创建servlet的三种方式

第一种方式，实现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      * 销毁方法
15      */
16     public void destroy() {
17         System.out.println("这是销毁方法！");
18         
19     }
20     
21     /**
22      * 初始化方法
23      */
24     public void init(ServletConfig arg0) throws ServletException {
25         System.out.println("这是初始化方法！");
26     }
27 
28     /**
29      * 服务方法
30      */
31     public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
32         
33         System.out.println("这是服务方法！");
34         
35     }
36 
37     
38     //获取servlet配置信息
39     public ServletConfig getServletConfig() {
40         
41         return null;
42     }
43 
44     //获取servlet信息
45     public String getServletInfo() {
46         
47         return null;
48     }
49 }

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第二种方式：继承GenericServlet抽象类

GenericServlet抽象类中只有一个抽象方法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("这是服务方法！");
16     }
17 
18 }

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第三种方式：继承HttpServlet抽象类重写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("这是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("这是post方法提交");
22     }
23 
24 }

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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的定义：告诉容器如何来创建servlet -->
    <servlet>
        <servlet-name>test1</servlet-name>
        <servlet-class>com.example.servlet.testServlet1</servlet-class>
    </servlet>

    <!-- 2.配置servlet路径 servlet映射 -->
    <!-- url-pattern 必须以/开头 访问：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>

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