fix bug

hutool-http/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>cn.hutool</groupId>
 		<artifactId>hutool-parent</artifactId>
-		<version>5.1.0</version>
+		<version>5.1.1-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>hutool-http</artifactId>

hutool-http/src/main/java/cn/hutool/http/HttpUtil.java

@@ -549,10 +549,13 @@ public class HttpUtil {
 		int pathEndPos = paramsStr.indexOf('?');
 		if (pathEndPos > -1) {
 			paramsStr = StrUtil.subSuf(paramsStr, pathEndPos + 1);
+			if (StrUtil.isBlank(paramsStr)) {
+				return Collections.emptyMap();
+			}
 		}
 
-		final Map<String, List<String>> params = new LinkedHashMap<>();
 		final int len = paramsStr.length();
+		final Map<String, List<String>> params = new LinkedHashMap<>();
 		String name = null;
 		int pos = 0; // 未处理字符开始位置
 		int i; // 未处理字符结束位置