OpenSSL使用--转换pem为pfx证书
//用pem生成crt
1. openssl x509 -in test.pem -out test.crt
//生成pfx
2. openssl pkcs12 -export -out client.pfx -inkey test.key -in test.crt
//用pem生成crt
1. openssl x509 -in test.pem -out test.crt
//生成pfx
2. openssl pkcs12 -export -out client.pfx -inkey test.key -in test.crt