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Many times you get multiple values from the server or a web service and all the values are separated by a character or a pattern. Example, details of an employee received from a web server are 123@John@USA where the values separated by @ symbol are the id, Name and country of the employee respectively.
Now in order to display or get each of these values separately, you need some mechanism. That is where, split method becomes useful.

Also note that the regular expression can be a string of a single character or multiple characters.
split method types
java.lang.String class contains two overloaded versions of split method as explained below.
1. split(String pattern) : This method takes a string pattern as an argument and divides the source string based on that pattern. This method is the same as demonstrated above.
2. split(String pattern, int limit) : This method takes two arguments where the first argument is the string pattern based on which the string will be partitioned and second argument is an integer which determines the number of times, split operation will be applied on the source string.
Limit can have different range of values as follows
Positive: If the limit is greater than zero, then the split operation is applied for (limit – 1) times. Thus, in this case the length of result array will never be greater than the limit.
Zero: If the limit is zero, then the split operation will be applied as long as the pattern is present in the source string.
When the limit is zero, then the trailing empty strings will be removed from the result array. This is the same as the single argument split method.
Negative: When the limit is less than zero, then the split operation will be applied as long as the pattern is present in the source string as in the previous option but here trailing empty strings will also be present in the resultant array.

Since the dot is a special character in regular expression, it is required to escape this character, that is why it is preceded with double back slashes(\\).

public class SplitDemo {
   public static void main(String[] args) {
	// source string
	String str = "Hi!there!Welcome!to!Java";
	// split the string on a pattern and assign result to array
	String[] arr = str.split("!");
	// iterate over the array
	for (String item : arr) {
	   // print the string
	   System.out.println(item);
	}
   }
}

Above code when executed prints the below output

Output should be self-explanatory by now.

split string by space example
There are two ways to split a string with a space as pattern.
1. Provide a space(” “) as the pattern to the split method.
2. Supply regular expression equivalent to a space which is \\s as the pattern to split method.
Both the approaches are demonstrated below.

public class SplitSpaceDemo {
   public static void main(String[] args) {
	// source string
	String str = "Hi there Welcome";
	// split the string on space
	String[] arr = str.split(" ");
	// iterate over the array
	for (String item : arr) {
	   // print the string
	   System.out.println(item);
	}
        // split the string on regular expression
	[] arr = str.split("\\s");
	// iterate over the array
	for (String item : arr) {
	   // print the string
	   System.out.println(item);
	}
   }
}

Above program produces below output

Hope this article must have clarified the concept of split method in java.lang.String class and its usage. Hit the clap below if you liked the post.