说明：  Tomcat+keytool配置SSL，实现与网站建立https连接，浏览器与WEB SERVER之间要经过一个握手的过程来完成身份鉴定与密钥交换，建立安全连接。
(Tomcat+keytool configure SSL, to achieve the establishment https connection with the site, to go through a process to complete the handshake between the browser and the WEB SERVER identification and key exchange, establish a secure connection.)