How to parse string into tokens in JAVA?

There is need of breaking strings into tokens from time to time for the JAVA programmers during the development.


                 

One such example is sending commands to server from console. So you may want to take whole command as String and then perform actions for that command by looking at the first word of string.

Suppose, you want to modify the port at which server is listening. So you pass the below command to server from console.

Command:
modify port 1200 to 1400

So to perform the actions for this command, you can fetch the first word of the string as token and then write your logic of modifying the port.

JAVA has class called StringTokenizer which allows to break string into tokens.

StringTokenizer methods does not differentiate between identifiers, numbers and quoted string.

You can also specify the delimiters during the creation of StringTokenizer or on a per token basis.

Usage:

String command = "modify port 1200 to 1400"
StringTokenizer sToken = new StringTokenizer(line);
while(sToken.hasMoreTokens()){
System.out.println(sToken.nextToken());
}

Output:

modify
port 
1200
to
1400.

Methods:

1. hasMoreTokens() : 

This methods checks if there are more tokens in the Tokenizer's string.

2. nextToken():

This method returns the next token in the string.

StringTokenizer can also be constructed using the string and delimiters. In this case the delimiter characters will not be count as Token.

String command = "modify port 1200 to 1400/1449"
StringTokenizer st = new StringTokenizer(command, "/");