jsp 通过cookie 记住用户名-阿里云开发者社区

jsp 通过cookie 记住用户名

2016-05-10 2035

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简介：

Java Web中登录时如何记住用户名呢?

具体思路:

登录界面如下:

在后台(Servlet 或struts 的action)中进行判断,若登录成功则通过HttpServletResponse 添加一个cookie.

在登录的jsp页面中,通过request 获取cookie数组,然后遍历,若找到相应的cookie,则把cookie的value设置到表单的对应文本框中.

具体代码如下:

登录的JSP页面中(核心代码):

   Html代码  
    
  
<body>  
<%  
Cookie[] cookies = request.getCookies();  
String username33="";  
if (cookies != null) {  
    for (Cookie c : cookies) {  
        /*if ("password22".equals(c.getName())) {  
            user.setPassword(URLDecoder.decode(c.getValue(), "utf-8"));  
            continue;  
        }*/  
        if ("userEmail".equals(c.getName())) {  
            username33=URLDecoder.decode(c.getValue(), "utf-8");  
            break;  
        }  
    }  
}  
%>  
<script type="text/javascript">  
window.onload=function(){  
var username1='<%=username33 %>';  
//alert("username1:"+username1);  
if(username1){  
    if(username1!='' && username1!=null &&username1!=undefined){  
        document.getElementsByName("user.username")[0].value=username1;  
    }  
}  
}  
</script>  
...  
</body>  

后台的action:

   Java代码  
    
  
if (isLogin) {  
              
            //保存用户名(目前是邮箱)  
              
                String emaiCookieName = "userEmail";  
                HttpServletRequest request=ServletActionContext.getRequest();  
                Cookie[] cookies = request.getCookies();  
                boolean flag = false;  
                Cookie emailCook = null;  
                if (cookies != null)  
                {  
                    System.out.println("cookie 不为空");  
                    for (Cookie c : cookies)  
                    {  
  
                        if (emaiCookieName.equals(c.getName()))  
                        {  
                            System.out.println("找到了 "+emaiCookieName);  
                            System.out.println("cookie的值为 "+c.getValue());  
                            try {  
                                c.setValue(URLEncoder.encode(this.user.getUsername(), "utf-8"));  
                            } catch (UnsupportedEncodingException e) {  
                                e.printStackTrace();  
                            }  
                            emailCook = c;  
                            flag = true;  
                            break;  
                        }  
                    }  
                      
                }  
                if (!flag)  
                {  
                    System.out.println("没有找到 "+emaiCookieName);  
  
  
                    try {  
                        emailCook = new Cookie(emaiCookieName, URLEncoder.encode(  
                                this.user.getUsername(), "utf-8"));  
                    } catch (UnsupportedEncodingException e) {  
                        e.printStackTrace();  
                    }  
                }  
  
                    if (null != emailCook)  
                    {  
                         HttpServletResponse response=ServletActionContext.getResponse();  
                        if(!ValueWidget.isNullOrEmpty(issave) && issave.equalsIgnoreCase("save")){  
                            emailCook.setMaxAge(10000000);  
                             
                            response.addCookie(emailCook);  
                            System.out.println("保存cookie");  
                         }else{  
                                System.out.println("让 cookie 失效");  
                                emailCook.setMaxAge(0);  
                                response.addCookie(emailCook);  
                         }  
                    }  
  
                     
              
            return Action.SUCCESS;  
        }  