跨域访问 - cookies

最新推荐文章于 2024-11-07 22:09:46 发布

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最新推荐文章于 2024-11-07 22:09:46 发布

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文章标签： javascript python java ViewUI

原文链接：https://my.oschina.net/thinwonton/blog/1036793

2019独角兽企业重金招聘Python工程师标准>>>

跨域写入cookie

可以通过URL参数实现跨域cookie写入，例如，www.a.com域需要为www.b.com域写入cookie信息，token=abcd。

输入图片说明

清单：实现重定向，URL： http://www.a.com/token?from=http://www.b.com/set_cookie

@WebServlet("/token")
public class TokenGeneratorServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 生成token
        String token = "abcd";

        String cookieName = "token";
        String cookieVal = token;

        //写入本域cookie
       //Cookie cookie = new Cookie(cookieName, cookieVal);
        //cookie.setPath("/");
        //response.addCookie(cookie);

        // 请求的原始来源域
        String from = request.getParameter("from");

        response.sendRedirect(from + "?cname=" + cookieName + "&cval=" + cookieVal); //重定向到目标域
    }

}

清单：实现写入cookie，URL：http://www.b.com/set_cookie

@WebServlet("/set_cookie")
public class SetCookieServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response) throws ServletException, IOException {
        
        // 将要写入的cookie项，调用者通过参数传递
        String cookieName = request.getParameter("cname");  //cookie的key
        String cookieVal = request.getParameter("cval");  //cookie的value

        // 生成cookie
        Cookie cookie = new Cookie(cookieName, cookieVal);
        cookie.setPath("/");
        response.addCookie(cookie);
    }

}

缺点：只能实现向一个域写入cookie

跨域读取cookie

可以通过js的script标签读取其它域的cookie。

假设页面cookie_reader.jsp 需要读取www.b.com的cookie值token，现在www.b.com域名的网站对外暴露了 URL为http://www.b.com/read_cookies的API，该API将读取该域所有的cookie键值对，然后把键值对以下面这种形式，返回。

var cookie_key1=cookie_value1; var cookie_key2=cookie_value2

清单：cookie_reader.jsp 读取cookie值：token，并弹窗

<%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>读取其它域cookie信息</title>

    <!--
        通过script标签执行另一个域实现的读取cookie的方法，
        script标签返回结果将是变量定义形式的js代码，其中每一个变量表示一个cookie项
        这些代码加载后，此页面后续js代码可直接读取已定义的变量值，即各cookie值
     -->
    <script type="text/javascript" src="http://www.b.com/read_cookies"></script>

</head>
<body>

<script type="text/javascript">
    alert(token);
</script>
</body>
</html>

清单：read_cookies API接口

@WebServlet("/read_cookies")
public class ReadCookiesServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response) throws ServletException, IOException {

        Cookie[] cookies = request.getCookies();
        StringBuilder builder = new StringBuilder();

        // 一定要正确设置响应类型，否则可能导致IE不解析js而直接进行下载操作
        response.setContentType("application/javascript");

        if (cookies != null) {
            PrintWriter writer = response.getWriter();
            for (Cookie cookie : cookies) {
                builder.setLength(0);
                // 结果类似于var token='test123';
                builder.append("var ")
                        .append(cookie.getName())
                        .append("=")
                        .append("'")
                        .append(cookie.getValue())
                        .append("'")
                        .append(";");
                writer.write(builder.toString());
            }
        }
    }
}

转载于:https://my.oschina.net/thinwonton/blog/1036793