第三章课后练习题

一.请列举servlet接口中的方法，及其特点和作用；

简述ServletContext接口的三个主要作用；

1.获取web应用程序的初始化参数；

2.实现多个servlet对象共享数据；

3.读取web应用下的资源文件；

编写一个servlet,实现统计网站被访问次数的功能；

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("这是您第"+count+"次访问");
	}

	/**
	 * @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);
	}

}
           

编写一段程序获取servlet的配置信息，从中获取到参数名为encoding对应得参数值；

//需要在web.xml进行配置；
PrintWriter out = response.getWriter();
		ServletConfig config = this.getServletConfig();
		out.println("<h1>"+config.getInitParameter("encoding")+"</h1>");