这是我第一次遇到这个问题。我有两个具有相互关系的实体 @OneToMany
和 @ManyToOne
。
团队实体:
@Entity
@Data
public class Team {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String image;
@OneToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER, mappedBy = "team")
private List<Player> playerList = new ArrayList<>();
}
玩家实体:
@Data
@Entity
public class Player {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String nickname;
@ManyToOne
private Team team;
}
我想实现在将玩家列表保存到团队后,玩家可以将该团队的记录接收到他们的表中。将团队设置为玩家后(所以我知道该玩家在团队中)并获取玩家列表,例如使用此 Controller :
@RestController
@RequestMapping("/api")
@RequiredArgsConstructor
public class PlayerController {
private final PlayerRepository playerRepository;
@GetMapping("/player")
public List<Player> getPlayers() {
return playerRepository.findAll();
}
}
我遇到了java.lang.StackOverflowError: null
:
2020-03-15 21:58:48.419 WARN 8576 --- [nio-8080-exec-2] .w.s.m.s.DefaultHandlerExceptionResolver : Failure while trying to resolve exception [org.springframework.http.converter.HttpMessageNotWritableException]
java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
[...]
2020-03-15 21:58:48.423 ERROR 8576 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Infinite recursion (StackOverflowError); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->[...] with root cause
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:737) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
**AND IT LOOPS OVER AND OVER**
它似乎遇到了某种循环,但我不知道为什么。我将非常感谢每一个帮助!
最佳答案
这个双向json映射问题将这些注释添加到您的实体对应字段
在播放器中:
@ManyToOne
@JsonManagedReference
private Team team;
在团队中:
@JsonBackReference
@OneToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER, mappedBy ="team")
private List<Player> playerList = new ArrayList<>();
请参阅此答案:
关于java - 堆栈溢出错误: null in both side relationship,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60697770/