查询时Hibernate抛出StackOverflowError

Question

我有两个实体定义如下：

@Entity
@Table(name = "shapes")
public class Shape {
    @Id
    private int id;

    @Column(nullable = false)
    private String name;

    @OneToMany(mappedBy="shape", fetch = FetchType.EAGER)
    private List<ShapeElement> shapeElements;

    public int getId() {
        return id;
    }
}

和

@Entity
@IdClass(ShapeElementPK.class)
@Table(name = "shape_elements")
public class ShapeElement {
    @Id
    @ManyToOne
    @JoinColumn(name = "shape_id")
    private Shape shape;

    @Id
    @Column(name = "x_delta")
    private int xDelta;

    @Id
    @Column(name = "y_delta")
    private int yDelta;
}

使用以下IdClass：

@Embeddable
public class ShapeElementPK implements Serializable {
    private static final long serialVersionUID = 284329766961384662L;

    private Shape shape;
    private int xDelta;
    private int yDelta;

    @Override
    public boolean equals(Object otherObject) {
        if (! (otherObject instanceof ShapeElementPK)) {
            return false;
        }

        ShapeElementPK otherPK = (ShapeElementPK) otherObject;
        return otherPK.shape.getId() == shape.getId() &&
                otherPK.xDelta == xDelta &&
                otherPK.yDelta == yDelta;
    }

    @Override
    public int hashCode() {
        int hash = 5;
        hash = 11 * hash + Objects.hashCode(this.shape);
        hash = 11 * hash + this.xDelta;
        hash = 11 * hash + this.yDelta;
        return hash;
    }
}

现在我跑

List<Shape> allShapes = session.createCriteria(Shape.class).list();

我最后得到一个带有以下反向跟踪的StackOverflowError：

Caused by: java.lang.StackOverflowError
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.mysql.jdbc.StatementImpl.getWarnings(StatementImpl.java:2556)
    at com.zaxxer.hikari.proxy.PreparedStatementJavassistProxy.getWarnings(PreparedStatementJavassistProxy.java)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.handleAndClearWarnings(SqlExceptionHelper.java:320)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.logAndClearWarnings(SqlExceptionHelper.java:273)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.close(JdbcCoordinatorImpl.java:529)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.release(JdbcCoordinatorImpl.java:421)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:160)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:186)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.mysql.jdbc.StatementImpl.getWarnings(StatementImpl.java:2556)
    at com.zaxxer.hikari.proxy.PreparedStatementJavassistProxy.getWarnings(PreparedStatementJavassistProxy.java)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.handleAndClearWarnings(SqlExceptionHelper.java:320)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.logAndClearWarnings(SqlExceptionHelper.java:273)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.close(JdbcCoordinatorImpl.java:529)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.release(JdbcCoordinatorImpl.java:421)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:160)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:186)
    at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:4126)
    at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:503)
    at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:468)
    at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:213)
    at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:275)
    at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:151)
    at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1070)
    at org.hibernate.internal.SessionImpl.internalLoad(SessionImpl.java:989)
    at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:716)
    at org.hibernate.type.EntityType.resolve(EntityType.java:502)
    at org.hibernate.type.ComponentType.resolve(ComponentType.java:666)
    at org.hibernate.loader.plan.exec.process.internal.EntityReferenceInitializerImpl.resolveEntityKey(EntityReferenceInitializerImpl.java:158)
    at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.resolveEntityKey(AbstractRowReader.java:148)
    at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.readRow(AbstractRowReader.java:97)
    at org.hibernate.loader.plan.exec.internal.EntityLoadQueryDetails$EntityLoaderRowReader.readRow(EntityLoadQueryDetails.java:255)
    at org.hibernate.loader.plan.exec.process.internal.ResultSetProcessorImpl.extractResults(ResultSetProcessorImpl.java:129)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:138)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:186)
    at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:4126)
    at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:503)
    at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:468)
    at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:213)
    at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:275)
    at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:151)
    at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1070)
    at org.hibernate.internal.SessionImpl.internalLoad(SessionImpl.java:989)
    at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:716)
    at org.hibernate.type.EntityType.resolve(EntityType.java:502)
    at org.hibernate.type.ComponentType.resolve(ComponentType.java:666)
    .... etc ... it keeps repeating like this ...

我做错了什么？这是使用Hibernate 4.3.6.Final。

修改

我将ShapeElementPK更改为以下内容，似乎解决了这个问题：

@Embeddable
public class ShapeElementPK implements Serializable {
    private static final long serialVersionUID = 284329766961384662L;

    private int shape;
    private int xDelta;
    private int yDelta;

    @Override
    public boolean equals(Object otherObject) {
        if (! (otherObject instanceof ShapeElementPK)) {
            return false;
        }

        ShapeElementPK otherPK = (ShapeElementPK) otherObject;
        return otherPK.shape == shape &&
                otherPK.xDelta == xDelta &&
                otherPK.yDelta == yDelta;
    }

    @Override
    public int hashCode() {
        int hash = 5;
        hash = 11 * hash + this.shape;
        hash = 11 * hash + this.xDelta;
        hash = 11 * hash + this.yDelta;
        return hash;
    }
}

更改是将形状定义为int而不是ShapeElementPK中的Shape。

Answer 1

这可能是由于模型之间存在循环关系。是否可以在ShapeElementPK中使用shape_id而不是整个Shape对象？