servlet学习

demo:http://pan.baidu.com/s/1nuTzMkT

package com.ws.study.servlet.huoquziyuan;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;

public class servlethuoqu2 extends HttpServlet {
	private int count;

	/**
	 * Constructor of the object.
	 */
	public servlethuoqu2() {
		super();
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		ServletContext srvcon=super.getServletContext();
		if("".equals(count)){
			
			count=1;
		}else{
			count++;
		}
		System.out.println(srvcon.getAttribute("username"));
		System.out.println("调用了"+count+"次");
		/*
		 * 用Classloader载入到WEB-INFclasses目录内然后获取
		 */
		
//		ClassLoader classl=this.getClass().getClassLoader();
//		InputStream input=classl.getResourceAsStream("a.txt");
//		System.out.println(IOUtils.toString(input));
		/*
		 * 用Class载入到当前类路径下 加斜杠载入到WEB-INFclasses下。
		 */
//		Class clas=this.getClass();
//		InputStream input=clas.getResourceAsStream("/../../index.jsp");
//		System.out.println(IOUtils.toString(input));
		
		/*
		 * 用servletContext获取文件内容
		 */
		InputStream input=srvcon.getResourceAsStream("/index.jsp");
		System.out.println(IOUtils.toString(input));
	//	System.out.println(srvcon.getResourcePaths("/"));
		
		
		response.setContentType("text/html");
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
		out.println("<HTML>");
		out.println("  <HEAD>" +
				"<meta http-equiv='Content-Type' content='text/html; charset=UTF-8'>" +
				"<TITLE>A Servlet</TITLE></HEAD>");
		out.println("  <BODY>");
		out.println("test 测试");
		out.print(this.getClass());
		out.println("  </BODY>");
		out.println("</HTML>");
		out.flush();
		out.close();
	}
	
	
	@Override
	public void init() throws ServletException {
		// TODO Auto-generated method stub
		System.out.println("我诞生了，我要setAttribute");
		super.getServletContext().setAttribute("username", "hackermi");
	}
	
	
	

}

package com.ws.study.servlet;

import java.io.IOException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class servletC extends servletAdd {

	@Override
	public void service(ServletRequest req, ServletResponse res)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("service调用了一次");
		this.getInitParameterNames();
	}

	@Override
	protected void init() {
		// TODO Auto-generated method stub
		System.out.println("servlet诞生了");
	}
	
	public void getInitParameterNames(){
		System.out.println("获取参数");
		enat=servletconfig.getInitParameterNames();
		while (enat.hasMoreElements()) {
			String canshu = (String) enat.nextElement();
			System.out.println(canshu);
		}
	}

	
	
	

}

package com.ws.study.servlet;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class servletAdd implements Servlet {

	public Enumeration<String> enat;
	protected ServletConfig servletconfig;
	public servletAdd() {
		// TODO Auto-generated constructor stub
	}

	@Override
	public void destroy() {
		// TODO Auto-generated method stub

	}

	@Override
	public ServletConfig getServletConfig() {
		// TODO Auto-generated method stub
		return this.servletconfig;
	}

	@Override
	public String getServletInfo() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void init(ServletConfig servletConfig) throws ServletException {
		// TODO Auto-generated method stub
		this.servletconfig=servletConfig;
		enat=servletConfig.getInitParameterNames();
		while (enat.hasMoreElements()) {
			String canshu = enat.nextElement();
			System.out.println(servletConfig.getInitParameter(canshu));
		}
		init();
	}

	@Override
	public void service(ServletRequest req, ServletResponse res)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("servletAdd被调用了一次");
		enat=servletconfig.getInitParameterNames();
		while (enat.hasMoreElements()) {
			String canshu = enat.nextElement();
			System.out.println(canshu);
		}
		
		System.out.println(this.getServletContext());
	}
	
	public ServletContext getServletContext(){
		return this.servletconfig.getServletContext();
	}
	

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}
	
	protected void init() {
		// TODO Auto-generated method stub

	}

}