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我最近正在使用 mongoDB 数据库进行 JAVA 项目。所以我决定使用eclipselink 2.4。关于查询，它允许通常的“类似 SQL”的查询，但也（据说）允许本机 mongoDB 查询。我按照本教程进行操作，一切正常。我能够运行 findOne() 本机 mongoDB 查询 (queryOne) 但我无法运行 find() 查询（queryAll 不起作用）...

  1. 查询 queryOne = em.createNativeQuery("db.ORDER.findOne()", Order.class);

  2. 查询 queryAll = em.createNativeQuery("db.ORDER.find()", Order.class);

执行查询时出现错误：

Exception in thread "main" Local Exception Stack: 
Exception [EclipseLink-6044] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.QueryException
Exception Description: The primary key read from the row [EISMappedRecord(
    value => DBQuery: myTest.ORDER -> undefined)] during the execution of the query was detected to be null.  Primary keys must not contain null.
Query: ReadAllQuery(referenceClass=Order )
    at org.eclipse.persistence.exceptions.QueryException.nullPrimaryKeyInBuildingObject(QueryException.java:912)
    at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:586)
    at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:562)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:776)
    at org.eclipse.persistence.queries.ReadAllQuery.registerResultInUnitOfWork(ReadAllQuery.java:781)
    at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:433)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1149)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:852)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1108)
    at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:392)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1196)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2875)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1602)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1584)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1549)
    at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:231)
    at org.eclipse.persistence.internal.jpa.QueryImpl.getResultList(QueryImpl.java:411)
    at example.Test.testQuery(Test.java:171)
    at example.Test.main(Test.java:54)

使用 MongoDB shell 执行查询：

{ "_id" : "5061DC17E4B0881F592675A5", "TOTALCOST" : 3187, "SHIPPINGADDRESS" : [     {   "POSTALCODE" : "L5J1H7",    "COUNTRY" : "Canada",   "PROVINCE" : "ON",  "CITY" : "Ottawa",  "STREET" : "17 Jane St." } ], "ORDERLINES" : [  {   "DESCRIPTION" : "machine",  "COST" : 2999,  "LINENUMBER" : 1 },     {   "DESCRIPTION" : "shipping",     "COST" : 129,   "LINENUMBER" : 2 },     {   "DESCRIPTION" : "installation",     "COST" : 59,    "LINENUMBER" : 3 } ], "VERSION" : NumberLong(1), "DESCRIPTION" : "Pinball machine", "CUSTOMER__id" : "5061DC17E4B0881F592675A4", "BILLINGADDRESS" : [   {   "POSTALCODE" : "L5J1H7",    "COUNTRY" : "Canada",   "PROVINCE" : "ON",  "CITY" : "Ottawa",  "STREET" : "17 Jane St." } ] }
{ "_id" : "5061DC17E4B0881F592675A6", "TOTALCOST" : 565, "SHIPPINGADDRESS" : [  {   "POSTALCODE" : "L5J1H7",    "COUNTRY" : "Canada",   "PROVINCE" : "ON",  "CITY" : "Ottawa",  "STREET" : "17 Jane St." } ], "ORDERLINES" : [  {   "DESCRIPTION" : "machine",  "COST" : 500,   "LINENUMBER" : 1 },     {   "DESCRIPTION" : "balls",    "COST" : 5,     "LINENUMBER" : 2 },     {   "DESCRIPTION" : "shipping",     "COST" : 60,    "LINENUMBER" : 3 } ], "VERSION" : NumberLong(1), "DESCRIPTION" : "Foosball", "CUSTOMER__id" : "5061DC17E4B0881F592675A4", "BILLINGADDRESS" : [  {   "POSTALCODE" : "L5J1H8",    "COUNTRY" : "Canada",   "PROVINCE" : "ON",  "CITY" : "Ottawa",  "STREET" : "7 Bank St." } ] }
{ "_id" : "5061DC17E4B0881F592675A8", "TOTALCOST" : 402, "SHIPPINGADDRESS" : [  {   "POSTALCODE" : "L5J1H7",    "COUNTRY" : "Canada",   "PROVINCE" : "ON",  "CITY" : "Ottawa",  "STREET" : "17 Jane St." } ], "ORDERLINES" : [  {   "DESCRIPTION" : "table",    "COST" : 300,   "LINENUMBER" : 1 },     {   "DESCRIPTION" : "balls",    "COST" : 5,     "LINENUMBER" : 2 },     {   "DESCRIPTION" : "rackets",  "COST" : 15,    "LINENUMBER" : 3 },     {   "DESCRIPTION" : "net",  "COST" : 2,     "LINENUMBER" : 4 },     {   "DESCRIPTION" : "shipping",     "COST" : 80,    "LINENUMBER" : 5 } ], "VERSION" : NumberLong(1), "DESCRIPTION" : "Pingpong table", "CUSTOMER__id" : "5061DC17E4B0881F592675A7", "BILLINGADDRESS" : [    {   "POSTALCODE" : "L5J1H8",    "COUNTRY" : "Canada", "PROVINCE" : "ON",    "CITY" : "Ottawa",  "STREET" : "7 Bank St." } ] }

如果您能告诉我如何解决此问题或一些解决方法，我将不胜感激。

编辑：JPQL 查询可能很有用，我正在使用一些作为解决方法，但是，我目前无法查询参考 ID。例如，如果我有一个带有客户参考的订单（订单只保存客户的 id）和 mongoDB 查询，我会像这样搜索：

db.ORDER.find({"CUSTOMER__id": "ID"})

JPQL 类似的查询我相信会是这样的：

query = em.createQuery("Select o from Order o where o.customer.id = \"ID\"");

然而，再一次......不工作！错误：

Exception in thread "main" Local Exception Stack: 
Exception [EclipseLink-6168] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.QueryException
Exception Description: Query failed to prepare, unexpected error occurred: [java.lang.ClassCastException: org.eclipse.persistence.eis.mappings.EISOneToOneMapping cannot be cast to org.eclipse.persistence.mappings.OneToOneMapping].
Internal Exception: java.lang.ClassCastException: org.eclipse.persistence.eis.mappings.EISOneToOneMapping cannot be cast to org.eclipse.persistence.mappings.OneToOneMapping
Query: ReadAllQuery(referenceClass=Order jpql="Select o from Order o where o.customer.id = "ID"")
    at org.eclipse.persistence.exceptions.QueryException.prepareFailed(QueryException.java:1572)
    at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:633)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.checkPrepare(ObjectLevelReadQuery.java:882)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:838)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1108)
    at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:392)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1196)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2875)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1602)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1584)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1549)
    at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:231)
    at org.eclipse.persistence.internal.jpa.QueryImpl.getResultList(QueryImpl.java:411)
    at example.Test.testQuery(Test.java:175)
    at example.Test.main(Test.java:55)
Caused by: java.lang.ClassCastException: org.eclipse.persistence.eis.mappings.EISOneToOneMapping cannot be cast to org.eclipse.persistence.mappings.OneToOneMapping
    at org.eclipse.persistence.internal.expressions.RelationExpression.checkForeignKeyJoinOptimization(RelationExpression.java:512)
    at org.eclipse.persistence.internal.expressions.RelationExpression.normalize(RelationExpression.java:535)
    at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalize(SQLSelectStatement.java:1365)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.buildNormalSelectStatement(ExpressionQueryMechanism.java:543)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.prepareSelectAllRows(ExpressionQueryMechanism.java:1675)
    at org.eclipse.persistence.queries.ReadAllQuery.prepareSelectAllRows(ReadAllQuery.java:719)
    at org.eclipse.persistence.queries.ReadAllQuery.prepare(ReadAllQuery.java:656)
    at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:614)
    ... 13 more

谢谢

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2 回答 2

0

我不认为 find() 通过本机 MongoDB API 与 findOne() 工作相同。

当您在没有类的情况下执行本机查询时会发生什么？

即查询queryAll = em.createNativeQuery("db.ORDER.find()"); queryAll.getResultList();

你拿什么回来？

我不认为直接支持本机 find() （但您可以将 JPQL 用于大多数查询）。请为此记录一个错误，应该有一些方法可以让它工作。

于 2012-09-26T13:23:11.353 回答
0

它似乎试图获取一个主键为空的对象。此外，如果按顺序创建记录，A5, A6 and A8.看起来 A7 会混乱吗？

是否可以删除 ORDER 文档并再次运行测试（插入和获取）？

于 2012-09-25T16:48:10.333 回答