cookie

创建cookie对象

Cookie newCookie= new Cookie(String key,Object value);

写入cookie对象

respone.addCookie(newCookie);

读取Cookie对象

Cookie[] cookies=request.getCookie();

案例—登录页面保存用户名和密码信息
login.jsp

<%
String username="";
String password="";
Cookie[] cookies=request.getCookie();
if(cookies!=null && cookies.length>0){
for(Cookie c:cookies){
if(c.getName().equals("username") ){
username=URLDecoder.decode(c.getValue());
}
if(c.getName.equals("password")){
password=URLDecoder.decode(c.getValue());
}
}
}
%>
<form name="loginForm" action="dologin.jsp" method="post">
<input type="text" name="username" value="<%=username %>"/>
<input type="password" name="password" value="<%=password %>"/>
<input type="checkbox" name="isUserCookie" checked="checked"/>
<input type="submit" name="submit" value="登录"/>
</form>

dologin.jsp

//导入java.net.*
<%
//首先判断用户是否选择了记录登录状态
String[] isUserCookies=request.getParamterValues("isUseCookie");
if(isUseCookies!=null && isUseCookies.length>0){
//把用户名和密码保存在Cookie对象中
String username=URLEncoder.encode(request.getParamter("username"));
String password=URLEncoder.encode(request.getParamter("password"));
Cookie usernameCookie=new Cookie("username");
Cookie passwordCookie=new Cookie("password");
usernameCookie.setMaxAge(864000);
passwordCookie.setMaxAge(860000);
response.addCookie(usernameCookie);
response.addCookie(passwordCookie);
}else{

Cookie[] cookies=request.getCookie();
if(cookies!=null && cookies.length>0){
for(Cookie c:cookies){
if(c.getName().equals("username") || c.getName.equals("password")){
c.setMaxAge(0);//设置cookie失效
response.addCookie(c);//重新保存cookies
}
}
}

}

%>
<a herf="user.jsp" target="_blank">查看用户名和密码</a>

user.jsp

<%
String username="";
String password="";
Cookie[] cookies=request.getCookie();
if(cookies!=null && cookies.length>0){
for(Cookie c:cookies){
if(c.getName().equals("username") ){
username=URLDecoder.decode(c.getValue());
}
if(c.getName.equals("password")){
password=URLDecoder.decode(c.getValue());
}
}
}
%>
用户名：<%=username %>
密码：<%= password %>