jsp應(yīng)用框架外文翻譯-jsp程序-在線瀏覽
2025-03-24 06:39本頁面
【正文】 oducts. A framework provides developers with a set of backbone ponents that have the following characteristics: are known to work well in other applications. 2. They are ready to use with the next project. 3. They can also be used by other teams in the anization. Frameworks are the classic buildversusbuy proposition. If you build it, you will understand it when you are done— but how long will it be before you can roll your own? If you buy it, you will have to climb the learning curve— and how long is that going to take? There is no right answer here, but most observers would agree that frameworks such as Struts provide a significant return on investment pared to starting from scratch, especially for larger projects. Enabling technologies: Applications developed with Struts are based on a number of enabling technologies. These ponents are not specific to Struts and underlie every Java web application. A reason that developers use frameworks like Struts is to hide the nasty details behind acronyms like HTTP, CGI, and JSP. As a Struts developer, you don’t need to be an alphabet soup guru, but a working knowledge of these base technologies can help you devise creative solutions to tricky problems. Java servlets: Sun’s Java Servlet platform directly addresses the two main drawbacks of CGI , servlets offer better performance and utilization of resources than conventional CGI programs. Second, the writeonce, runanywhere nature of Java means that servlets are portable between operating systems that have a Java Virtual Machine (JVM). A servlet looks and feels like a miniature web server. It receives a request and renders a 大連交通大學(xué)信息工程學(xué)院 2021 屆本科生畢業(yè)設(shè)計（論文）外文翻譯 2 response. But, unlike conventional web servers, the servlet application programming interface (API) is specifically designed to help Java developers create dynamic applications. The servlet itself is simply a Java class that has been piled into byte code, like any other Java object. The servlet has access to a rich API of HTTPspecific services, but it is still just another Java object running in an application and can leverage all your other Java assets. To give conventional web servers access to servlets, the servlets are plugged into containers. The servlet container is attached to the web server. Each servlet can declare what URL patterns it would like to handle. When a request matching a registered pattern arrives, the web server passes the request to the container, and the container invokes the servlet. But unlike CGI programs, a new servlet is not created for each request. Once the container instantiates the servlet, it will just create a new thread for each request. Java threads are much less expensive than the server processes used by CGI programs. Once the servlet has been created, using it for additional requests incurs very little overhead. Servlet developers can use the init() method to hold references to expensive resources, such as database connections or EJB Home Interfaces, so that they can be shared between requests. Acquiring resources like these can take several seconds— which is lon
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