GWT简单RPC用例问题：包含代码

Question

我正在尝试研究如何使用GWT RPC将域对象从服务器端发送到客户端。我编写了一个非常简单的用例，它代表了我（以及其他人）需要做的事情但目前无法开始工作。

我已经搜索了文档，教程和论坛，但他们要么显示字符串被传递，要么提供解释（当我将它应用于此时）仍然无效。

希望有人可以向我和其他人解释为什么这段代码不起作用以及如何让它工作。

谢谢。

以下是错误消息。

13:12:54.328 [DEBUG] [org.redboffin.worldhug.Test] Validating newly compiled units
13:12:54.328 [ERROR] [org.redboffin.worldhug.Test] Errors in 'file:/C:/Documents%20and%20Settings/Darren/workspace/WorldHug/src/org/redboffin/worldhug/client/test/TestService.java'
13:12:54.343 [ERROR] [org.redboffin.worldhug.Test] Line 14: No source code is available for type org.redboffin.worldhug.server.test.TestObject; did you forget to inherit a required module?
13:12:54.515 [ERROR] [org.redboffin.worldhug.Test] Errors in 'file:/C:/Documents%20and%20Settings/Darren/workspace/WorldHug/src/org/redboffin/worldhug/client/test/TestServiceAsync.java'
13:12:54.515 [ERROR] [org.redboffin.worldhug.Test] Line 12: No source code is available for type org.redboffin.worldhug.server.test.TestObject; did you forget to inherit a required module?
13:12:55.953 [ERROR] [org.redboffin.worldhug.Test] Errors in 'file:/C:/Documents%20and%20Settings/Darren/workspace/WorldHug/src/org/redboffin/worldhug/client/test/TestView.java'
13:12:55.968 [ERROR] [org.redboffin.worldhug.Test] Line 42: No source code is available for type org.redboffin.worldhug.server.test.TestObject; did you forget to inherit a required module?
13:12:55.968 [ERROR] [org.redboffin.worldhug.Test] Line 46: No source code is available for type org.redboffin.worldhug.server.test.InnerObject; did you forget to inherit a required module?
13:12:55.984 [ERROR] [org.redboffin.worldhug.Test] Line 48: No source code is available for type org.redboffin.worldhug.server.test.ListObject; did you forget to inherit a required module?
13:12:56.765 [INFO] [org.redboffin.worldhug.Test] Module org.redboffin.worldhug.Test has been loaded

以下是项目类和文件。

Test.gwt.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.0.0//EN" "http://google-web-toolkit.googlecode.com/svn/tags/2.0.0/distro-source/core/src/gwt-module.dtd">
<module>
    <inherits name="com.google.gwt.user.User" />
    <source path="client/test" />
    <entry-point class="org.redboffin.worldhug.client.test.Test"></entry-point>
</module>

Web.xml中

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>

  <!-- Servlets -->

  <servlet>
    <servlet-name>testServlet</servlet-name>
    <servlet-class>org.redboffin.worldhug.server.test.TestServiceImpl</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>testServlet</servlet-name>
    <url-pattern>/worldhug/test/testService</url-pattern>
  </servlet-mapping>

  <!-- Default page to serve -->
  <welcome-file-list>
    <welcome-file>test.html</welcome-file>
  </welcome-file-list>

</web-app>

TestObject.java

package org.redboffin.worldhug.server.test;

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

import com.google.gwt.user.client.rpc.IsSerializable;

public class TestObject implements IsSerializable {

    private String testObjectString;
    private InnerObject innerObject;
    private List<ListObject> listObjects = new ArrayList<ListObject>();

    public TestObject() {}

    // Getters and setters removed for brevity

}

InnerObject.java

package org.redboffin.worldhug.server.test;

import com.google.gwt.user.client.rpc.IsSerializable;

public class InnerObject implements IsSerializable {

    private String innerObjectString;

    public InnerObject() {}

        // Getters and setters removed for brevity

}

ListObject.java

package org.redboffin.worldhug.server.test;

import com.google.gwt.user.client.rpc.IsSerializable;

public class ListObject implements IsSerializable {

    private String listObjectString;

    public ListObject() {}

        // Getters and setters removed for brevity.

}

TestService.java

package org.redboffin.worldhug.client.test;

import org.redboffin.worldhug.server.test.TestObject;

import com.google.gwt.user.client.rpc.RemoteService;
import com.google.gwt.user.client.rpc.RemoteServiceRelativePath;

/**
 * The client side stub for the Test Service.
 * @author Darren
 */
@RemoteServiceRelativePath("testService")
public interface TestService extends RemoteService {

    TestObject test();

}

TestServiceAsync.java

package org.redboffin.worldhug.client.test;

import org.redboffin.worldhug.server.test.TestObject;

import com.google.gwt.user.client.rpc.AsyncCallback;

/**
 * The async counterpart of <code>TestService</code>.
 * @author Darren
 */
public interface TestServiceAsync {

    void test(AsyncCallback<TestObject> callback);

}

TestServiceImpl.java

package org.redboffin.worldhug.server.test;

import java.util.List;

import org.redboffin.worldhug.client.test.TestService;

import com.google.gwt.user.server.rpc.RemoteServiceServlet;

/**
 * The server side implementation of the RPC service.
 * @author Darren
 */
@SuppressWarnings("serial")
public class TestServiceImpl extends RemoteServiceServlet implements TestService {

    @Override
    public TestObject test() {

        TestObject testObject = new TestObject();       
        testObject.setTestObjectString("Test Object String");

        InnerObject innerObject = new InnerObject();
        innerObject.setInnerObjectString("Inner Object String");

                testObject.setInnerObject(innerObject);

        List<ListObject> listObjects = testObject.getListObjects();

        ListObject listObjectOne = new ListObject();
        listObjectOne.setListObjectString("List Object One");
        listObjects.add(0, listObjectOne);

        ListObject listObjectTwo = new ListObject();
        listObjectTwo.setListObjectString("List Object Two");
        listObjects.add(0, listObjectTwo);

        ListObject listObjectThree = new ListObject();
        listObjectThree.setListObjectString("List Object Three");
        listObjects.add(0, listObjectThree);

        return testObject;
    }

}

TestView.java

package org.redboffin.worldhug.client.test;

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

import org.redboffin.worldhug.server.test.InnerObject;
import org.redboffin.worldhug.server.test.ListObject;
import org.redboffin.worldhug.server.test.TestObject;

import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.uibinder.client.UiHandler;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.VerticalPanel;

public class TestView extends Composite {

    private static TestViewUiBinder uiBinder = GWT.create(TestViewUiBinder.class);

    interface TestViewUiBinder extends UiBinder<VerticalPanel, TestView> {}

    @UiField Label testObjectStringLabel;
    @UiField Label innerObjectStringLabel;
    @UiField VerticalPanel listObjectsPanel;
    @UiField Button button;
    @UiField Label errorMessageLabel;

    public TestView(String firstName) {
        initWidget(uiBinder.createAndBindUi(this));
    }

    @UiHandler("button")
    void onClick(ClickEvent e) {

        TestServiceAsync testService = (TestServiceAsync) GWT.create(TestService.class);

        AsyncCallback<TestObject> callback = new AsyncCallback<TestObject>() {

            public void onSuccess(TestObject testObject) {
                testObjectStringLabel.setText(testObject.getTestObjectString());
                InnerObject innerObject = testObject.getInnerObject();
                innerObjectStringLabel.setText(innerObject.getInnerObjectString());
                ArrayList<ListObject> listObjects = (ArrayList<ListObject>) testObject.getListObjects();
                Iterator<ListObject> iterator = listObjects.iterator();
                while(iterator.hasNext()) {
                    ListObject listObject = (ListObject) iterator.next();
                    listObjectsPanel.add(new Label(listObject.getListObjectString()));
                }
            }

            public void onFailure(Throwable caught) {
                errorMessageLabel.setText("Error : "+caught.getMessage());
            }
          };

          testService.test(callback);

    }

}

TestView.ui.xml

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder 
    xmlns:ui="urn:ui:com.google.gwt.uibinder"
    xmlns:g="urn:import:com.google.gwt.user.client.ui">

    <g:VerticalPanel>
        <g:Label>Test Object</g:Label>
        <g:Label ui:field="testObjectStringLabel"></g:Label>
        <g:VerticalPanel>
            <g:Label>Inner Object</g:Label>
            <g:Label ui:field="innerObjectStringLabel"></g:Label>
        </g:VerticalPanel>
        <g:VerticalPanel ui:field="listObjectsPanel">
            <g:Label>List Objects</g:Label>
        </g:VerticalPanel>
        <g:Button ui:field="button">Display Test Object</g:Button>
        <g:Label ui:field="errorMessageLabel"></g:Label>
    </g:VerticalPanel>

</ui:UiBinder>

感谢您阅读此内容以及您可以给我（和其他人）的任何帮助。

Answer 1

您需要识别包含要进行GWT编译的源的所有包。

e.g。

<source path="client/test"/>
<source path="server/test"/>

将域类不在服务器包中可能是更好的选择。我们经常这样做：

<source path="client"/>
<source path="shared"/>

其中shared包含在客户端和服务器之间来回传递的DTO。

Answer 2

如果使用DTO，则必须在共享文件夹（约定）中插入可转让对象。如果使用域对象非共享而不是“传输”，则可以在服务器文件夹中插入文件夹（例如“域”），但此“类型”不能用于异步调用。道德：如果一个对象被转移必须“共享”，否则你可以安全地使用在服务器文件夹中。