常用的web服務(wù)器有： 1、IIS,出自微軟 2、Apache,linux，C語言寫的 3、tomcat是Apache項(xiàng)目中的一個(gè)，java寫的
servlet是服務(wù)器上運(yùn)行的程序其主要功能在于交互式地瀏覽和修改數(shù)據(jù)，生成動(dòng)態(tài)Web內(nèi)容。
先記錄下功能代碼吧，關(guān)于servlet的原理，等之后學(xué)習(xí)更深入了，再補(bǔ)充一下。
生命周期public class TestLiftCycleServlet extends HttpServlet { /** * 實(shí)例化 */ public TestLiftCycleServlet() { System.out.session-Cookie-"+i,"Cookie-Value_S"+i); resp.addCookie(cookie); cookie= new Cookie("Persistent-Cookie-"+i, " hello"); cookie.setMaxAge(3600);//時(shí)效性 resp.addCookie(cookie); } //設(shè)置網(wǎng)頁的字符編碼格式為gb2312 resp.setContentType("text/html;charset=gb2312"); PrintWriter pw = resp.getWriter(); //2 獲取cookie pw.println("獲取到cookie"); Cookie[] cookies = req.getCookies(); if(cookies!=null){ Cookie cookie = null; for(int i = 0; i < cookies.length; i++){ cookie= cookies[i]; pw.println("name:"+cookie.getName()+" value:"+cookie.getValue()); } } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("post"); doGet(req, resp); }}關(guān)于Session/** * * session是存在服務(wù)器端的，cookie是存在客戶端的。 * session可與瀏覽器關(guān)聯(lián)，每個(gè)窗口有獨(dú)一無二的sessionId.session就是服務(wù)端的一個(gè)內(nèi)存，能存儲(chǔ)任何內(nèi)容。鍵值對 * session是針對窗口的。不像cookie擁有路徑訪問問題，同一個(gè)application下的servlet/jsp可以共享一個(gè)session。需要同一個(gè)客戶端窗口 * * 如果瀏覽器支持cookie,創(chuàng)建session時(shí)會(huì)把sessionId保存在cookie里，保持不變。否則sessionId每次都說新生成的 * * session實(shí)現(xiàn)： cookie實(shí)現(xiàn)、url重寫實(shí)現(xiàn) * * * cookie(臨時(shí)的，寫在文件里)實(shí)現(xiàn)：sessionId存在臨時(shí)cookie里 * 使用url重寫的方式實(shí)現(xiàn)session，response。encodeURL()，轉(zhuǎn)碼，url后面添加sessionId * *http://blog.csdn.net/robbyo/article/details/17733743 */public class SessionDemo extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //獲取當(dāng)前的session,若無，就創(chuàng)建一個(gè)session HttpSession mySession = req.getSession(true); resp.setContentType("text/html"); PrintWriter out= resp.getWriter(); String heading; Integer accessCount = (Integer)mySession.getAttribute("accessCount"); if(accessCount==null){ accessCount = new Integer(0); heading="welcome,new comer"; }else{ heading="welcome back"; accessCount = new Integer(accessCount.intValue()+1); } mySession.setAttribute("accessCount", accessCount); out.println("<H3>show info saved in session</H3>"+accessCount); out.println("<H3>create Information</H3>"); out.println(" new Session:"+mySession.isNew()); out.println("session id:"+mySession.getId()+ ",create time:"+mySession.getCreationTime() //最近一次訪問的時(shí)間，session是有過期時(shí)間的 +",last access time:"+mySession.getLastAccessedTime()); out.println("<H3>Request Information</H3>"); out.println("Session ID from Request: " //上次使用的session + req.getRequestedSessionId()); out.println("<BR>Session ID via Cookie: " //方式1：通過cookie + req.isRequestedSessionIdFromCookie()); out.println("<BR>Session ID via rewritten URL: " //方式2：通過重寫url + req.isRequestedSessionIdFromURL()); out.println("<BR>Valid Session ID: " //session是否有效 + req.isRequestedSessionIdValid()); //添加了一個(gè)刷新,瀏覽器不使用cookie，就在url里面添加session out.println("<a href="+"SessionDemo"+">simple url </a>"); //經(jīng)測試，360不行，Chrome可以.response.encodeURL的功能是url后添加session。 String urlWithSession = resp.encodeURL("SessionDemo"); out.println("<a href='"+urlWithSession+"'>url with session</a>"); out.close(); // close output stream } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("post"); doGet(req, resp); }}application/** * application里面的值是共享的 * @author dell * */public class TestServletContext extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=gb2312"); PrintWriter out = resp.getWriter(); //獲取application ServletContext application = this.getServletContext(); //設(shè)置application里的內(nèi)容 Integer accessCount = (Integer)application.getAttribute("accessCount"); if(accessCount==null){ accessCount = new Integer(0); }else{ accessCount = new Integer(accessCount.intValue()+1); } application.setAttribute("accessCount", accessCount); //獲取application里的內(nèi)容 out.println("get count:"+accessCount); }}新聞熱點(diǎn)
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