servlet学习笔记（入门）

必须基于tomcat才能使用，单独的servlet无法启动。

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <!--对应tomcat的8.5.x版本，具体查看可以到tomcat.apache.org/whichversion.html中查看-->
            <version>3.1.0</version>
        </dependency>
    </dependencies>

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class servlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    /*
    使用IDE工具可以快速重写servlet的service方法
    通过对service方法的重写可以完成http的通信过程
    */
        super.service(req, resp);
    }
}

    <servlet>
        <servlet-name>这里是servlet的别名</servlet-name>
        <servlet-class>这里是servlet的完整路径</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>对应的servlet的别名</servlet-name>
        <url-pattern>以根目录为准的servlet的url路径</url-pattern>
    </servlet-mapping>

示例：

@WebServlet("/anno")
public class AnnotationServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().println("I'm annocation servlet !");
    }
}