一.請列舉servlet接口中的方法,及其特點和作用;
簡述ServletContext接口的三個主要作用;
1.擷取web應用程式的初始化參數;
2.實作多個servlet對象共享資料;
3.讀取web應用下的資源檔案;
編寫一個servlet,實作統計網站被通路次數的功能;
package chapter03;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Test03
*/
public class Test03 extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Test03() {
super();
// TODO Auto-generated constructor stub
}
int count=0;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
count++;
response.setContentType("text/html;charset=utf-8");
response.getWriter().print("這是您第"+count+"次通路");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
編寫一段程式擷取servlet的配置資訊,從中擷取到參數名為encoding對應得參數值;
//需要在web.xml進行配置;
PrintWriter out = response.getWriter();
ServletConfig config = this.getServletConfig();
out.println("<h1>"+config.getInitParameter("encoding")+"</h1>");