JAvaScriptは正規表現で文字列がファイルパスかどうかを判断します.

//js     。
var path = new RegExp("^[A-z]:\\\\(.+?\\\\)*$");
var isPath =  path.test("   ");
if (isPath){
    console.log("    : ",isPath);
}

//java     。 
// ^[A-z]:\\(.+?\\)*$
        boolean path =  "   1".matches("^[A-z]:\\\\(.+?\\\\)*$");

        boolean path1 =  "   2".matches("^[A-z]:\\\\(.+?\\\\)*$");

        boolean path2 =  "   3".matches("^[A-z]:\\\\(.+?\\\\)*$");