第一種方式，實現Servlet接口

 1 package com.example.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.Servlet;
 6 import javax.servlet.ServletConfig;
 7 import javax.servlet.ServletException;
 8 import javax.servlet.ServletRequest;
 9 import javax.servlet.ServletResponse;
10 
11 public class
 
 testServlet1 implements Servlet {
12 
13     /**
14      * 銷毀方法
15      */
16     public void destroy() {
17         System.out.println("這是銷毀方法！");
18         
19     }
20     
21     /**
22      * 初始化方法
23      */
24     public void init(ServletConfig arg0) throws ServletException {
25         System.out.println("這是初始化方法！");
 
26     }
27 
28     /**
29      * 服務方法
30      */
31     public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
32         
33         System.out.println("這是服務方法！");
34         
35     }
36 
37     
38     //獲取servlet配置信息
39     public ServletConfig getServletConfig() {
 
40         
41         return null;
42     }
43 
44     //獲取servlet信息
45     public String getServletInfo() {
46         
47         return null;
48     }
49 }

第二種方式：繼承GenericServlet抽象類

GenericServlet抽象類中只有一個抽象方法service()方法

 1 package com.example.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.GenericServlet;
 6 import javax.servlet.ServletException;
 7 import javax.servlet.ServletRequest;
 8 import javax.servlet.ServletResponse;
 9 
10 public class testServlet2 extends GenericServlet{
11 
12     @Override
13     public void service(ServletRequest arg0, ServletResponse arg1) throws ServletException, IOException {
14         
15         System.out.println("這是服務方法！");
16     }
17 
18 }

第三種方式：繼承HttpServlet抽象類重寫doPut()和doPost()方法

 1 package com.example.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.http.HttpServlet;
 5 import javax.servlet.http.HttpServletRequest;
 6 import javax.servlet.http.HttpServletResponse;
 7 import java.io.IOException;
 8 
 9 public class testServlet3 extends HttpServlet{
10 
11     @Override
12     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
13 
14         System.out.println("這是get方法提交");
15         
16     }
17     
18 
19     @Override
20     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
21         System.out.println("這是post方法提交");
22     }
23 
24 }

web.xml配置文件如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <!-- sevlet配置 -->
    <!-- 1.servlet的定義：告訴容器如何來創建servlet -->
    <servlet>
        <servlet-name>test1</servlet-name>
        <servlet-class>com.example.servlet.testServlet1</servlet-class>
    </servlet>

    <!-- 2.配置servlet路徑 servlet映射 -->
    <!-- url-pattern 必須以/開頭 訪問：http://localhost:8080/servletPro/login  -->
    <servlet-mapping>
        <servlet-name>test1</servlet-name>
        <url-pattern>/login1</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>test2</servlet-name>
        <servlet-class>com.example.servlet.testServlet1</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>test2</servlet-name>
        <url-pattern>/login2</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>test3</servlet-name>
        <servlet-class>com.example.servlet.testServlet1</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>test3</servlet-name>
        <url-pattern>/login3</url-pattern>
    </servlet-mapping>
</web-app>

創建servlet的三種方式