Servlet实现的三种方式

Servlet实现一共有三种方式：

 

Servlet --> GenericServlet --> HttpServlet 

Servlet是GenericServlet的父类

GenericServlet是HttpServlet的父类

 

1.实现 javax.servlet.Servlet接口

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public class mysevlet implements Servlet{       public void init(ServletConfig config) throws ServletException {         // TODO Auto-generated method stub               }       public ServletConfig getServletConfig() {         // TODO Auto-generated method stub         return null;     }       public void service(ServletRequest req, ServletResponse res)             throws ServletException, IOException {         // TODO Auto-generated method stub               }       public String getServletInfo() {         // TODO Auto-generated method stub         return null;     }       public void destroy() {         // TODO Auto-generated method stub               }       }

 

　2.继承GenericServlet类

   GenericServlet抽象类中只有一个抽象方法service()方法，适配器模式

public abstract class GenericServletextends java.lang.Objectimplements Servlet, ServletConfig, java.io.Serializable

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package com.zk.myservlet;   import java.io.IOException;   import javax.servlet.GenericServlet; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse;   public class myServlet extends GenericServlet{       @Override     public void init() throws ServletException {         // TODO Auto-generated method stub         super.init();         System.out.println("GenericServlet init...初始化");     }           @Override     public void service(ServletRequest arg0, ServletResponse arg1)             throws ServletException, IOException {         // TODO Auto-generated method stub         System.out.println("GenericServlet servlet demo2");     }       @Override     public void destroy() {         // TODO Auto-generated method stub         super.destroy();         System.out.println("GenericServlet destory...结束");     }       }

　　3.继承HttpServlet类

  public abstract class HttpServletextends GenericServletimplements java.io.Serializable

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public class myservlet2 extends HttpServlet{       int num=1;     //servlet->GenericServlet->HttpServlet     @Override     public void init() throws ServletException {         // TODO Auto-generated method stub         super.init();         System.out.println("HttpServlet...init...初始化");     }           @Override     public void service(ServletRequest arg0, ServletResponse arg1)             throws ServletException, IOException {         // TODO Auto-generated method stub         num++;         System.out.println(num);         System.out.println("HttpServlet...servlet demo2");     }       @Override     public void destroy() {         // TODO Auto-generated method stub         super.destroy();         System.out.println("HttpServlet...destory...结束");     }       @Override     protected void doGet(HttpServletRequest req, HttpServletResponse resp)             throws ServletException, IOException {         // TODO Auto-generated method stub         super.doGet(req, resp);                   System.out.println("********hello********");     }       @Override     protected void doPost(HttpServletRequest req, HttpServletResponse resp)             throws ServletException, IOException {         // TODO Auto-generated method stub         super.doPost(req, resp);         System.out.println("**********world*********");     }             }