将 EJB 2.0 迁移到 EJB 3.x Web 应用程序忘记了较低层值

Question

我目前正在尝试迁移一个 EAR 项目
-旧项目-
EJB 2.0
Jboss5.0.1

-新项目-
EJB 3.0
Wildfly 13.0.0Final

它是我设法创建的会话 bean，我可以调用它。它本身的逻辑似乎有效。我遇到的问题是后续行动之一似乎忘记了它在做什么。
我看到的当前问题如下：
在 class 的 Web 应用程序中，我们正在创建另一个 class 的对象，然后我们触发其父方法。然后，此父方法调用 class 并将其自身作为参数，然后检查它是哪种类型，然后根据类型为会话 bean 加注星标。然后在这个函数中调用参数函数 performExecute() 我们调用查询并实际获得正确的结果，然后我们将结果集值添加到私有 dto 成员。然后 performExecute 就完成了。然后我们回到 Web 应用程序 class，然后我们尝试使用 get 函数访问同一个 dto 成员。这个 returns 一个空指针。我想知道我是否忘记了我的会话 bean 中的某些内容？

旧会话bean：

public class TxNotSupportedCommandServerBean implements SessionBean {
 SessionContext sessionContext;

 public void ejbCreate() throws CreateException {}

 public void ejbRemove() {
   sessionContext = null;
 }

 public void ejbActivate() {}

 public void ejbPassivate() {}

 public void setSessionContext(SessionContext sessionContext) {
  this.sessionContext = sessionContext;
 }

 public void executeCommand(TargetableCommand cmd) throws CommandException {
  try {
   cmd.performExecute();
  }
  catch (CommandException ex) {
   throw ex;
  }
 }
}

新的：

@Stateless
@Remote
@TransactionManagement(value=TransactionManagementType.CONTAINER)
@TransactionAttribute(value=REQUIRED)
public class TxNotSupportedCmdServerBean  implements TxNotSupportedCmdServerRemote{

    /**
     * Default constructor. 
     */
    public TxNotSupportedCmdServerBean() {
        // TODO Auto-generated constructor stub
    }
    
    public void executeCommand(TargetableCommand cmd) throws CommandException {
        try {
          cmd.performExecute();
        }
        catch (CommandException ex) {
          throw ex;
        }
      }

}

这两个都在 EJB.Jar
该接口在 EJBClient.jar
中实现旧界面：

public interface TxNotSupportedCommandServerLocal extends EJBLocalObject {
  public void executeCommand(TargetableCommand cmd) throws CommandException;
}

新界面：

public interface TxNotSupportedCmdServerRemote {
    public void executeCommand(TargetableCommand cmd) throws CommandException;
}

下面是下一组文件，它们也在 EJBClient.jar
TargetableCommand：

public abstract class TargetableCommand implements Command {
  private boolean constraintViolated;      
  protected RequestContext requestContext; 
  protected String dataSourceName;         


  public TargetableCommand(RequestContext requestContext, String dataSourceName) {
    this.requestContext = requestContext;
    this.dataSourceName = dataSourceName;
  }

  public TargetableCommand(RequestContext requestContext) {
    this.requestContext = requestContext;
  }

  public TargetableCommand(String dataSourceName) {
    this.dataSourceName = dataSourceName;
  }

  public TargetableCommand() {
  }

  public void setConstraintViolated(boolean constraintViolated) {
    this.constraintViolated = constraintViolated;
  }

  public boolean isConstraintViolated() {
    return constraintViolated;
  }

  public abstract void performExecute() throws CommandException;

  public void execute() throws CommandException {
    CommandTarget.executeCommand(this);
  }
}

命令：

public interface Command extends Serializable {
  public void execute() throws CommandException;
}

注释的代码是旧的会话 bean。
命令目标：

public class CommandTarget {
  public CommandTarget() {
  }

  /**
   * Exekverar ett kommando i rätt miljö, t.ex. med eller utan transaktionshantering
   * @param cmd TargetableCommand Kommandot som ska utföras
   * @throws CommandException
   */
  public static void executeCommand(TargetableCommand cmd) throws CommandException {
      Context context = null;
      try {
      ServiceLocator sl = ServiceLocator.getInstance();

//      if (cmd instanceof TxRequired) {
//        TxRequiredCommandServerLocalHome cmdSrvHome = (TxRequiredCommandServerLocalHome) sl.getEJBLocalHome("TxRequiredCommandServer");
//        TxRequiredCommandServerLocal cmdSrv = cmdSrvHome.create();
//        cmdSrv.executeCommand(cmd);
//      }
//      else if(cmd instanceof TxNotSupported) {
//        TxNotSupportedCommandServerLocalHome cmdSrvHome = (TxNotSupportedCommandServerLocalHome) sl.getEJBLocalHome("TxNotSupportedCommandServer");
//        TxNotSupportedCommandServerLocal cmdSrv = cmdSrvHome.create();
//        cmdSrv.executeCommand(cmd);
//      }
//      else {
//        throw new CommandException("Cannot instanciate command server");
//      }
//      
      System.out.println("CT: Inside commandTarget. about to diffrientate what instance");
      context = JNDILookupClass.getInitialContext();
      if (cmd instanceof TxRequired) {
                System.out.println("CT: TxRequired");
              TxRequiredCmdServerRemote cmdSrv = (TxRequiredCmdServerRemote)context.lookup(JNDILookupClass.getLookupName("TxRequiredCmdServerRemoteBean", TxRequiredCmdServerRemote.class.getName()));
              cmdSrv.executeCommand(cmd);
        }
        else if(cmd instanceof TxNotSupported) {
            System.out.println("CT: TxNotSupported");
            System.out.println("CT: cmd: " + cmd.getClass());
            TxNotSupportedCmdServerRemote cmdSrv = (TxNotSupportedCmdServerRemote)context.lookup(JNDILookupClass.getLookupName("TxNotSupportedCmdServerBean", TxNotSupportedCmdServerRemote.class.getName()));
            cmdSrv.executeCommand(cmd);
        }
        else {
          throw new CommandException("Cannot instanciate command server");
        }
    }
    catch (CommandException ex) {
      throw ex;
    }
//    catch (CreateException ex) {
//      throw new CommandException(ex);
//    }
      //new catch
    catch(NamingException ex) {
     throw new CommandException(ex);
    }
    catch (ServiceLocatorException ex) {
      throw new CommandException(ex);
    }
  }
}

呼... 好的，现在这就是 EJBClient 的重要部分。现在开始 Web.war
我只粘贴了实际运行的部分，它是 returns 一个空点

public class ActionIdentitetKonsultCommand implements Command {
    
  private static Logger logger = Logger.getLogger(ActionIdentitetKonsultCommand.class);
  
  public ActionIdentitetKonsultCommand() {
  }

  public String execute(RequestContext requestContext) throws CommandException {
    GetPersonByPersnrEJBCommand personCmd;
    logger.info("execute()");
    try {
      UserBean user = (UserBean) requestContext.getSession().getAttribute("user");
      String kstnr = requestContext.getParameter("kstnr");

      //Tilldela konsultuppgifter
      personCmd = new GetPersonByPersnrEJBCommand();
      personCmd.setPersnr(user.getPersnr());
      System.out.println("AI: Before execute DTO " + personCmd.dto);
      personCmd.execute();
      System.out.println("AI: After execute DTO " + personCmd.dto);
      logger.info("person hamtad med personnummer (EJB):");
      logger.info(personCmd.getPerson().toString());

所以 personCmd.getPerson().tostring() 是导致空指针的原因。 GetPersonByPersnrEJBCommand():

public class GetPersonByPersnrEJBCommand extends TargetableCommand implements TxNotSupported {
  public PersonDTO dto;
  private long persnr;

  public GetPersonByPersnrEJBCommand() {
  }

  public void setPersnr(long persnr) {
    this.persnr = persnr;
  }

  public PersonDTO getPerson() {
    return this.dto;
  }

  public void performExecute() throws CommandException {
    try {
      QueryPersonByPersnrCommand cmd = new QueryPersonByPersnrCommand();
     
      cmd.setPersnr(persnr);
      cmd.execute();

      if(cmd.next()){
        this.dto = new PersonDTO();
        System.out.println("GP: inside PerformExecute DTO: " + dto);
        dto.setPersnr(cmd.getPersnr());
        dto.setEfternamn(cmd.getEfternamn());
        dto.setFornamn(cmd.getFornamn());
        dto.setEpostAdress(cmd.getEpostAdress());
        dto.setKonsult((cmd.getKonsult() == 1));
        dto.setAnsvarig((cmd.getAnsvarig() == 1));
        
        System.out.println("GP: Inside Perform Execute DTO: " + dto);
      }
    }
    catch (DataAccessCommandException ex) {
        System.out.println("GetPersonByPersnrEJBCommand.performExecute misslyckades " + ex.getMessage());
      throw new CommandException(ex);
    }
  }
}

就是这样；我不明白为什么它会忘记它。当我们在最后一个 class 中执行 sysouts 时，我们看到 dto 和 cmd 中都有数据，但是一旦函数结束，我们又回到调用它的 class 中，数据为空. 我怀疑它与我的会话 bean 有关，我缺少属性或其他东西。因为此代码适用于旧 JBOSS 服务器中的旧 bean。希望有人能帮助我，其他人也能从中学习。

Answer 1

我设法解决了这个问题。由于项目的范围是让它发挥作用。这不是一个漂亮的解决方案，如果有更多时间重写，这会更好。所以继续解决方案：我们需要更改 bean、targetableCommand、CommandTarget 和 GetPersonByPersnrEJBCommand

TargetableCommand - 添加方法：

public TargetableCommand execute(TargetableCommand  cmd) throws CommandException
{    
    return CommandTarget.executeCommand(cmd);
}

CommandTarget - 我们将方法 executeCommand 更改为 return 一个 TargetableCommand，并确保在 bean 完成后我们 return 该 cmd。

public static TargetableCommand executeCommand(TargetableCommand cmd) throws CommandException {
  Context context = null;
  try {     
  context = JNDILookupClass.getInitialContext();
  if (cmd instanceof TxRequired) {
          TxRequiredCmdServerRemote cmdSrv = (TxRequiredCmdServerRemote)context.lookup(JNDILookupClass.getLookupName("TxRequiredCmdServerRemoteBean", TxRequiredCmdServerRemote.class.getName()));
         cmd = cmdSrv.executeCommand(cmd);
    }
    else if(cmd instanceof TxNotSupported) {
        TxNotSupportedCmdServerRemote cmdSrv = (TxNotSupportedCmdServerRemote)context.lookup(JNDILookupClass.getLookupName("TxNotSupportedCmdServerBean", TxNotSupportedCmdServerRemote.class.getName()));
       cmd = cmdSrv.executeCommand(cmd);
    }
    else {
      throw new CommandException("Cannot instanciate command server");
    }
}
catch (CommandException ex) {
  throw ex;
}
catch(NamingException ex) {
 throw new CommandException(ex);
}
}
return cmd;
}

bean - 将方法执行命令更改为 return Targetablecommand

public TargetableCommand executeCommand(TargetableCommand cmd) throws CommandException {
    try {
      cmd = cmd.performExecute();
    }
    catch (CommandException ex) {
      throw ex;
    }
return cmd;
  }

然后最后为了让它全部工作我不得不在 classes 中创建一个新方法来执行执行所以在 GetPersonByPersnrEJBCommand class 我创建了方法 wf13Layer( );这只是一个额外的步骤：

public void wf13Layer() throws CommandException
{
    GetPersonByPersnrEJBCommand tmp;
    try{
       tmp = (GetPersonByPersnrEJBCommand) execute(this);
       dto = tmp.getPerson();
    } catch (Exception ex) {
      throw new CommandException(ex);
    }
}

这就是我为让它发挥作用所做的工作。正如我所说，这不是一个漂亮的解决方案，但它确实有效。 IT 似乎是一种组合，一旦我们在项目之间交叉，范围就会消失。为了进一步获得它，我们需要像这样对其进行分层。我真的希望这在某些时候对某人有所帮助，因为那里有很多旧代码运行。

亲切的问候很累

将 EJB 2.0 迁移到 EJB 3.x Web 应用程序忘记了较低层值

Migrating EJB 2.0 to EJB 3.x Web app forgets lower tier value

jboss5.x

ejb-3.0

ejb-2.x

wildfly