tailieunhanh - ColdFusion Developer’s Guide phần 3

Xin lưu ý rằng nội dung trong hướng dẫn này được bảo vệ theo luật bản quyền ngay cả khi nó không phải là phân phối cùng với phần mềm bao gồm một thỏa thuận giấy phép người sử dụng. Nội dung của hướng dẫn này được trang bị để sử dụng thông tin, có thể thay đổi mà không cần thông báo, và không nên được hiểu như là một cam kết của | ADOBE COLDFUSION 8 227 ColdFusion Developer s Guide Using application event handlers The following table briefly describes the application event CFC methods that you can implement including when they are triggered. The following sections describe how to use these methods in more detail. Method When run onApplicationStart The application first starts when the first request for a page is processed or the first CFC method is invoked by an event gateway instance Flash Remoting request or a web service invocation. This method is useful for setting application-wide Application scope variables such as the names of data sources. onApplicationEnd The application ends when the application times out or the server shuts down. onSessionStart A new session is created as a result of a request that is not in an existing session including ColdFusion event gateway sessions. The application must enable sessions for this event to happen. onSessionEnd A session time-out setting is reached. This event is not triggered when the application ends or the server shuts down. onRequestStart ColdFusion receives any of the following a request an HTTP request for example from a browser a message to an event gateway a SOAP request or a Flash Remoting request. onRequest The onRequestStart event has completed. This method can act as a filter for the requested page content. onRequestEnd All pages and CFCs in the request have been processed equivalent to the page. onMissingTemplate When ColdFusion receives a request for a nonexistent page. onError When an exception occurs that is not caught by a try catch block. When ColdFusion receives a request it instantiates the Application CFC and runs the code in the following order CFC initialization code at the top of the file onApplicationStart if not run before for this application onSessionStart if not run before for this session onRequestStart onRequest or the requested page if there is no onRequest method onRequestEnd The