What language is the servlet technology developed in? What kind of packages and classes does it need

Servlets are used for web development and as a control layer to process user requests. Servlet is the foundation of BS development, and understanding Servlet will be of great help to you in the future, JSP, and the later Struts2 framework. In normal operation, servlets are not used much, and all of them use struts2 instead of servlets to complete the functions.

You can understand it this way, when you click on a link on a web page, you will submit a request like a server, and this request is divided into two types, one is a POST request and the other is a get request. The corresponding servlet also has a doget() and dopost() methods in handling requests. After the servlet finishes processing the result, it will put the processed information in different scopes and return it to the web page for display.

If the foo function of the base class has a virtual keyword, then C++ will use a late-binding technique, i.e., it does not determine the specific calling function at compile time, but determines the calling function based on the type of object it actually points to at runtime.

The servlet acts as a controller in the MVC framework.

When we write an application, it is generally divided into a control layer, a business layer, and an entity layer.

In the BS mode, the servlet acts as the control layer, and its role is to hand over the data from the foreground to the business layer for processing, and then get the processed data from the business layer, and return the data to the frontend.

Regardless of the data format your server uses, the methods defined in the servlet model can only be request

response session, all of which are sent in the form of streams.

Directly bring it to the page through the request object, and then parse it. Parse it how you get it.

There are three ways to develop servlets:

1. Implement the servlet interface.

Servlets are not specifically designed to handle HTTP requests. Native servlet interface.

2. By inheriting the genericservlet

To write a servlet class directly by implementing the servlet interface, you need to implement the 5 methods defined in the servlet interface, in order to simplify the writing of the servlet, in the package, we are provided with an abstract class genericservlet, which provides a simple implementation of the other 4 methods except the service() method. The GenericServlet class defines a generic protocol-independent servlet

3. By inheriting httpservlet

Since most of the network applications, the browser accesses the server resources through the HTTP protocol, and the usually written servlets are mainly applied to the HTTP protocol requests and responses, in order to quickly develop the Servlet applied to the HTTP protocol, Sun provides us with an abstract class httpServlet in the package, which inherits from the GenericServlet class to create HTTP suitable for the Web site servlet。