📅 最后修改于: 2021-01-09 12:27:20 🧑 作者: Mango
Servlet接口提供了所有servlet的通用行为。Servlet接口定义了所有servlet必须实现的方法。
需要为创建任何Servlet(直接或间接)创建Servlet接口。它提供了3种生命周期方法，用于初始化servlet，服务请求和销毁servlet，以及2种非生命周期方法。
Servlet接口中有5种方法。初始化，服务和销毁是Servlet的生命周期方法。这些由Web容器调用。
| Method | Description |
|---|---|
| public void init(ServletConfig config) | initializes the servlet. It is the life cycle method of servlet and invoked by the web container only once. |
| public void service(ServletRequest request,ServletResponse response) | provides response for the incoming request. It is invoked at each request by the web container. |
| public void destroy() | is invoked only once and indicates that servlet is being destroyed. |
| public ServletConfig getServletConfig() | returns the object of ServletConfig. |
| public String getServletInfo() | returns information about servlet such as writer, copyright, version etc. |
通过实现servlet接口，让我们看一下servlet的简单示例。
import java.io.*;
import javax.servlet.*;
public class First implements Servlet{
ServletConfig config=null;
public void init(ServletConfig config){
this.config=config;
System.out.println("servlet is initialized");
}
public void service(ServletRequest req,ServletResponse res)
throws IOException,ServletException{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
out.print("");
out.print("hello simple servlet");
out.print("");
}
public void destroy(){System.out.println("servlet is destroyed");}
public ServletConfig getServletConfig(){return config;}
public String getServletInfo(){return "copyright 2007-1010";}
}