：

@PostMapping
public ResponseEntity<Distributor> test(@RequestBody Distributor distributor) {
distributor.getLocation().setDistributor (distributor);
return ResponseEntity.ok(repository.save(distributor));
}

使用此有效负载：

{
"name" : "name1",
"location" : {
"countryCode" : "US",
"longitude" : 34 ,
"latitude" : 12
}
}

我得到了一个无休止的嵌套响应，其中包含正确的字段(分销商 -> 位置 -> 分销商 -> 位置 ..(，它以 SO 错误结尾：

java.lang.StackOverflowError: null
at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[na:na]
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016) ~[na:na]
at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174) ~[na:na]
at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:800) ~[na:na]
at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:698) ~[na:na]
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:621) ~[na:na]
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579) ~[na:na]
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:741) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
....

我无法理解为什么会发生这种情况，我遵循了所有可用的教程。

那是因为Location和Distributor之间存在循环依赖关系。

由于两者都相互引用，因此它们不断序列化内部引用。

您可以使用jackson注释@JsonBackReference和@JsonManagedReference来避免这种情况。

JsonBackReference：跳过带注释属性的序列化

JsonManagedReference ：前向引用和序列化带注释的属性

在您的情况下，这应该有效。

//Distributor class
@JsonManagedReference
private Location location;
//Location class 
@JsonBackReference
private Distributor distributor;

就我而言，我有两个实体相互关系，所以如果我创建其中一个的对象，我就会陷入某个无限的 JSON 共振循环。

我用@ManyToMany关系顶部的注释解决了这个问题@JsonIgnore例如：

@JsonIgnore
@ManyToMany(mappedBy = "drugs") 
private Set<Pharmacy> pharmacies;

和

@JsonIgnore
@ManyToMany(cascade = CascadeType.DETACH, fetch = FetchType.EAGER)
@JoinTable( name = "pharmacy_drug", joinColumns = @JoinColumn(name =
"pharmacy_id", referencedColumnName = "id"), inverseJoinColumns
= @JoinColumn(name = "drug_id", referencedColumnName = "id"))
private Set<Drug> drugs;

相关内容

最新更新


热门标签：

javascript python java c# php android html jquery c++ css ios sql mysql arrays asp.net json python-3.x ruby-on-rails .net sql-server django objective-c excel regex ruby linux ajax iphone xml vba spring asp.net-mvc database wordpress string postgresql wpf windows xcode bash git oracle list vb.net multithreading eclipse algorithm macos powershell visual-studio image forms numpy scala function api selenium