一、cookie
1、设置cookie，内容为时间
Cookie cookie = new Cookie("LastAccessTime",System.currentTimeMillis()+"");
cookie.setMaxAge(1*30*24*3600);//设置有效期1个月
cookie.setPath("/项目名称");//访问整个项目都带cookie
2、获得cookie信息
Cookie cookies[] = request.getCookies();
for(int i = 0;cookie!=null&&i<cookies.length;i++){
if(cookies[i].getName().equals("LastAccessTime")){
long cookieValues = Long.parseLong(cookies[i].getVlues());//将String转化为10进制Long型
Date date = new Date(cookieValues);
response.getWrite().print(date);
}
}
二、session(getSession()——>session30分钟未使用)
1、设置session
HttpSession session = request.getSession();
session.setAttribute("name","哈哈哈哈");
2、得到session
HttpSession session = request.getSession();
//HttpSession session = request.getSession(false);//只获取不创建
String str = (String)session.getAttribute("name");
3、session配置,配置时间
<seeeion-config>
<session-timeout>20</session-timeout>
</session-config>
4、session摧毁
HttpSession session = request.getSession();
session.invalidate();
//session.removeAttribute("XXX");//移除某个session
5、使用地址重写方式获得session，只有在cookie禁用下会重写
request.getSession();
String url1 = response.encodingURL("需要重写的地址1");
String url2 = response.encodingURL("需要重写的地址2");
PrintWriter out = response.getWriter;
out.print("<a href = '"+url1+"'>XXXX</a>");
out.print("<a href = '"+url2+"'>YYYY</a>");
三、客户端表单提交问题
1、防止提交空密码
<form action="/项目/xxx" method ="post" onsubmit="return dosubmit(this)">
用户名:<input type="text" name="username"><br/>
密码:<input type="password" name = "password"><br/>
<input type="submit" value="提交">
</form>
<script>
function dosubmit(obj){
if(obj.category.value==''){
alter("请输入");
return false;
}
}
</script>
2、防止重复提交
<form action="/项目/xxx" method ="post" onsubmit="return dosubmit()">
用户名:<input type="text" name="username"><br/>
密码:<input type="password" name = "password"><br/>
<input type="submit" value="提交">
</form>
<script>
function dosubmit(){
var iscommitted = false;
if(!iscommitted){
iscommitted = true;
return true;
}else{
return false;
}
}
</script>