在Java中的ResultSet上调用next时出现异常

时间:2013-04-06 19:10:16

标签: java database resultset

我正在使用数据库,我正在从中选择一些东西,就像我做了一千次。但是这一次,程序只是在调用resultSet.next()时冻结,并在一段时间后抛出时间异常。任何想法,我哪里可能有错?这是我的代码:

 try {
        connection = dataSource.getConnection();
        connection.setAutoCommit(false);
        query = connection.prepareStatement(
                "SELECT * FROM INGREDIENTS WHERE RECIPEID = ?");

        query.setLong(1, recipe.getId());

        ResultSet resultsDB = query.executeQuery();

        SortedSet<Ingredient> result = new TreeSet<Ingredient>();
        while (resultsDB.next()) {
            Ingredient output = rowToIngredient(resultsDB);
            validate(output);

            result.add(output);
        }
        connection.commit();
        return result;
     }

当程序在while循环中被调用为条件时,程序会在resultsDB.next()处完全冻结。当第一次执行这部分代码时,它可以工作,当程序第二次到达另一个数据时,.next()方法冻结程序。程序永远不会进入循环,我使用了断点,并且在条件被评估的行上失败。感谢您的建议

这整个代码是循环的,可以吗?就我使用数据源而言,它应该是

错误:

java.sql.SQLTransactionRollbackException: A lock could not be obtained within the time requested
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.closeOnTransactionError(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.movePosition(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.next(Unknown Source)
    at org.apache.commons.dbcp.DelegatingResultSet.next(DelegatingResultSet.java:207)
    at org.apache.commons.dbcp.DelegatingResultSet.next(DelegatingResultSet.java:207)
    at fi.muni.pv168.RecipebookImpl.getIngredientsOfRecipe(RecipebookImpl.java:53)
    at fi.muni.pv168.RecipebookImpl.isIngredientInRecipe(RecipebookImpl.java:324)
    at fi.muni.pv168.RecipebookImpl.addIngredientsToRecipe(RecipebookImpl.java:92)
    at fi.muni.pv168.RecipebookImplTest.testFindRecipesByIngredients(RecipebookImplTest.java:390)
    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:601)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:53)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:123)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:104)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:164)
    at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:110)
    at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:175)
    at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcessWhenForked(SurefireStarter.java:107)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:68)
Caused by: java.sql.SQLException: A lock could not be obtained within the time requested
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
... 46 more

还有更多

1 个答案:

答案 0 :(得分:1)

您必须有另一个并发的非提交事务,该事务正在更新您尝试读取的行。这会导致行被锁定,并且您的事务要等到释放此锁定。

如果您使用工具在数据库上执行请求,请确保在此工具中提交或回滚当前事务。如果您有另一个应用程序或同一应用程序中使用同一数据库的另一个线程,请检查它是否没有长时间运行的事务。