奇怪的實體管理器錯誤

Question

我做了這個查詢：

Usuario user1=(Usuario) request.getSession().getAttribute("user");
String query1 = "SELECT f FROM Favorito f WHERE f.usuarioBean = 'user1'";

我在這里調用 Manager 方法

List<Favorito> favoritos = managerFavorito.getFavoritoByUser(query1);

Manager 方法如下所示：

public List<Favorito> getFavoritoByUser(String query1) {
        EntityManager em = getEntityManager();
        List<Favorito> results = null;
        try {
            Query query = em.createNativeQuery(query1);
            results = (List<Favorito>) query.getResultList();
        } finally {
            em.close();
        }
        return results;
    }

錯誤：

 org.apache.openjpa.persistence.ArgumentException: Metadata not found for type "class java.lang.String". Class not improved.

完整錯誤：

[25/11/12 0:17:37:538 CET] 0000002b servlet       E com.ibm.ws.webcontainer.servlet.ServletWrapper service SRVE0068E: Se ha creado una excepción no detectada en uno de los métodos de servicio del servlet servletControl en la aplicación MotorSalesGR83.15. Excepción creada: <openjpa-2.0.2-SNAPSHOT-r422266:1032678 nonfatal user error> org.apache.openjpa.persistence.ArgumentException: No se han encontrado metadatos para el tipo "class java.lang.String". La clase no se ha mejorado.
    at org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:377)
    at org.apache.openjpa.meta.MetaDataRepository.getMetaData(MetaDataRepository.java:358)
    at org.apache.openjpa.jdbc.meta.MappingRepository.getMapping(MappingRepository.java:355)
    at org.apache.openjpa.jdbc.meta.strats.RelationStrategies.toDataStoreValue(RelationStrategies.java:88)
    at org.apache.openjpa.jdbc.meta.strats.RelationFieldStrategy.toDataStoreValue(RelationFieldStrategy.java:836)
    at org.apache.openjpa.jdbc.meta.FieldMapping.toDataStoreValue(FieldMapping.java:938)
    at org.apache.openjpa.jdbc.kernel.exps.PCPath.toDataStoreValue(PCPath.java:844)
    at org.apache.openjpa.jdbc.kernel.exps.Lit.calculateValue(Lit.java:109)
    at org.apache.openjpa.jdbc.kernel.exps.CompareEqualExpression.appendTo(CompareEqualExpression.java:98)
    at org.apache.openjpa.jdbc.kernel.exps.SelectConstructor.buildWhere(SelectConstructor.java:298)
    at org.apache.openjpa.jdbc.kernel.exps.SelectConstructor.evaluate(SelectConstructor.java:93)
    at org.apache.openjpa.jdbc.kernel.JDBCStoreQuery.createWhereSelects(JDBCStoreQuery.java:349)
    at org.apache.openjpa.jdbc.kernel.JDBCStoreQuery.executeQuery(JDBCStoreQuery.java:187)
    at org.apache.openjpa.kernel.ExpressionStoreQuery$DataStoreExecutor.executeQuery(ExpressionStoreQuery.java:776)
    at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:1003)
    at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:861)
    at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:792)
    at org.apache.openjpa.kernel.DelegatingQuery.execute(DelegatingQuery.java:542)
    at org.apache.openjpa.persistence.QueryImpl.execute(QueryImpl.java:288)
    at org.apache.openjpa.persistence.QueryImpl.getResultList(QueryImpl.java:302)
    at entities.controller.FavoritoManager.getVehiculoFavorito(FavoritoManager.java:172)
    at tiw.servletControl.doPost(servletControl.java:78)
    at tiw.servletControl.doGet(servletControl.java:38)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:718)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3933)
    at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:276)
    at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:931)
    at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1583)
    at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:186)
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452)
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511)
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305)
    at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:83)
    at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
    at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
    at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
    at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
    at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
    at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775)
    at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
    at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1604)

有問題？ 我開始認為我無法使用簡單的 Where 在 Favorito 中搜索行。

Answer 1

您的代碼中發生了一些奇怪的事情。

首先，您將user1對象從會話中拉出，但從不使用它。 此外，在您的查詢中，您斷言f.usuarioBean等於字符串“user1”，我想這永遠不會是真的：

String query1 = "SELECT f FROM Favorito f WHERE f.usuarioBean = 'user1'";

我想你的意思是做這樣的事情：

String query1 = "SELECT f FROM Favorito f WHERE f.usuarioBean = '" + user1.getId() + "'";

一個更好的方法（真的，唯一正確的方法）是使用查詢參數：

String query1 = "SELECT f FROM Favorito f WHERE f.usuarioBean = ?";
// and then later:
query.setParameter(1, user1);

其次，您正在調用createNativeQuery ，它將 SQL 查詢字符串作為參數。 但是，您傳遞的字符串不是 SQL，而是 JPQL（您不能在 SQL 中選擇表別名，是嗎？）。 您應該調用createQuery ，或者更好的是，重載createQuery(String, Class) ，它創建一個TypedQuery ，以獲得更好的類型安全性。