问题原因：

在Java8及高版本以上的版本在源应用程序不信任目标应用程序的证书，因为在源应用程序的JVM信任库中找不到该证书或证书链。也就是目标站点启用了HTTPS 而缺少安全证书时出现的异常

解决方案：

我使用的是忽略证书验证

public class Base64Util {public static String getBase64FromUrl(String fileUrl) {InputStream inputStream = null;byte[] data = null;ByteArrayOutputStream swapStream = null;HttpsURLConnection conn = null;try {URL url = new URL(fileUrl);//判断当前文件url是否是httpsif (fileUrl.contains("https:")){//是https//绕过证书SSLContext context = createIgnoreVerifySSL();conn = (HttpsURLConnection) url.openConnection();conn.setSSLSocketFactory(context.getSocketFactory());inputStream = conn.getInputStream();}else {//当前链接是httpinputStream =  url.openConnection().getInputStream();}swapStream = new ByteArrayOutputStream();byte[] buff = new byte[100];int rc = 0;while ((rc = inputStream.read(buff, 0, 100)) > 0) {swapStream.write(buff, 0, rc);}data = swapStream.toByteArray();} catch (Exception e) {e.printStackTrace();} finally {IOUtils.closeQuietly(inputStream);IOUtils.closeQuietly(swapStream);}return new String(Base64.encodeBase64(data));}//绕过SSL、TLS证书public static SSLContext createIgnoreVerifySSL() throws NoSuchAlgorithmException, KeyManagementException {SSLContext sc = SSLContext.getInstance("TLS");// 实现一个X509TrustManager接口，用于绕过验证，不用修改里面的方法X509TrustManager trustManager = new X509TrustManager() {@Overridepublic void checkClientTrusted(java.security.cert.X509Certificate[] paramArrayOfX509Certificate,String paramString) throws CertificateException {}@Overridepublic void checkServerTrusted(java.security.cert.X509Certificate[] paramArrayOfX509Certificate,String paramString) throws CertificateException {}@Overridepublic java.security.cert.X509Certificate[] getAcceptedIssuers() {return null;}};sc.init(null, new TrustManager[]{trustManager}, null);return sc;}
}