java - JPA 2.0，如何修复以下2个错误

Question

我实际上正在学习 JPA2.0，但我遇到了以下错误，考虑一下我使用 eclipse 作为 IDE。

Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1215)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1148)
    at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:307)
    at com.banking.core.persistence.utils.EntityManagerTest.main(EntityManagerTest.java:38)
Caused by: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.loader.Loader.doList(Loader.java:2536)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276)
    at org.hibernate.loader.Loader.list(Loader.java:2271)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:452)
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1268)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:274)
    ... 1 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'loanaccoun0_.id' in 'field list'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3597)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3529)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1990)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2151)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2625)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2119)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2281)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1953)
    at org.hibernate.loader.Loader.doQuery(Loader.java:802)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
    at org.hibernate.loader.Loader.doList(Loader.java:2533)
    ... 9 more

这是我现在正在使用的查询...

LoanAccount.class

@Entity
@Table(schema="BANKING_CORE", name="NUMBER_OF_PAYMENTS")
@DiscriminatorValue("LA")
@NamedQuery(name = "LoanAccount.findByNumberofPayments", query = "SELECT lc from LoanAccount lc WHERE lc.numberOfPayments = :number_of_payments")

这是查询本身

entitymanger.class

LoanAccount lc = (LoanAccount)  em.createNamedQuery("LoanAccount.findByNumberofPayments").setParameter("number_of_payments", 25).getSingleResult();
System.out.println(lc.getNumberOfPayments()+" "+lc.getCutOffDate());

Answer 1

首先，似乎您更新了实体，但表尚未重新创建。确保您的 hibernate 配置中的设置 hbm2dll.auto 是 update 或 create-drop

最后将查询更改为FROM LoanAccount WHERE numberOfPayment = :number_of_ payments

同时在 hibernate 配置中激活 show_sql 并查看生成的 sql 是什么。