Write a Java program to convert string to int or integer. In this Java programming language, we can use parseInt and valueOf methods to convert a string to an integer or int. In this example, we use the parseInt method.
package NumPrograms; public class StringToInt1 { public static void main(String[] args) { String s1 = "2020"; String s2 = "10"; int x = Integer.parseInt(s1); int y = Integer.parseInt(s2); System.out.println(x); System.out.println(y); } }

Java Program to Convert String to Int
Let me perform the addition before and after converting the string to an integer.
package NumPrograms; public class StringToInt2 { public static void main(String[] args) { String s1 = "1040"; int x = Integer.parseInt(s1); System.out.println(s1 + 50); System.out.println(x + 50); } }
104050
1090
This Java example uses the valueOf method to convert the string to an integer.
package NumPrograms; public class StringToInt3 { public static void main(String[] args) { String s1 = "2000"; int x = Integer.valueOf(s1); System.out.println(x); System.out.println(s1 + 150); System.out.println(x + 150); } }
2000
2000150
2150
Let us try to convert the string text to an integer using parseInt. It will throw the exception.
package NumPrograms; public class StringToInt4 { public static void main(String[] args) { String s1 = "tutorialgateway"; int x = Integer.parseInt(s1); System.out.println(x); } }
Exception in thread "main" java.lang.NumberFormatException: For input string: "tutorialgateway"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at NumPrograms.StringToInt4.main(StringToInt4.java:9)
Trying to convert string text to int using the valueOf, and the program throws the error.
package NumPrograms; public class StringToInt5 { public static void main(String[] args) { String s1 = "Java Programs"; int x = Integer.valueOf(s1); System.out.println(x); } }
Exception in thread "main" java.lang.NumberFormatException: For input string: "Java Programs"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.valueOf(Integer.java:766)
at NumPrograms.StringToInt5.main(StringToInt5.java:9)
This Java example accepts the user input string value and converts it to an integer using valueOf and parseInt functions.
package NumPrograms; import java.util.Scanner; public class StringToInt6 { private static Scanner sc; public static void main(String[] args) { String s1; sc= new Scanner(System.in); System.out.print("Please Enter any Text = "); s1 = sc.nextLine(); int x = Integer.valueOf(s1); System.out.println("valueOf(s1) result = " + x); int y = Integer.parseInt(s1); System.out.println("parseInt(s1) result = " + y); } }
Please Enter any Text = 13476
valueOf(s1) result = 13476
parseInt(s1) result = 13476