基于GWT+Guice+gwt-dispatch的范例

GWT默认的RPC是一个RPC对应一个Servlet，如果需要实现增删改查功能，至少就得做4个servlet，每个servlet实现一个功能，然后还得在web.xml里注册这组servlet。

gwt-dispatch用比较简单的办法实现了更简单的办法。

下面做一个小例子，实现了两个RPC功能。

功能1：根据输入的名字，前面加hello字样然后输出。
功能2：根据输入的字符，直接输出输入的字符。

里面有下面几个概念，理解了就不难了

ActionHandler：gwt-disptach RPC的处理器，每个功能都要有一个ActionHandler的子类，通过ActionHandler来处理业务功能。
Action：相当与ActionHandler的传入参数对象，所有参数都通过Action传入给ActionHandler来处理。
Result：相当与处理后的返回结果，ActionHandler处理后，要用对象的方式返回Result的实例。

环境：

os：ubuntu 11.10
jdk：Linux jim-laptop 3.0.0-17-generic #30-Ubuntu SMP Thu Mar 8 20:45:39 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
gwt：2.4.0
gwt-disptach：1.2.0
顶级包目录：com.demo

ok，别的不说了，上代码

com.demo.Gwt_guice_dispatcher_demo1.gwt.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "//gwt-module/" "http://google-web-toolkit.googlecode.com/svn/tags/1.6.2/distro-source/core/src/gwt-module.dtd">
<module rename-to='gwt_guice_dispatcher_demo1'>
 <inherits name='com.google.gwt.user.User'/>
 <inherits name='com.google.gwt.user.theme.clean.Clean'/>
 <inherits name='net.customware.gwt.dispatch.Dispatch' />
 <source path='client'/>
 <source path='shared'/>
 <entry-point class="com.demo.client.MainEntry" />
</module>

MainDispatchServletModule.java 

package com.demo.server;

import net.customware.gwt.dispatch.server.guice.GuiceStandardDispatchServlet;

import com.google.inject.servlet.ServletModule;

public class MainDispatchServletModule extends ServletModule {
 @Override
 protected void configureServlets() {
  //gwt_guice_dispatcher_demo1必须和gwt.xml中rename-to的名字一样
  serve("/gwt_guice_dispatcher_demo1/dispatch").with(GuiceStandardDispatchServlet.class);
 }
}

Hello处理的几个类
HelloAction.java 

package com.demo.shared;

import net.customware.gwt.dispatch.shared.Action;

public class EchoAction implements Action {
 private String message;

 public EchoAction() {
  this.message = "";
 }

 public String getMessage() {
  return message;
 }

 public void setMessage(String message) {
  this.message = message;
 } 
}

HelloResult.java 

package com.demo.shared;

import net.customware.gwt.dispatch.shared.Result;

public class EchoResult implements Result {
 private String message;

 public EchoResult() {
 }

 public String getMessage() {
  return message;
 }

 public void setMessage(String message) {
  this.message = message;
 }
}

HelloHandler.java 

package com.demo.server.handler;

import com.demo.shared.HelloAction;
import com.demo.shared.HelloResult;

import net.customware.gwt.dispatch.server.ActionHandler;
import net.customware.gwt.dispatch.server.ExecutionContext;
import net.customware.gwt.dispatch.shared.ActionException;

public class HelloHandler implements ActionHandler {
 @Override
 public HelloResult execute(HelloAction action, ExecutionContext context) throws ActionException {
  HelloResult result = new HelloResult();
  result.setMessage("你好 " + action.getName());
  return result;
 }

 @Override
 public Class getActionType() {
  return HelloAction.class; //返回Action类的类型
 }

 @Override
 public void rollback(HelloAction action, HelloResult result, ExecutionContext context) throws ActionException {
  //
 }
}

和Echo有关的三个类 
EchoAction.java 

package com.demo.shared;

import net.customware.gwt.dispatch.shared.Action;

/**
 * Action相当于RPC调用所需的入参
 * @author jim
 *
 */
public class HelloAction implements Action {
 private static final long serialVersionUID = 1054848714093248343L;
 private String name;

 public HelloAction() {
  //必须有默认构造，否则无法序列化
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }
}

EchoResult.java 

package com.demo.shared;

import net.customware.gwt.dispatch.shared.Result;

/**
 * Action相当于RPC调用后的返回值
 * @author jim
 *
 */
public class HelloResult implements Result {
 private static final long serialVersionUID = -2469468297641898770L;
 private String message;
 public HelloResult(){
  //必须有默认构造，否则无法序列化
 }

 public String getMessage() {
  return message;
 }

 public void setMessage(String message) {
  this.message = message;
 }
}

EchoHandler.java 

package com.demo.server.handler;

import com.demo.shared.EchoAction;
import com.demo.shared.EchoResult;

import net.customware.gwt.dispatch.server.ActionHandler;
import net.customware.gwt.dispatch.server.ExecutionContext;
import net.customware.gwt.dispatch.shared.DispatchException;

public class EchoHandler implements ActionHandler {
 @Override
 public EchoResult execute(EchoAction action, ExecutionContext context) throws DispatchException {
  EchoResult result = new EchoResult();
  result.setMessage(action.getMessage());
  return result;
 }

 @Override
 public Class getActionType() {
  return EchoAction.class;
 }

 @Override
 public void rollback(EchoAction action, EchoResult result, ExecutionContext context) throws DispatchException {
  //
 }
}

和Guice有关的Listener
GWTDispatcherServletContextListener.java 

package com.demo.server;

import net.customware.gwt.dispatch.server.guice.ActionHandlerModule;
import net.customware.gwt.dispatch.server.guice.ServerDispatchModule;

import com.demo.server.handler.EchoHandler;
import com.demo.server.handler.HelloHandler;
import com.demo.shared.EchoAction;
import com.demo.shared.HelloAction;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.servlet.GuiceServletContextListener;

public class GWTDispatcherServletContextListener extends GuiceServletContextListener {
 @Override
 protected Injector getInjector() {
  return Guice.createInjector(new ServerDispatchModule(), new MainDispatchServletModule(), new ActionHandlerModule() {
   @Override
   protected void configureHandlers() {
    bindHandler(HelloAction.class, HelloHandler.class);
    bindHandler(EchoAction.class, EchoHandler.class);
   }
  });
 }
}

web.xml 

<pre class="xml">
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
              http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5"
         xmlns="http://java.sun.com/xml/ns/javaee">
 <filter>
  <filter-name>guiceFilter</filter-name>
  <filter-class>com.google.inject.servlet.GuiceFilter</filter-class>
 </filter>
 <filter-mapping>
  <filter-name>guiceFilter</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>
 <listener>
  <listener-class>com.demo.server.GWTDispatcherServletContextListener</listener-class>
 </listener>

 <welcome-file-list>
   <welcome-file>Gwt_guice_dispatcher_demo1.html</welcome-file>
 </welcome-file-list>
</web-app>

Gwt_guice_dispatcher_demo1.html 

<!doctype html>
<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <link type="text/css" rel="stylesheet" href="Gwt_guice_dispatcher_demo1.css">
    <title>gwt_guice_dispatcher_demo1</title>
    <script type="text/javascript" language="javascript" src="gwt_guice_dispatcher_demo1/gwt_guice_dispatcher_demo1.nocache.js"></script>
  </head>
  <body>

  </body>
</html>

Gwt_guice_dispatcher_demo1.css 就不贴了，内容是google gwt plugin自动生成的，就算不要也不影响应用

主程序 EntryPoint MainEntry.java 

package com.demo.client;

import net.customware.gwt.dispatch.client.DefaultExceptionHandler;
import net.customware.gwt.dispatch.client.DispatchAsync;
import net.customware.gwt.dispatch.client.standard.StandardDispatchAsync;

import com.demo.shared.EchoAction;
import com.demo.shared.EchoResult;
import com.demo.shared.HelloAction;
import com.demo.shared.HelloResult;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
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.RootPanel;
import com.google.gwt.user.client.ui.TextBox;

public class MainEntry implements EntryPoint {
 private final DispatchAsync dispatch = new StandardDispatchAsync(new DefaultExceptionHandler());
 @Override
 public void onModuleLoad() {
  RootPanel.get().clear();
  final TextBox txtName = new TextBox();
  RootPanel.get().add(txtName);
  Button btnHello = new Button("按钮1");
  RootPanel.get().add(btnHello);
  btnHello.addClickHandler(new ClickHandler() {
   @Override
   public void onClick(ClickEvent event) {
    HelloAction action = new HelloAction();
    action.setName(txtName.getText());
    dispatch.execute(action, new AsyncCallback() {
     @Override
     public void onSuccess(HelloResult result) {
      Window.alert(result.getMessage());
     }

     @Override
     public void onFailure(Throwable caught) {
      
     }
    });
   }
  });

  Button btnEcho = new Button("Echo");
  btnEcho.addClickHandler(new ClickHandler() {
   @Override
   public void onClick(ClickEvent event) {
    EchoAction action = new EchoAction();
    action.setMessage(txtName.getText());
    dispatch.execute(action, new AsyncCallback() {
     @Override
     public void onFailure(Throwable caught) {
      //
     }

     @Override
     public void onSuccess(EchoResult result) {
      Window.alert(result.getMessage());
     }
    });
   }
  });
  RootPanel.get().add(btnEcho);
 }
}

ok，好了，就这些了。