关于jsp的简介以及优点和缺点

JSP(JavaServer Pages)是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准。JSP技术有点类似ASP技术，它是在传统的网页HTML文件(*.htm,*.html)中插入Java程序段(Scriptlet)和JSP标记(tag)，从而形成JSP文件(*.jsp)。 用JSP开发的Web应用是跨平台的，即能在Linux下运行，也能在其他操作系统上运行。JSP技术使用Java编程语言编写类XML的tags和scriptlets，来封装产生动态网页的处理逻辑。网页还能通过tags和scriptlets访问存在于服务端的资源的应用逻辑。JSP将网页逻辑与网页设计和显示分离，支持可重用的基于组件的设计，使基于Web的应用程序的开发变得迅速和容易。 XML-like tags and scriptlets to encapsulate the processing logic for generating dynamic web pages. Pages can also access the application logic of resources residing on the server through tags and scriptlets. JSP separates the page logic from the webpage design and display, enabling reusable component-based designs, making web application development faster and easier. When a web server encounters a request to access a JSP page, it first executes the embedded Java program segments and then returns the execution results along with the HTML code in the JSP file to the client. The inserted Java program segments can interact with databases, redirect webpages, and perform various functions required to build dynamic web pages. Similar to Java Servlets, JSP runs on the server side and typically returns an HTML text response to the client's browser. JSP's 1.0 specification was finalized in September 1999, followed by the 1.1 specification in December of the same year. The latest version at the time of writing was JSP 2.0, with a draft for JSP 2.0 already in circulation. JSP pages consist of HTML code combined with embedded Java code. The server processes the Java code when the page is requested by a client and sends back the generated HTML to the browser. Java Servlets serve as the foundation for JSP technology, and large-scale web applications often require the combination of Servlets and JSPs for comprehensive development. JSP inherits the simplicity, full object-oriented nature, platform independence, and security reliability of the Java language, making it well-suited for internet-based applications. **JSP Technology Advantages:** 1. **Platform Independence**: Once written, JSP code can be deployed on any platform that supports Java, ensuring a consistent user experience across different environments. 2. **Scalability**: JSP applications can easily scale from a simple setup to complex, distributed architectures involving clustering and load balancing, as well as transaction handling and message processing. 3. **Rich Development Tools**: A variety of powerful and feature-rich development tools are available for JSP, many of which can be obtained free of charge and work seamlessly across multiple platforms. **JSP Technology Disadvantages:** 1. **Complexity**: The very features that enable JSP's platform independence and scalability can also make it more complex to develop and maintain compared to simpler technologies like ASP or PHP. 2. **Performance**: JSP's performance can be impacted due to the need to keep class files in memory, which may lead to higher resource usage, especially in terms of memory and disk space for storing .java and .class files. In conclusion, JSP is a robust and versatile technology for creating dynamic web applications. Its strengths lie in its platform independence, scalability, and rich toolset, while its weaknesses include added complexity and potential performance concerns. As with any technology choice, developers must weigh these pros and cons against their specific project requirements to determine if JSP is the right fit for their needs.