How to use String indexof () in Java

There are four ways to find string substrings in Java (indexof ())

The IndexOf method returns an integer value that indicates the starting position of the substring in the string object. If no substring is found, 1 is returned.
If the startindex is negative, then startindex is treated as zero. If it is larger than the maximum character position index, it is treated as the largest possible index.

There are four ways to find string substrings in Java, as follows:
1, int indexOf (String str): Returns the index of the first occurrence of the specified substring in this string.
2, int indexOf (String str, int startIndex): Returns the index of the first occurrence of the specified substring in this string, starting at the specified index.
3, int lastIndexOf (string str): Returns the index of the specified substring that appears rightmost in this string.
4, int lastIndexOf (String str, int startIndex): Searches backward at the specified index, returning the index of the specified substring that last occurred in this string.

Example: Counts the number of occurrences of a specified string in the current string

 Public Static voidMain (string[] args) {String str="GHABCDEFGHFFGHFD"; intCount =0; //mode one, using regular expressions//Pattern pattern = pattern.compile ("gh"); //Matcher Matcher = Pattern.matcher (str); //While (Matcher.find ()) {//count++; // }                //mode Two, use the public int indexOf (String str) to return the specified sub-word//the index at which to first appear in this string. //Parameters://STR-Any string. //return://If the string argument appears as a substring in this object, the//The index of the first character of this seed string, if it does not act as a child//string appears, it returns-1.         intindex =0;  while(Index = Str.indexof ("GH", index))! =-1) {Index+="GH". Length (); Count++; } System. out. println (count); }

How to use String indexof () in Java