Unable to locate appropriate constructor on class

最新推荐文章于 2021-08-10 17:32:16 发布

风之雪舞

最新推荐文章于 2021-08-10 17:32:16 发布

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分类专栏： S2SH 文章标签： Hibernate Spring

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这篇博客探讨了一个在使用Hibernate和Spring时遇到的问题，即'Unable to locate appropriate constructor on class'错误。问题源于Oracle SQL查询中count函数返回的Long类型与预期的int不匹配。解决方法是将聚合函数返回的字段类型转换为int。

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org.hibernate.hql.internal.ast.QuerySyntaxException: Unable to locate appropriate constructor on class [com.skyblogs.entity.Type] [select new com.skyblogs.entity.Type(t.typeId, t.detail, count(t.titleName) as count, t.titleName) from com.skyblogs.entity.Blogs b ,com.skyblogs.entity.Type t where t.isHost = 1 and t.typeId = b.type.typeId and to_char(b.writeTime,'yyyy-mm-dd') > to_char(sysdate-?,'yyyy-mm-dd') and rownum <= ? group by t.typeId,t.detail, t.titleName]
at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54)
at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:47)
at org.hibernate.hql.internal.ast.ErrorCounter.throwQueryException(ErrorCounter.java:79)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:255)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:105)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:168)
at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:221)
at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:199)
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1778)
at com.skyblogs.util.HibernateUtil.queryByHQL(HibernateUtil.java:156)
at com.skyblogs.dao.impl.AbsBaseDao.queryByHQL(AbsBaseDao.java:37)
at com.skyblogs.biz.impl.BlogsBizImpl.querySubject(BlogsBizImpl.java:202)
at com.skyblogs.test.TestBizImpl.testQuerySubject(TestBizImpl.java:313)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

这是我的构造方法
public Type(){
}

public Type(int typeId, String detail, int count, String titleName) {
this.typeId = typeId;
this.detail = detail;
this.count = count;
this.titleName = titleName;
}

之所以出现这个错误，是因为用oracle聚合函数count查询，返回的字段类型为Long，所以必须将该聚合函数返回字段类型转换int就可以了