SDN4：ClassCastException：無法將java.util.HashMap強制轉換為[EntityNode]

Question

更新到SDN4后，我們的代碼出現了一個問題：

 java.lang.ClassCastException: java.util.HashMap cannot be cast to com.example.server.model.neo4j.node.Item
    at  com.example.server.service.relationship.friend.FriendRelationshipService.getSkillUuidByPotentialSkillName (FriendRelationshipService.java:257)
    at com.example.server.service.relationship.friend.FriendRelationshipService.createFriendRequestRelationshipBetweenPeople(FriendRelationshipService.java:211)
    at com.example.server.service.relationship.friend.FriendRelationshipService.sendFriendRequestHelper(FriendRelationshipService.java:171)
    at com.example.server.service.relationship.friend.FriendRelationshipService.sendFriendRequest(FriendRelationshipService.java:81)
    at com.example.server.test.integration.controller.api.friends.TestLoadFriendRequestsBothWays.testLoadFriendRequestsBothWaysNullCommonSkillNameSupplied(TestLoadFriendRequestsBothWays.java:184)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:85)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:86)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:243)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:182)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

導致異常的代碼如下：

 Iterable<Item> items = itemRepository.findItemsByPerson(person.getUuid(), new Pagination(0, 1));
 for(Item item : items) { // Stacktrace leads the issue to here.
    currItem = item; 
    break;
 }

也許這與for-each循環有關，因為代碼的其他部分似乎也是如此，這也顯示了此問題。

更新05/08/2015 ：Item類如下：

@NodeEntity
public class Item extends Entity implements Packageable {

    private String name; 

    private String shortDescription;

    private boolean isUserCreatedItem = false; 

    private double timestamp;

    @Relationship(type = "CREATED_BY")
    private Person creator;

    public Item() {

    }

    /**
     * This should be called after instantiating a new node (indicating a new node is to be added to the database)
     */
    @Override
    public void init() {
        super.init();
    }

// Other methods here

}

和Entity類：

public abstract class Entity {

    private String uuid;    
    @GraphId private Long id;

    public void init() {
        // generate the UUID
        if(uuid == null) {
            uuid = Util.generateUUID();
        }
    }
}

存儲庫查詢方法：

@Query("MATCH (item)<-[:HAS_ITEM]-(you {uuid: {0}}) "
        + "RETURN DISTINCT item "
        + "ORDER BY item.name")
Iterable<Item> findItemsByPerson(String personUuid);

任何幫助將非常感激。

干杯

Answer 1

您可以在https://jira.spring.io/browse/DATAGRAPH-727上跟蹤此錯誤。

作為臨時的解決方法，請使用Collection而不是Iterable 。