Javaweb做的bbs论坛

package bbs.tag; import java.io.IOException; import javax.servlet.ServletContext; import javax.servlet.ServletRequest; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.TagSupport; import hnkjxy.bbs.dao.DaoFactory; import hnkjxy.bbs.dao.UserDao; import hnkjxy.bbs.entity.*; /** * BBS头部信息呈现标签处理程序类 * @author William * */ public class HeaderTag extends TagSupport { //注册用户URL private String registerURL="reg.jsp"; //登录用户URL private String loginURL="login.jsp"; /* 标签结束处理程序。进行用户是否登录判别，以及显示登录信息的处理 * * @see javax.servlet.jsp.tagext.TagSupport#doEndTag() */ @Override public int doEndTag() throws JspException { //创建页面的输出流 JspWriter out = this.pageContext.getOut(); //取系统会话对象 HttpSession session = this.pageContext. getSession(); //获取上下文对象 ServletContext context = session.getServletContext(); //取在线人数值 Integer counter = (Integer)context. getAttribute("onlineUser"); //输出的缓存区 StringBuffer sb = new StringBuffer(); //输出页面Logo sb.append("<div> <img src='image/logo.gif'> </div> "); //从会话对象中取登录的用户信息 User user = (User)session.getAttribute("curUser"); //判断用户是否登录 if(null==user){ //判断Cookie中是否登录身份信息 //获取请求对象 ServletRequest request = this.pageContext.getRequest(); //取浏览器中的Cookie集合 Cookie[] cookies = ((HttpServletRequest)request).getCookies(); //遍历cookie查询用户身份信息 for(Cookie c :cookies){ //判断cookie中是否存在用户身份信息 if("curUser".equals(c.getName())){ //得到记住的用户编号 String uid = c.getValue(); //创建用户表访问接口 UserDao udao = DaoFactory.getUserDao(); //根据用户编号读取用户信息 user = udao.findUser(Integer.parseInt(uid)); //实现自动登录功能 session.setAttribute("curUser", user); break; } } } //在对Cookie扫描后仍然没有登录的处理 if(user==null){ //用户未登录的处理 sb.append("<DIV class=\"h\">"); String tmp= String.format("您尚未 <a href=\"%s\">登录</a> &nbsp;|", this.loginURL); sb.append(tmp); tmp = String.format("&nbsp; <A href=\"%s\">注册</A>|", this.registerURL); sb.append(tmp); //呈现在线用户人数 sb.append("在线用户人数：" + String.valueOf(counter)); sb.append("</div>"); }else{ //用户已登录处理 sb.append("<DIV class=\"h\">"); String tmp = String.format("%s，您好！ &nbsp;|", user.getUName()); sb.append(tmp); tmp = "&nbsp;<A href=\"LogoutServlet\">注销</A>|"; sb.append(tmp); //呈现在线用户人数 sb.append("在线用户人数：" + String.valueOf(counter)); sb.append("</div>"); } //输出到页面中 try { out.println(sb.toString()); out.flush(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return this.EVAL_PAGE; } /* * 标签开始时处理方法 * @see javax.servlet.jsp.tagext.TagSupport#doStartTag() */ @Override public int doStartTag() throws JspException { return this.SKIP_BODY; } public String getRegisterURL() { return registerURL; } public void setRegisterURL(String registerURL) { this.registerURL = registerURL; } public String getLoginURL() { return loginURL; } public void setLoginURL(String loginURL) { this.loginURL = loginURL; } }