更新:尽管这个答案在几年前就已经被接受了，但请注意，Apache文档现在不建议使用这种方法。改用重定向。请看这个答案。

RewriteEngine On
RewriteCond %{HTTPS} !on
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

在.htaccess文件中使用以下代码自动将访问者重定向到站点的HTTPS版本:

RewriteEngine On

RewriteCond %{HTTPS} off

RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

如果你有一个现有的。htaccess文件:

不要重复“重写引擎”。

确保以RewriteCond和RewriteRule开头的行立即跟随已经存在的RewriteEngine On。

正如我在这个问题中所说的，我建议您避免盲目地将所有HTTP请求重定向到其HTTPS对等物，因为这可能会使您对安全性产生错误的印象。相反，您应该将HTTP站点的“根”重定向到HTTPS站点的根，并从那里链接到HTTPS。

问题是，如果HTTPS站点上的某些链接或表单使客户端向HTTP站点发送请求，那么在重定向之前，其内容将是可见的。

例如，如果一个通过HTTPS提供服务的页面有一个<form action="http://example.com/doSomething">的表单，并且发送了一些不应该明确发送的数据，浏览器将首先将完整的请求(包括实体，如果它是POST)首先发送到HTTP站点。重定向将立即发送到浏览器，由于大量用户禁用或忽略警告，它很可能被忽略。

Of course, the mistake of providing the links that should be to the HTTPS site but that end up being for the HTTP site may cause problems as soon as you get something listening on the HTTP port on the same IP address as your HTTPS site. However, I think keeping the two sites as a "mirror" only increases the chances of making mistakes, as you may tend to make the assumption that it will auto-correct itself by redirecting the user to HTTPS, whereas it's often too late. (There were similar discussions in this question.)

这将重定向所有的url到https和www

RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTPS_HOST} !^www.example.com$ [NC,OR]
RewriteCond %{HTTP_HOST} !^www.example.com$ [NC]
RewriteRule ^(.*)$ https://www.example.com/$1 [L,R=301]

经过多次尝试，考虑没有www和有www，这是可行的

RewriteEngine on
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} (www\.)?yourdomain.com
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

 Redirect 301 / https://example.com/

(当上面的答案都没用的时候，对我来说是有效的)

奖金:

ServerAlias www.example.com example.com

(固定https://www.example.com未找到)