Java – How to split a string

To split a string, uses

String.split(regex)

. Review the following examples :

String phone = "012-3456789";
String[] output = phone.split("-");
System.out.println(output[0]);
System.out.println(output[1]);

Output

012
3456789

Note

This

split (regex)

takes a regex as an argument, remember to escape the regex special characters, like period/dot.

1. Split a Period / dot

The period / dot is a special character in regex, you have to escape it either with a double backlash

\\

. or uses the

Pattern.quote

method.

TestSplit.java

package com.mkyong.test

import java.util.regex.Pattern;

public class TestSplit {

public static void main(String[] args) {

String test = "abc.def.123";
String[] output = test.split("\\.");

//alternative
//String[] output = test.split(Pattern.quote("."));

System.out.println(output[0]);
System.out.println(output[1]);
System.out.println(output[2]);

}

}

Output

abc
def
123

Some common checking before split.

TestSplit.java

package com.mkyong.test

import java.util.regex.Pattern;

public class TestSplit {

public static void main(String[] args) {

String test = "abc.def.123";
if(test.contains(".")){
String[] output = test.split("\\.");
if(output.length!=3){
throw new IllegalArgumentException(test + " - invalid format!");
}else{
System.out.println(output[0]);
System.out.println(output[1]);
System.out.println(output[2]);
}
}else{
throw new IllegalArgumentException(test + " - invalid format!");
}

}

}

2.

StringTokenizer

example

In the old days, Java developers like to use the

StringTokenizer

class to split a string. This is because the

StringTokenizer

class is available since JDK 1.0 and the

String.split()

is available since JDK 1.4

TestSplit.java

package com.mkyong.test

import java.util.StringTokenizer;

public class TestSplit {

public static void main(String[] args) {

String test = "abc.def.123";

StringTokenizer token = new StringTokenizer(test, ".");

while (token.hasMoreTokens()) {
System.out.println(token.nextToken());
}

}

}

Output

abc
def
123

Note

This

StringTokenizer

is a legacy class, retained for compatibility reasons, the use is discouraged! Please use

string.split()

.