301: permanent redirect: the URL is old and should be replaced. Browsers will cache this. Example usage: URL moved from /register-form.html to signup-form.html. The method will change to GET, as per RFC 7231: "For historical reasons, a user agent MAY change the request method from POST to GET for the subsequent request." 302: temporary redirect. Only use for HTTP/1.0 clients. This status code should not change the method, but browsers did it anyway. The RFC says: "Many pre-HTTP/1.1 user agents do not understand [303]. When interoperability with such clients is a concern, the 302 status code may be used instead, since most user agents react to a 302 response as described here for 303." Of course, some clients may implement it according to the spec, so if interoperability with such ancient clients is not a real concern, 303 is better for consistent results. 303: temporary redirect, changing the method to GET. Example usage: if the browser sent POST to /register.php, then now load (GET) /success.html. 307: temporary redirect, repeating the request identically. Example usage: if the browser sent a POST to /register.php, then this tells it to redo the POST at /signup.php. 308: permanent redirect, repeating the request identically. Where 307 is the "no method change" counterpart of 303, this 308 status is the "no method change" counterpart of 301.

RFC 7231(从2014年开始)可读性很强，不会过于冗长。如果你想知道确切的答案，这本书是推荐阅读的。其他一些答案使用了1999年的RFC 2616，但没有任何变化。

RFC 7238指定308状态。它被认为是实验性的，但在2016年已经被所有主要浏览器支持。

另外，对于服务器管理员，重要的是要注意，如果使用307重定向，浏览器可能会向用户显示提示。

例如，Firefox和Opera会要求用户允许重定向，而Chrome、IE和Safari会透明地进行重定向。

*每个防弹SSL和TLS(第192页)。

区别在于重定向POST, PUT和DELETE请求，以及服务器对用户代理行为的期望(RFC 2616):

注意:RFC 1945和RFC 2068指定不允许客户端这样做 更改重定向上的方法 请求。然而，大多数现有用户 代理实现将302视为 这是303响应，执行一个 GET Location字段值 不管最初的请求是什么 方法。状态代码是303和307 已添加的服务器，希望 明确地说明是哪一种 的反应是预期的 客户端。

另外，请阅读维基百科关于30x重定向代码的文章。

302的预期:重定向使用相同的请求方法POST在NEW_URL

CLIENT POST OLD_URL -> SERVER 302 NEW_URL -> CLIENT POST NEW_URL

实际302,303:重定向改变请求方法从POST到GET的NEW_URL

CLIENT POST OLD_URL -> SERVER 302 NEW_URL -> CLIENT GET NEW_URL (redirect uses GET)
CLIENT POST OLD_URL -> SERVER 303 NEW_URL -> CLIENT GET NEW_URL (redirect uses GET)

307的ACTUAL:重定向在NEW_URL上使用相同的请求方法POST

CLIENT POST OLD_URL -> SERVER 307 NEW_URL -> CLIENT POST NEW_URL

307的出现是因为用户代理采用了一种事实上的行为，即接收到302响应的POST请求并向Location响应头发送GET请求。

这是不正确的行为——只有303才会导致POST转换为GET。如果最初的POST请求返回302，用户代理在请求新URL时应该(但不)坚持使用POST方法。

引入307是为了允许服务器向用户代理清楚地表明，当客户端遵循Location响应报头时，不应该对方法进行更改。

302 is temporary redirect, which is generated by the server whereas 307 is internal redirect response generated by the browser. Internal redirect means that redirect is done automatically by browser internally, basically the browser alters the entered url from http to https in get request by itself before making the request so request for unsecured connection is never made to the internet. Whether browser will alter the url to https or not depends upon the hsts preload list that comes preinstalled with the browser. You can also add any site which support https to the list by entering the domain in the hsts preload list of your own browser which is at chrome://net-internals/#hsts.One more thing website domains can be added by their owners to preload list by filling up the form at https://hstspreload.org/ so that it comes preinstalled in browsers for every user even though I mention you can do particularly for yourself also.

Let me explain with an example: I made a get request to http://www.pentesteracademy.com which supports only https and I don't have that domain in my hsts preload list on my browser as site owner has not registered for it to come with preinstalled hsts preload list. GET request for unsecure version of the site is redirected to secure version(see http header named location for that in response in above image). Now I add the site to my own browser preload list by adding its domain in Add hsts domain form at chrome://net-internals/#hsts, which modifies my personal preload list on my chrome browser.Be sure to select include subdomains for STS option there. Let's see the request and response for the same website now after adding it to hsts preload list. you can see the internal redirect 307 there in response headers, actually this response is generated by your browser not by server. Also HSTS preload list can help prevent users reach the unsecure version of site as 302 redirect are prone to mitm attacks. Hope I somewhat helped you understand more about redirects.