GWT与SPRING整合

1. 我们这里整合spring主要是用到了一个组件gwt-widgets-server  可以在http://jaist.dl.sourceforge.net/sourceforge/gwt-widget/gwt-widgets-server-0.1.2-bin.zip下载。
2. 我们使用gwt的命令(projectCreator applicationCreator )生成gwt的eclipse项目，参见：http://code.google.com/webtoolkit/gettingstarted.html  
3. 导入eclipse中，导入后请看附件1.
4. 分析代码
首先看web.xml




   1. xml version="1.0" encoding="UTF-8"?> 
   2. <web-app> 
   3.  
   4.     <servlet> 
   5.         <servlet-name>GWTSpringservlet-name> 
   6.         <servlet-class> 
   7.             org.springframework.web.servlet.DispatcherServlet 
   8.         servlet-class> 
   9.         <load-on-startup>1load-on-startup> 
  10.     servlet> 
  11.  
  12.     <servlet-mapping> 
  13.         <servlet-name>GWTSpringservlet-name> 
  14.         <url-pattern>*.rpcurl-pattern> 
  15.     servlet-mapping> 
  16.     <servlet> 
  17.         <servlet-name>shellservlet-name> 
  18.         <servlet-class>com.google.gwt.dev.shell.GWTShellServletservlet-class> 
  19.     servlet> 
  20.      
  21.     <servlet-mapping> 
  22.         <servlet-name>shellservlet-name> 
  23.         <url-pattern>/static/*url-pattern> 
  24.     servlet-mapping> 
  25.      
  26. web-app> 


可以看到我们增加了段GWTSpring的servlet配置，熟悉spring-web的朋友一眼就可以看出。gwt-widgets-server 正是使用了spring-web的control来做gwt的remoteServiceServlet的。他是使用了cglib或者javassist 来动态使我们的Sevice class继承RemoteServiceServlet。细心的朋友可以看到代码中的粗体部分，本来直接生成的gwt模版是"/*"的url- pattern。但是我这里为什么要在前面加上"/static"部分呢？请让我在后面为你解释。下面看看GWTSpring-servlet.xml的配置。



   1. xml version="1.0" encoding="UTF-8"?> 
   2.  
   3. > 
   4.  
   5. <beans> 
   6.     <bean id="urlMapping" class="org.gwtwidgets.server.spring.GWTHandler" depends-on="userServiceTarget"> 
   7.         <property name="mapping"> 
   8.             <map> 
   9.                 <entry key="/userService.rpc" value-ref="userService" /> 
  10.             map> 
  11.         property> 
  12.         <property name="usingInstrumentation" value="false" /> 
  13.         <property name="unwrappingGWTExceptions" value="true" /> 
  14.        
  15.             You can specify your own class enhancer here 
  16.             <property name="classEnhancer"> 
  17.             <bean class="org.gwtwidgets.server.spring.enhancer.JavassistEnhancer"/> 
  18.             property> 
  19.         --> 
  20.     bean> 
  21.  
  22.     <bean id="userServiceTarget" class="com.javaeye.dengyin2000.truck.server.impl.UserServiceImpl"> 
  23.     bean> 
  24.     <bean id="userService" class="org.springframework.aop.framework.ProxyFactoryBean"> 
  25.         <property name="target" ref="userServiceTarget" /> 
  26.         <property name="autodetectInterfaces" value="true" /> 
  27.         <property name="interceptorNames"> 
  28.             <list> 
  29.                 <value>requestSettervalue> 
  30.             list> 
  31.         property> 
  32.     bean> 
  33.  
  34.     <bean id="requestSetter" 
  35.         class="org.gwtwidgets.server.spring.RequestInjection"> 
  36.         <property name="requestSetterName" value="setRequest" /> 
  37.         <property name="responseSetterName" value="setResponse" /> 
  38.     bean> 
  39. beans> 



我们配置了一个“/userService.rpc”的servlet mapping。你应该可以想到这个url应该就是gwt的RemoteServiceServlet的url。我不想多解释配置里面的内容，因为我也是抄的，如果仔细看的话应该可以明白，如果不明白的话可以看看gwt-widgets-server的源码。这段配置里面主要就是初始化了一个gwt的RemoteServiceServlet。他可以是任何的object。不需要显示的继承RemoteServiceServlet，一切都让org.gwtwidgets.server.spring.GWTHandler 帮你解决吧。他还帮你在RemoteServiceServlet注入了httpServletRequest 和 httpServletResponse。你不需要使用通过RemoteServiceServlet.getThreadLocalRequest() 去取。下面看看UserServiceImpl

java 代码

   1. package com.javaeye.dengyin2000.truck.server.impl; 
   2.  
   3. import javax.servlet.ServletRequest; 
   4. import javax.servlet.ServletResponse; 
   5. import javax.servlet.http.HttpServletRequest; 
   6.  
   7. import com.javaeye.dengyin2000.truck.client.server.UserService; 
   8.  
   9. public class UserServiceImpl implements UserService { 
  10.  
  11.     private static ThreadLocal servletRequest = new ThreadLocal(); 
  12.  
  13.     private static ThreadLocal servletResponse = new ThreadLocal(); 
  14.  
  15.     public void setRequest(ServletRequest request) { 
  16.         servletRequest.set(request); 
  17.     } 
  18.  
  19.     public void setResponse(ServletResponse request) { 
  20.         servletResponse.set(request); 
  21.     } 
  22.  
  23.     protected HttpServletRequest getRequest() { 
  24.         return (HttpServletRequest) servletRequest.get(); 
  25.     } 
  26.  
  27.     public boolean checkUser(String userName, String password) { 
  28.         if ("denny".equals(userName) && "123456".equals(password)) { 
  29.             getRequest().getSession().setAttribute("user", userName); 
  30.             return Boolean.TRUE; 
  31.         } 
  32.         return Boolean.FALSE; 
  33.     } 
  34.  
  35. } 


这里面有个checkUser方法。在这里我发现了一个问题。gwt-widgets-server中的例子上面setRequest和 setResponse方法里面的参数的类型是HttpServletRequest和HttpServletResponse但是这样的话，requst和response不能被注入。清看gwt-widgets-server中的RequestInjection class

java 代码


   1. package org.gwtwidgets.server.spring; 
   2.  
   3. import java.lang.reflect.Method; 
   4.  
   5. import javax.servlet.ServletRequest; 
   6. import javax.servlet.ServletResponse; 
   7. import javax.servlet.http.HttpServletRequest; 
   8. import javax.servlet.http.HttpServletResponse; 
   9.  
  10. import org.aopalliance.intercept.MethodInterceptor; 
  11. import org.aopalliance.intercept.MethodInvocation; 
  12.  
  13. /**
  14.  * Method interceptor that injects the current {@link HttpServletRequest} and
  15.  * the current {@link HttpServletResponse} via reflection to a target. You must specify
  16.  * the setter names via {@link #setRequestSetterName(String)} and {@link #setResponseSetterName(String)}
  17.  * otherwise they will fail silently. These setters can and must have only a single argument
  18.  * namely {@link ServletRequest} and {@link ServletResponse} respectively.
  19.  * 
  20.  * @author George Georgovassilis
  21.  * 
  22.  */ 
  23. public class RequestInjection implements MethodInterceptor { 
  24.  
  25.     protected String requestSetterName; 
  26.  
  27.     protected String responseSetterName; 
  28.  
  29.     private void setRequestOnTarget(HttpServletRequest request, HttpServletResponse response, Object target) 
  30.         throws Exception { 
  31.     if (requestSetterName != null) 
  32.         try { 
  33.         Method method = target.getClass().getMethod(requestSetterName, 
  34.             new Class[] { ServletRequest.class }); 
  35.         method.invoke(target, new Object[] { request }); 
  36.         } catch (NoSuchMethodException e) { 
  37.         } 
  38.     if (responseSetterName != null) 
  39.         try { 
  40.         Method method = target.getClass().getMethod(responseSetterName, 
  41.             new Class[] { ServletResponse.class }); 
  42.         method.invoke(target, new Object[] { response }); 
  43.         } catch (NoSuchMethodException e) { 
  44.         } 
  45.     } 
  46.  
  47.     public Object invoke(MethodInvocation invocation) throws Throwable { 
  48.     Object target = invocation.getThis(); 
  49.     setRequestOnTarget(GWTSpringController.getRequest(), GWTSpringController.getResponse(), target); 
  50.     return invocation.proceed(); 
  51.     } 
  52.  
  53.     /**
  54.          * Specify the name of the setter method that can be invoked to set the
  55.          * current request and response on the target. If the method does not
  56.          * exist on the target, it is silently discarded.
  57.          * 
  58.          * @param setterName
  59.          */ 
  60.     public void setRequestSetterName(String setterName) { 
  61.     this.requestSetterName = setterName; 
  62.     } 
  63.  
  64.     /**
  65.          * Specify the name of the setter method that can be invoked to set the
  66.          * current response on the target. If the method does not exist on the
  67.          * target, it is silently discarded.
  68.          * 
  69.          * @param setterName
  70.          */ 
  71.     public void setResponseSetterName(String setterName) { 
  72.     this.responseSetterName = setterName; 
  73.     } 
  74.  
  75. } 


请看上面的粗体部分他这里取的参数类型是ServletRequest和ServletResponse。所以我把UserServiceImpl中的 setRequest和setResponse类型改成了ServletRequest和ServletResponse。在getRequest中 cast成HttpServletRequest。ok，看看在gwt的client中怎么调用吧。

java 代码


   1. package com.javaeye.dengyin2000.truck.client; 
   2.  
   3. import com.google.gwt.core.client.EntryPoint; 
   4. import com.google.gwt.core.client.GWT; 
   5. import com.google.gwt.user.client.Window; 
   6. import com.google.gwt.user.client.rpc.AsyncCallback; 
   7. import com.google.gwt.user.client.rpc.ServiceDefTarget; 
   8. import com.google.gwt.user.client.ui.Button; 
   9. import com.google.gwt.user.client.ui.ClickListener; 
  10. import com.google.gwt.user.client.ui.DockPanel; 
  11. import com.google.gwt.user.client.ui.FlexTable; 
  12. import com.google.gwt.user.client.ui.HTML; 
  13. import com.google.gwt.user.client.ui.PasswordTextBox; 
  14. import com.google.gwt.user.client.ui.RootPanel; 
  15. import com.google.gwt.user.client.ui.TextBox; 
  16. import com.google.gwt.user.client.ui.Widget; 
  17. import com.javaeye.dengyin2000.truck.client.server.UserService; 
  18. import com.javaeye.dengyin2000.truck.client.server.UserServiceAsync; 
  19.  
  20. /**
  21.  * Entry point classes define onModuleLoad().
  22.  */ 
  23. public class TruckApp implements EntryPoint { 
  24.     private TextBox userName; 
  25.  
  26.     private PasswordTextBox password; 
  27.  
  28.     private Button submit; 
  29.  
  30.     private FlexTable loginTable; 
  31.  
  32.     public static final HTML HEAD_TITLE = new HTML("); 
  33.  
  34.     private UserServiceAsync userService; 
  35.  
  36.     /**
  37.      * This is the entry point method.
  38.      */ 
  39.     public void onModuleLoad() { 
  40.          
  41.         DockPanel panel = new DockPanel(); 
  42.         panel.setVerticalAlignment(DockPanel.ALIGN_MIDDLE); 
  43.         panel.setHorizontalAlignment(DockPanel.ALIGN_CENTER); 
  44.         submit = new Button("提交"); 
  45.         submit.addClickListener(new ClickListener(){ 
  46.  
  47.             public void onClick(Widget sender) { 
  48.                 // TODO check the user for validate 
  49.                 getUserClientService().checkUser(userName.getText(), password.getText(), new AsyncCallback(){ 
  50.  
  51.                     public void onFailure(Throwable caught) { 
  52.                         Window.alert("Server error!"); 
  53.                     } 
  54.  
  55.                     public void onSuccess(Object result) { 
  56.                         if (((Boolean)result).booleanValue() == true){ 
  57.                             Window.alert("Login successfully!"); 
  58.                         }else{ 
  59.                             Window.alert("Login failed!"); 
  60.                         } 
  61.                     } 
  62.                      
  63.                 }); 
  64.             } 
  65.              
  66.         }); 
  67.  
  68.         userName = new TextBox(); 
  69.         password = new PasswordTextBox(); 
  70.  
  71.         loginTable = createLoginTable(); 
  72.  
  73.         panel.setWidth("100%"); 
  74.         panel.setHeight("100%"); 
  75.          
  76.         loginTable.setWidget(2, 0, submit); 
  77.         panel.add(loginTable, DockPanel.CENTER); 
  78.         panel.add(HEAD_TITLE, DockPanel.NORTH); 
  79.          
  80.         RootPanel.get().add(panel); 
  81.     } 
  82.  
  83.     private FlexTable createLoginTable() { 
  84.         FlexTable table = new FlexTable(); 
  85.         table.setText(0, 0, "用户名:"); 
  86.         table.setWidget(0, 1, userName); 
  87.         table.setText(1, 0, "密  码:"); 
  88.         table.setWidget(1, 1, password); 
  89.         table.setStyleName("ks-layouts-Label"); 
  90.         return table; 
  91.     } 
  92.      
  93.     private UserServiceAsync getUserClientService(){ 
  94.         if (userService == null){ 
  95.             userService = (UserServiceAsync) GWT.create(UserService.class); 
  96.             ServiceDefTarget endPoint = (ServiceDefTarget) userService; 
  97.             String moduleRelativeURL = "/userService.rpc"; 
  98.             endPoint.setServiceEntryPoint(moduleRelativeURL); 
  99.         } 
100.         return userService; 
101.     } 
102. } 


java 代码


   1. package com.javaeye.dengyin2000.truck.client.server; 
   2.  
   3. import com.google.gwt.user.client.rpc.RemoteService; 
   4.  
   5. public interface UserService extends RemoteService { 
   6.     boolean checkUser(String userName, String password); 
   7. } 


java 代码


   1. package com.javaeye.dengyin2000.truck.client.server; 
   2.  
   3. import com.google.gwt.user.client.rpc.AsyncCallback; 
   4.  
   5. public interface UserServiceAsync { 
   6.     void checkUser(String userName, String password, AsyncCallback callback); 
   7. } 


ok。到此配置结束。对了好像还忘了解释为什么要在web.xml中加上/static这段。原因是如果shell的url-pattern是/*的话，就会handler了gwt的RemoteServiceServlet的路径，这样的话remote rpc调用就总是Server error了。这时我们访问地址需要变成http://localhost:8888/static /com.javaeye.dengyin2000.truck.TruckApp/TruckApp.html 这样了。我提交了整个eclipse gwt项目所有代码但是把require lib去掉了。 需要的lib是spring-1.2.8.jar log4j-1.2.13.jar javassist-3.0.jar gwt-widgets-server-0.1.2.jar gwt-servlet.jar commons-logging-1.1.jar cglib-nodep-2.1_3.jar。请自行下载然后放到eclipse项目中的tomcat\webapps\ROOT\WEB-INF \lib\下面。你还需要把项目中引用到gwt lib的路径换成你自己机子上的。