!898 修复Gitee issue #I66CIR

Merge pull request !898 from Tom Xin/v5-dev-fix_#I66CIR

Author: looly

hutool-core/src/main/java/cn/hutool/core/net/url/UrlBuilder.java

@@ -108,9 +108,7 @@ public static UrlBuilder ofHttp(String httpUrl) {
 	 */
 	public static UrlBuilder ofHttp(String httpUrl, Charset charset) {
 		Assert.notBlank(httpUrl, "Http url must be not blank!");
-
-		final int sepIndex = httpUrl.indexOf("://");
-		if (sepIndex < 0) {
+		if (!httpUrl.startsWith("http://")&&!httpUrl.startsWith("https://")) {
 			httpUrl = "http://" + httpUrl.trim();
 		}
 		return of(httpUrl, charset);