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无限递归与Jackson JSON，Spring MVC 4.2和Hibernate JPA问题

问题内容：

当Spring MVC尝试通过jackson 2.6.1将具有双向关联的JPA对象转换为JSON时，我不断

org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Infinite recursion (StackOverflowError)

第一个实体是：

import com.fasterxml.jackson.annotation.JsonManagedReference;
import javax.persistence.Entity;
import javax.persistence.Table;
...

@Entity
@Table(name = "user")
public class User implements java.io.Serializable {
    private Integer userId;
    @JsonManagedReference
    private UserClass userClass;

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

@ManyToOne()
@JoinColumn(name = "userClassId")

public UserClass getUserClass() {
    return this.userClass;
}
.......
}

第二个是：

 import com.fasterxml.jackson.annotation.JsonManagedReference;
 import javax.persistence.Entity;
 import javax.persistence.Table;
 ...

@Entity
@Table(name = "user_class")
public class UserClass implements java.io.Serializable {

private Integer userClassId;
@JsonBackReference
private List<User> users = new ArrayList<User>(0);

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


@OneToMany(fetch = FetchType.LAZY, mappedBy = "userClass")
public List<User> getUsers() {
     return this.users;
}

这是依赖项：

<dependencies>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>4.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>4.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.8.2.RELEASE</version>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-aop</artifactId>
                </exclusion>
            </exclusions>
        </dependency>


        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <scope>provided</scope>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.1</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <dependency>
            <groupId>com.thoughtworks.xstream</groupId>
            <artifactId>xstream</artifactId>
            <version>1.4.8</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.6.1</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-hibernate4</artifactId>
            <version>2.6.1</version>
        </dependency>



        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.34</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.3.10.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>4.3.10.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>5.1.3.Final</version>
        </dependency>

        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-core</artifactId>
            <version>3.0.5</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-jsp</artifactId>
            <version>3.0.5</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-api</artifactId>
            <version>3.0.5</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-template</artifactId>
            <version>3.0.5</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>1.7.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.12</version>
        </dependency>

        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>18.0</version>
        </dependency>


    </dependencies>

我使用“ @JsonIgnore”，“ @ JsonIdentityInfo”和“
XmlTransient”来防止递归，但是它们都不起作用，服务器报告此错误。有人能帮我吗？

谢谢。

编辑：和堆栈跟踪：

org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Infinite recursion (StackOverflowError) (through reference chain:
sss.com.model.UserClass["users"]->org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]->
org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]->org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]... .
 nested exception is com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: 
sss.com.model.UserClass["users"]->org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]->
org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]->org.hibernate.collection.internal.PersistentBag[0]->sss.com.model.User["userClass"]->sss.com.model.UserClass["users"]... . with root cause
 java.lang.StackOverflowError
    at java.io.IOException.<init>(IOException.java:58)
    at com.fasterxml.jackson.core.JsonProcessingException.<init>(JsonProcessingException.java:25)
    at com.fasterxml.jackson.core.JsonProcessingException.<init>(JsonProcessingException.java:41)
    at com.fasterxml.jackson.databind.JsonMappingException.<init>(JsonMappingException.java:143)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:689)
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:157)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:149)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:111)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:656)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:675)
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:157)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:656)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:675)
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:157)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:149)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:111)
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:656)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:675)
...

已解决：在我的原始实体中，我有5个双向关系，但是，我被注释了一个关系。原因是tomcat没有在结果页中打印异常，并且我不检查tomcat日志文件。


问题答案：

刚放 @JsonIgnore

@JsonIgnore
@OneToMany(fetch = FetchType.LAZY, mappedBy = "userClass")
public List<User> getUsers() {
     return this.users;
}

这将忽略延迟加载对象并解决您的问题。

更新资料

  • 根据Udara Seneviratne的回答，您可以bi-directional relationship通过处理@JsonManagedReference, @JsonBackReference。