请问java如何用cookies保存用户登录信息？

Question

java如何用cookies保存用户登录信息

Answer 1

一．本程序要实现的功能第一次登录页面时，若在表单中选择了“记住密码”，则下次登录网站时不用在填写表单，这里用“success.jsp”表示要打开的页面。若本地Cookie文件中已经保存了验证信息，则会显示已登录，否则会显示没登录。具体如下所示：① .填写表单，选择记住密码“一天“，代码文件为：login.jsp② .按下提交后，客户锻页面跳到check.jsp，实际上在服务端已经跳到了“success.jsp”页面。③ .新打开一个浏览器，然后直接打开“success.jsp”页面，此时提示已登录。说明Cookie起到了自动登录的作用。若第①步中，在记住密码项中选择“不保存”则登录“success.jsp”页面二. 对应代码login.jsp[java] view plaincopy<%@ page contentType="text/html;charset=GBK"%><mce:script language="javaScript"><!--function validate(f){if(!(/^/w{5,15}$/.test(f.userId.value))){alert("用户id必须为5-15位！");f.userId.focus();return false;}if(!(/^/w{5,15}$/.test(f.password.value))){alert("密码必须为5-15位！");f.password.focus();return false;}return true;}// --></mce:script><form action="check.jsp" method="post" onSubmit="return validate(this)"><table border="0"><tr><td>登录程序</td></tr><tr><td>用户id:</td><td><input type="text" name="userid"></td></tr><tr><td>密 码:</td><td><input type="password" name="password"></td></tr><tr><td>记住密码？</td><td><select name="savetime"><option value="0" selected>不保存</option><option value=<%=24*60*60%>>一天</option><option value=<%=24*60*60*7%>>一周</option></select></td></tr><tr><td> <input type="submit" value="确认"></td><td> <input type="reset" value="重置"></td></tr></table></form>check.jsp[c-sharp] view plaincopy<%@ page import="java.sql.*"%><%!public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;public static final String DBURL = "jdbc:mysql://localhost:3306/jspDemo" ;public static final String DBUSER = "root" ;public static final String DBPASS = "root" ;%><%Connection conn = null ;PreparedStatement pstmt = null ;ResultSet rs = null ;boolean flag = false ; // 表示登陆成功或失败的标记%><%String userid = request.getParameter("userid") ; // 接收表单参数String password = request.getParameter("password") ; // 接收表单参数String savetime=request.getParameter("savetime");System.out.println(savetime);try{Class.forName(DBDRIVER) ;conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;String sql = "SELECT id FROM tuser WHERE id=? AND password=?" ;pstmt = conn.prepareStatement(sql) ;pstmt.setString(1,userid) ;pstmt.setString(2,password) ;rs = pstmt.executeQuery() ;if(rs.next()){// 如果有内容，则此处执行，表示查询出来，合法用户flag = true ;session.setAttribute("userid",userid);//将验证信息保存到CookieCookie cid=new Cookie("userid",userid);Cookie cpass=new Cookie("password",password);cid.setMaxAge(Integer.parseInt(savetime));cpass.setMaxAge(Integer.parseInt(savetime));response.addCookie(cid);response.addCookie(cpass);}}catch(Exception e){}finally{try{conn.close() ; // 连接一关闭，所有的操作都将关闭}catch(Exception e){e.printStackTrace();}}%><%if(flag){ // 登陆成功，应该跳转到success.jsp%><jsp:forward page="success.jsp"/><%}else{ // 登陆失败，跳转到failure.jsp%><jsp:forward page="failure.jsp"/><%}%>CookieCheck.jsp[java] view plaincopy<%@ page contentType="text/html;charset=GBK"%><%@ page import="java.sql.*"%><%!public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;public static final String DBURL = "jdbc:mysql://localhost:3306/jspDemo" ;public static final String DBUSER = "root" ;public static final String DBPASS = "root" ;%><%Connection conn = null ;PreparedStatement pstmt = null ;ResultSet rs = null ;boolean flag = false ; // 表示登陆成功或失败的标记%><%if(session.getAttribute("userid")==null){Cookie[] c=request.getCookies();String userid=null;String password=null;if(c!=null){for(int i=0;i<c.length;i++){if("userid".equals(c[i].getName())){userid = c[i].getValue() ; // 接收Cookie信息}if("password".equals(c[i].getName())){password = c[i].getValue() ; // 接收Cookie信息}}if(userid!=null&&password!=null){try{Class.forName(DBDRIVER) ;conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;String sql = "SELECT id FROM tuser WHERE id=? AND password=?" ;pstmt = conn.prepareStatement(sql) ;pstmt.setString(1,userid) ;pstmt.setString(2,password) ;rs = pstmt.executeQuery() ;if(rs.next()){// 如果有内容，则此处执行，表示查询出来，合法用户flag = true ;session.setAttribute("userid",userid);}}catch(Exception e){}finally{try{conn.close() ; // 连接一关闭，所有的操作都将关闭}catch(Exception e){e.printStackTrace();}}}}}%>succss.jsp[java] view plaincopy<%@ page contentType="text/html;charset=GBK"%><jsp:include page="CookieCheck.jsp"/><%if(session.getAttribute("userid")!=null){%><h1>登陆成功，欢迎光临！</h1><%}else{%><h1> 您还未登录！</h1><%}%>failue.jsp[xhtml] view plaincopy<%@ page contentType="text/html;charset=GBK"%><h1>登陆失败，请重新<a href="login.html" mce_href="login.html">登陆</a></h1>