PKIX path building failed的解决方法

某交易报如下错误：

javax.net.SSL.SSLHandshakeException: sun.security.validator.Validatorexception: PKIX path building failed:sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

解决方法如下：

1、原始cer证书下载

2、转换成jks格式证书，设置密码