Parse String into Integer value in Java

Tags: String Integer Convert Parse

In this Java core tutorial, we learn how to convert a String value into int value in Java application.

Using Integer.parseInt() static method

Following Java example using Integer.parseInt() static method to convert a String value into int value.

ParseStringToIntExample1.java 

public class ParseStringToIntExample1 {
    public static void main(String[] args) {
        int result1 = Integer.parseInt("1234");
        int result2 = Integer.parseInt("+5");
        int result3 = Integer.parseInt("-5");

        System.out.println(result1);
        System.out.println(result2);
        System.out.println(result3);
    }
}
The output is: 
1234
5
-5

The following example using Integer.parseInt() with String value in specified radix.

ParseStringToIntExample2.java 

public class ParseStringToIntExample2 {
    public static void main(String[] args) {
        int result1 = Integer.parseInt("123", 10);// radix 10
        int result2 = Integer.parseInt("1010", 2);// radix 2
        int result3 = Integer.parseInt("FFAA", 16);// radix 16

        System.out.println(result1);
        System.out.println(result2);
        System.out.println(result3);
    }
}
The output is: 
123
10
65450

The following example to parse a part of String value into int value.

ParseStringToIntExample3.java 

public class ParseStringToIntExample3 {
    public static void main(String[] args) {
        int beginIndex = 2;
        int endIndex = 4;
        int radix = 10;
        int result = Integer.parseInt("3456789", beginIndex, endIndex, radix);

        System.out.println(result);
    }
}
The output is: 
56

Using Integer.parseUnsignedInt() static method

Java also provides Integer.parseUnsignedInt() static method to parse String as unsigned integer value.

ParseStringToIntExample4.java 

public class ParseStringToIntExample4 {
    public static void main(String[] args) throws Exception {
        int result1 = Integer.parseUnsignedInt("1234");
        int result2 = Integer.parseUnsignedInt("+5");

        System.out.println(result1);
        System.out.println(result2);
    }
}
The output is: 
1234
5

ParseStringToIntExample5.java 

public class ParseStringToIntExample5 {
    public static void main(String[] args) {
        int result1 = Integer.parseUnsignedInt("123", 10);
        int result2 = Integer.parseUnsignedInt("1010", 2);
        int result3 = Integer.parseUnsignedInt("FFAA", 16);

        System.out.println(result1);
        System.out.println(result2);
        System.out.println(result3);
    }
}
The output is: 
123
10
65450

ParseStringToIntExample6.java 

public class ParseStringToIntExample6 {
    public static void main(String[] args) {
        int beginIndex = 2;
        int endIndex = 4;
        int radix = 10;
        int result = Integer.parseUnsignedInt("3456789", beginIndex, endIndex, radix);

        System.out.println(result);
    }
}
The output is: 
56

Happy Coding 😊

Check a String Is a Valid Integer in Java