Common problems and solutions in the GWT user framework

GWT (Google Web Toolkit) is a development framework for building web -based applications.Although GWT provides many convenient functions, it is still possible to encounter some common problems during use.The following will introduce some common GWT issues and their solutions, and provide some Java code examples. 1. Question: How to use RPC in GWT (remote process call)? Solution: GWT's RPC mechanism allows the client to communicate with the server.First, a service interface that needs to be created from the RemoteService interface.Then implement this interface on the server side and use @remoteServiceReellatePath to annotate the relative path of the specified service.Finally, create an agent object that inherits the RemoteServiceProxy on the client, and uses the GWT.CREATE () method to create an instance.The following is an example: // Service interface public interface MyService extends RemoteService { void doSomething(String parameter); } // Service implementation @RemoteServiceRelativePath("myservice") public class MyServiceImpl extends RemoteServiceServlet implements MyService { public void doSomething(String parameter) { // Execute service logic } } // Client proxy public interface MyServiceAsync { void doSomething(String parameter, AsyncCallback<Void> callback); } MyServiceAsync service = GWT.create(MyService.class); service.doSomething("example", new AsyncCallback<Void>() { public void onSuccess(Void result) { // Successful processing logic } public void onFailure(Throwable caught) { // Failure processing logic } }); 2. Question: How to handle the browser historical record in GWT? Solution: GWT provides a History mechanism that enables the URL of the application to establish a connection with user operations.First of all, you need to add a `Inherits>` tag to the module xml file to declare the History module.Then, call the `history.newitem (token)` where the historical record is required, where the "Token" is a string used to identify the state.Finally, add an event processing program to handle the changes in historical records with `History.addvalueChangehandler ()`.The following is an example: // Statement using the History module <inherits name='com.google.gwt.user.History' /> // Record historical records History.newItem("page1"); // Add event processing procedures for changing historical records History.addValueChangeHandler(new ValueChangeHandler<String>() { public void onValueChange(ValueChangeEvent<String> event) { String token = event.getValue(); // Treat different page status according to token if (token.equals("page1")) { // Processing page 1 logic } else if (token.equals("page2")) { // Processing page 2 logic } } }); 3. Question: How to use GWT with a third -party JavaScript library for integration? Solution: GWT provides JSINTEROP (JavaScript interoperability) mechanism, which can be integrated with the existing JavaScript library.First of all, you need to use the naming space of the JavaScript library to be accessed by the `@jspackage`.Then use the interface between Java and JavaScript with `@jstype`.Finally, use the interface in the GWT project.The following is an example: // Use the naming space of the JavaScript library @JsPackage(namespace = "google.maps") public class Maps { // State the javascript function public static native void initialize(String divId) /*-{ $wnd.google.maps.Map(divId, { center: { lat: -34.397, lng: 150.644 }, zoom: 8 }); }-*/; } // Use JavaScript function Maps.initialize("mapDiv"); The above are some common GWT problems and their solutions.It is hoped to help developers using GWT development.