In Java, you can use Integer.parseInt() to convert a String to int.

1. Integer.parseInt() Examples

Example to convert a String “10” to an primitive int.


	String number = "10";
	int result = Integer.parseInt(number);			
	System.out.println(result);

Output


10

2. Integer.valueOf() Examples

Alternatively, you can use Integer.valueOf(), it will returns an Integer object.


	String number = "10";
	Integer result = Integer.valueOf(number);		
	System.out.println(result);

Output


10
Note
In summary, parseInt(String) returns a primitive int, whereas valueOf(String) returns a new Integer() object.

3. NumberFormatException

If the string does not contain a parsable integer, a NumberFormatException will be thrown.


	String number = "10A";
	int result = Integer.parseInt(number);
	System.out.println(result);

Output


Exception in thread "main" java.lang.NumberFormatException: For input string: "10A"
	at java.lang.NumberFormatException.forInputString(Unknown Source)
	at java.lang.Integer.parseInt(Unknown Source)
	at java.lang.Integer.valueOf(Unknown Source)

References

  1. Integer.parseInt() JavaDoc
  2. Integer.valueOf() JavaDoc
  3. NumberFormatException JavaDoc