java - tutorial - excepción en la aplicación GWT RPC

gwt json

Question

Estoy usando GWT RPC e Hibernate para insertar y recuperar datos de MySQL usando eclipse. He escrito dos métodos en las interfaces de servicio para insertar y recuperar datos de una sola tabla de MySQL.

El programa funciona bien, pero está planteando esta excepción.

Exception in thread "UnitCacheLoader" java.lang.RuntimeException: Unable to read from byte cache
    at com.google.gwt.dev.util.DiskCache.transferFromStream(DiskCache.java:166)
    at com.google.gwt.dev.util.DiskCacheToken.readObject(DiskCacheToken.java:87)
    at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeReadObject(Unknown Source)
    at java.io.ObjectInputStream.readSerialData(Unknown Source)
    at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.defaultReadFields(Unknown Source)
    at java.io.ObjectInputStream.readSerialData(Unknown Source)
    at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)
    at com.google.gwt.dev.javac.PersistentUnitCache.loadUnitMap(PersistentUnitCache.java:493)
    at com.google.gwt.dev.javac.PersistentUnitCache.access$000(PersistentUnitCache.java:92)
    at com.google.gwt.dev.javac.PersistentUnitCache$UnitCacheMapLoader.run(PersistentUnitCache.java:122)
Caused by: java.io.StreamCorruptedException: unexpected EOF in middle of data block
    at java.io.ObjectInputStream$BlockDataInputStream.refill(Unknown Source)
    at java.io.ObjectInputStream$BlockDataInputStream.read(Unknown Source)
    at java.io.ObjectInputStream.read(Unknown Source)
    at java.io.InputStream.read(Unknown Source)
    at com.google.gwt.dev.util.DiskCache.transferFromStream(DiskCache.java:154)
    ... 16 more

Clase ServiceImpl:

package rpctest.server;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.google.gwt.user.server.rpc.RemoteServiceServlet;
//import com.hib.HibernateUtil;

import org.hibernate.Session;
import org.hibernate.Transaction;
import rpctest.shared.User;
import rpctest.client.RpctestService;

public class RpctestServiceImpl extends RemoteServiceServlet  implements RpctestService {

        public String addUser(String name1, String name2)
            throws IllegalArgumentException {

              Transaction trns = null;
              Session session = HibernateUtil.getSessionFactory().openSession();
              try {
               trns = session.beginTransaction();

               User user = new User();

               user.setFirstName(name1);
               user.setLastName(name2);

               session.save(user);

               session.getTransaction().commit();
              } catch (RuntimeException e) {
               if(trns != null){
                trns.rollback();
               }
               e.printStackTrace();
              } finally{
               session.flush();
               session.close();
              }

        return name1+name2; // to test flextable entris only 
    }

    @Override
    public  User[] getUser()
             {

              List<User> getUser = null;

              Transaction trns = null;
              Session session = HibernateUtil.getSessionFactory().openSession();
              try {
               trns = session.beginTransaction();
               getUser = session.createQuery("from User").list();

               //* for (Iterator<User> iter = getUser.iterator(); iter.hasNext();) 
              //{
                //User user = iter.next();
                //
              //*}             

               trns.commit();
              } catch (RuntimeException e) {
               if(trns != null){
                trns.rollback();
               }
               e.printStackTrace();
              } finally{
               session.flush();
               session.close();
             }
              return getUser.toArray(new User[getUser.size()]);
        }
}

clase de entrada:

package rpctest.client;

import java.util.ArrayList;

import rpctest.shared.User;
import rpctest.shared.FieldVerifier;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyUpEvent;
import com.google.gwt.event.dom.client.KeyUpHandler;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;

import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyPressHandler;

/**
 * Entry point classes define <code>onModuleLoad()</code>.
 */
public class Rpctest implements EntryPoint {

    final TextBox firstName = new TextBox();
    final TextBox lastName = new TextBox();
    final Button ans = new Button("Add User");
    //final Label label1 = new Label("First Name");
    //final Label label2 = new Label("Last Name");
    private FlexTable userFlexTable = new FlexTable();
    //final Label errorLabel = new Label();

    private VerticalPanel mainpanel = new VerticalPanel();
    private HorizontalPanel addpanel1 = new HorizontalPanel();
    private HorizontalPanel addpanel2 = new HorizontalPanel();
    private final RpctestServiceAsync calNumbers = GWT
            .create(RpctestService.class);

    /**
     * This is the entry point method.
     */
    public void onModuleLoad() {

        userFlexTable.setText(0, 0, "User ID");
        userFlexTable.setText(0, 1, "First Name");
        userFlexTable.setText(0, 2, "Second Name");
        userFlexTable.setText(0, 3, "Remove");

        //add input boxes to panel
        addpanel1.add(firstName);
        addpanel1.add(lastName);

        firstName.setFocus(true);

        //add input 
        mainpanel.add(userFlexTable);
        mainpanel.add(addpanel1);
        addpanel1.add(ans);

        ans.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                        addStock();                 
            }
        });

        lastName.addKeyPressHandler(new KeyPressHandler() {
              public void onKeyPress(KeyPressEvent event) {
                  if (event.getCharCode() == KeyCodes.KEY_ENTER) {
                      addStock();
                  }
                }
              });

        RootPanel.get().add(mainpanel);
        getUser();
    }

private void addStock(){

        String name1 = firstName.getValue();
        // Stock code must be between 1 and 10 chars that are numbers, letters, or dots.
        /*if (!name1.matches("^[0-9A-Z//.]{1,10}$")) {
          Window.alert("''" + name1 + "'' is not a valid name.");
          firstName.selectAll();
          return;
        }*/
         firstName.setValue("");

        String name2 = lastName.getValue();
        /*if (!name2.matches("^[0-9A-Z//.]{1,10}$")) {
              Window.alert("''" + name1 + "'' is not a valid name.");
              lastName.selectAll();
              return;
            }*/
        lastName.setValue("");
        firstName.setFocus(true);

        calNumbers.addUser(name1,name2,
            new AsyncCallback<String>() {
            public void onFailure(Throwable caught) {
                // Show the RPC error message to the user
                    Window.alert("check your inputs");
                }

            @Override
            public void onSuccess(String result) {
            // TODO Auto-generated method stub
                // Add the user to the table.
              //  int row = userFlexTable.getRowCount();
              //  userFlexTable.setText(row, 1, result);

                getUser();
            }
        });
    }

private void getUser(){

       calNumbers.getUser(new AsyncCallback<User[]>() {
            public void onFailure(Throwable caught) {
                // Show the RPC error message to the user
                    Window.alert("Problem in database connection");
                }

            @Override
            public void onSuccess(User[] result) {
                // TODO Auto-generated method stub
                for(int i = 0; i < result.length; i ++)
                    {
                     //String s = result[i].getFirstName();               
                     int row = userFlexTable.getRowCount();
                     userFlexTable.setText(row, 0, result[i].getId().toString());
                     userFlexTable.setText(row, 1, result[i].getFirstName());
                     userFlexTable.setText(row, 2, result[i].getLastName());
                        }



            }
        });

      }
}

Answer 1

¿Quiere decir que su código funciona bien pero ve esta excepción en los registros? La excepción básicamente significa que la caché de compilación no se pudo cargar por algún motivo. Lo más probable es que el caché se haya corrompido por algún motivo, así que intente eliminar la carpeta gwt-UnitCache de su proyecto, esto debería ayudar.

Answer 2

Tal vez fue un mensaje de error y usted hizo clic en Sí: