HQL - 列出國家並獲取所有州和貨幣

Question

我想列出所有國家以獲取所有相應的州和貨幣。

ConfFacade.java

public Result<List<Country>> listCountries() { 
    try { 
     String HQL = "SELECT DISTINCT o FROM Ocountry o LEFT JOIN FETCH o.ostate, o.ocurrency"; 
     List<Country> list = em.createQuery(HQL).getResultList(); 

     return new Result(Status.SUCCESS, list); 
    } catch(Exception e) { 
     e.printStackTrace(); 
     return new Result<>(Status.ERROR, Exception.GENERAL, e.getMessage()); 
    } 
} 

ConfFacadeLocal.java

public interface ConfFacadeLocal { 
 
    
 
    public Result<List<Country>> listCountries(); 
 
    
 
}

這是JSP，我使用和它的代碼：

listCountries.jsp

<% 
 
     try { 
 
      InitialContext ctx = new InitialContext(); 
 
      ConfFacadeLocal confFacadeLocal = (ConfFacadeLocal)ctx.lookup("java:comp/env/tomin"); 
 

 
      Result<List<Country>> result = confFacadeLocal.listCountries(); 
 
      if(result.isUnsuccessful()) { 
 
       throw new Exception(result.getErrMsg()); 
 
      } 
 
      
 
      List<Country> countryList = result.getObject(); 
 
      if(countryList == null) { 
 
       throw new Exception("Error."); 
 
      } 
 
      out.print("OK"); 
 
      
 
    %> 
 
      
 
      <table border="1" align="center" style="width:50%"> 
 
      <thead> 
 
       <tr> 
 
        <th>country code</th> 
 
        <th>currency code</th> 
 
        <th>state id</th> 
 
        <th>state description</th> 
 
        
 
       </tr> 
 
      </thead> 
 
      <tbody><%    
 
      for (Ocountry country : countryList){ %> 
 
       <tr> 
 
        <td><%=country.getOccode()%></td> 
 
        <td><%=country.getOcurrency().getOcucode()%></td> 
 
        <td><%=country.getOstate().getOsid()%></td> 
 
        <td><%=country.getOstate().getOsdesc()%></td> 
 

 
       </tr><% 
 
      } 
 
     } catch (Exception e) { 
 
      e.printStackTrace(); 
 
      out.print("Error: " + e.getMessage()); 
 
     } %> 
 
     
 
       
 
     
 
      </tbody> 
 
     </table>

這裏是我的錯誤：

cannot find symbol 
 
    symbol: method getOstate() 
 
    location: variable country of type com.ejb.entities.conf.Country 
 
PWC6197: An error occurred at line: 42 in the jsp file: /country/listCountries.jsp 
 
PWC6199: Generated servlet error: 
 
cannot find symbol 
 
    symbol: method getOstate() 
 
    location: variable country of type com.ejb.entities.conf.Country 
 
\t at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:129) 
 
\t at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:299) 
 
\t at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:392) 
 
\t at org.apache.jasper.compiler.Compiler.compile(Compiler.java:453) 
 
\t at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:625) 
 
\t at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375) 
 
\t at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:473) 
 
\t at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:377) 
 
\t at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) 
 
\t at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682) 
 
\t at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318) 
 
\t at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160) 
 
\t at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734) 
 
\t at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673) 
 
\t at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99) 
 
\t at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174) 
 
\t at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415) 
 
\t at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282) 
 
\t at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459) 
 
\t at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167) 
 
\t at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201) 
 
\t at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175) 
 
\t at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235) 
 
\t at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119) 
 
\t at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284) 
 
\t at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201) 
 
\t at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133) 
 
\t at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112) 
 
\t at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77) 
 
\t at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561) 
 
\t at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112) 
 
\t at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117) 
 
\t at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56) 
 
\t at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137) 
 
\t at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565) 
 
\t at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545) 
 
\t at java.lang.Thread.run(Thread.java:745)

誰能幫助解決？

Answer 1

從您的JSP錯誤日誌中，我猜你錯過了將#listCountries方法聲明到ConfFacadeLocal的bean接口。

添加所需的方法聲明的接口應該解決的問題：

public interface ConfFacadeLocal { 

    // other API methods ... 

    public Result<List<Country>> listCountries(); 

} 

Answer 2

有（41行）：

<td><%=currency.getOcucode()%></td> 

您使用的是貨幣變量，它並沒有被宣佈。

看來，貨幣是在你程序中的「國家」類的屬性，所以也許你應該寫，而不是

<td><%=country.getCurrency().getOcucode()%></td> 

您有「國家」變量同樣的問題。