php: this & self

Use $this to refer to the current object. Use self to refer to the current class. In other words, use $this->member for non-static members, use self::$member for static members.

使用$this引用当前对象。使用self引用当前类。换句话说，非静态成员用$this->member，对于静态成员使用self::$member。