Life cycle of Servlet

Servlet Life cycle

1、 load -web.xml

<!--  Statement Servlet -->
  <servlet>
  	<!-- servlet Another name for  -->
  	<servlet-name>first</servlet-name>
  	<!--  Sensitive information , Need alias  -->
  	<servlet-class>com.imooc.servlet.FirstServlet</servlet-class>
  </servlet>
  
  <!--  take Servlet And URL binding  -->
  <servlet-mapping>
  	<servlet-name>first</servlet-name>
  	<url-pattern>/hi</url-pattern>
  </servlet-mapping>

load web.xml Will not create FirstServlet object

2、 establish - Constructors

public FirstServlet() {
    
		System.out.println(" Creating FirstServlet object ");
	}

3、 initialization -init()

public void init(ServletConfig config) throws ServletException {
    
		System.out.println(" Initializing FirstServlet object ");
	}

4、 Provide services -service()

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
		// TODO Auto-generated method stub
		//  Receive the parameters sent by the request 
		String name = request.getParameter("name");
		String html = "<h1 style='color:red'>hi," + name + "!</h1><hr/>";
		System.out.println(" The response data returned to the browser is ：" + html);
		PrintWriter out = response.getWriter();
		out.println(html);// take html Send it back to the browser 
	}

• On a visit service() Method FirstServlet object
  
• Multiple access , There is only one in the global FirstServlet object
  

5、 The destruction -destory()

public void destroy() {
    
		System.out.println(" It's being destroyed FirstServlet object ");
	}

• The code will be destroyed after adjustment FirstServlet object , Only when you visit again FirstServlet object