在Java Servlet中，如何更改现有Cookie的值？ [英] In a Java Servlet how can I change the value of an existing cookie?

问题描述

在Java Servlet中，如何更改现有Cookie的值？在HttpServletResponse中有一个addCookie方法，但没有deleteCookie或editCookie

In a Java Servlet how can I change the value of an existing cookie? There is an addCookie method, but no deleteCookie or editCookie in HttpServletResponse

推荐答案

这些确实不存在。只需创建自己的实用程序方法即可。特别是得到所需的cookie是相当。肿。例如

Those indeed don't exist. Just create utility methods yourself which do that. Particularly getting the desired cookie is quite bloated. E.g.

public final class Servlets {

    private Servlets() {}

    public static Cookie getCookie(HttpServletRequest request, String name) {
        if (request.getCookies() != null) {
            for (Cookie cookie : request.getCookies()) {
                if (cookie.getName().equals(name)) {
                    return cookie;
                }
            }
        }

        return null;
    }

}

要编辑Cookie，然后将其添加到响应中：

To edit a cookie, set its value and then add it to the response:

Cookie cookie = Servlets.getCookie(request, "foo");

if (cookie != null) {
    cookie.setValue(newValue);
    response.addCookie(cookie);
}

如有必要，设置maxage，路径和域名，默认。

Set if necessary the maxage, path and domain as well if they differs from your default. The client namely doesn't send this information back.

要删除cookie，请将最大年龄设置为 0 （最好也是值 null ）：

To delete a cookie, set the max age to 0 (and preferably also the value to null):

Cookie cookie = Servlets.getCookie(request, "foo");

if (cookie != null) {
    cookie.setMaxAge(0);
    cookie.setValue(null);
    response.addCookie(cookie);
}

如果必要，设置路径和域，客户端不会返回此信息。

Set if necessary the path and domain as well if they differs from your default. The client namely doesn't send this information back.

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