Servlet和JSP技术简述

Servlet和JSP技术简述(中文3500字,英文2400字)
1.1 Servlet的功能
Servlets是运行在Web或应用服务器上的Java程序，它是一个中间层，负责连接来自Web浏览器或其他HTTP客户程序的请求和HTTP服务器上的数据库或应用程序。Servlet的工作是执行西门的任务。
1.读取客户发送的显式数据。
最终用户一般在页面的HTML表单中输入这些数据。然而，数据还有可能来自applet或定制的HTTP客户程序。
2.读取由浏览器发送的隐式请求数据。

附录Ⅰ
An Overview of Servlet and JSP Technology
1.1  A Servlet's Job
Servlets are Java programs that run on Web or application servers, acting as a middle layer between requests coming from Web browsers or other HTTP clients and databases or applications on the HTTP server. Their job is to perform the following tasks.
1．Read the explicit data sent by the client.
The end user normally enters this data in an HTML form on a Web page. However, the data could also come from an applet or a custom HTTP client program.
2．Read the implicit HTTP request data sent by the browser.
Figure 1-1 shows a single arrow going from the client to the Web server (the layer where servlets and JSP execute), but there are really two varieties of data: the explicit data that the end user enters in a form and the behind-the-scenes HTTP information. Both varieties are critical. The HTTP information includes cookies, information about media types and compression schemes the browser understands, and so on.