https://csr.chinassl.net/convert-ssl.html

通过连接，选择 perm  转 pfx  

输入密码 

下载证书 pfx 

配置到tomcat ，注意 tomcat8和tomcat9的配置方式不同

tomcat8:

<Connector port="443" protocol="HTTP/1.1"
    SSLEnabled="true"
    scheme="https"
    secure="true"
    keystoreFile="conf/3100375_www.wlkgzs.cn.pfx"
    keystoreType="PKCS12"
    keystorePass="X6kcS8y7"
    clientAuth="false"
    SSLProtocol="TLSv1+TLSv1.1+TLSv1.2"
    ciphers="TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA256,TLS_RSA_WITH_AES_256_CBC_SHA256" />
   

tomcat9:

 <Connector port="443" protocol="org.apache.coyote.http11.Http11NioProtocol"
               maxThreads="150" SSLEnabled="true">
        <SSLHostConfig>
            <Certificate certificateKeystoreFile="conf/xzybzx.org.cn.pfx"
            certificateKeystorePassword="xzybty"
                         certificateKeystoreType="PKCS12" />
        </SSLHostConfig>
    </Connector>