Example 1: Java Program to Convert string to int using parseInt()
class Main {
public static void main(String[] args) {
// create string variables
String str1 = "23";
String str2 = "4566";
// convert string to int
// using parseInt()
int num1 = Integer.parseInt(str1);
int num2 = Integer.parseInt(str2);
// print int values
System.out.println(num1); // 23
System.out.println(num2); // 4566
}
}
In the above example, we have used the parseInt()
method of the Integer
class to convert the string variables into the int
.
Here, Integer
is a wrapper class in Java. To learn more, visit the Java Wrapper Class.
Note: The string variables should represent the int
values. Otherwise the compiler will throw an exception. For example,
class Main {
public static void main(String[] args) {
// create a string variable
String str1 = "Programiz";
// convert string to int
// using parseInt()
int num1 = Integer.parseInt(str1);
// print int values
System.out.println(num1); // throws NumberFormatException
}
}
Example 2: Java Program to Convert string to int using valueOf()
We can also convert the string variables into an object of Integer
using the valueOf()
method. For example,
class Main {
public static void main(String[] args) {
// create string variables
String str1 = "643";
String str2 = "1312";
// convert String to int
// using valueOf()
int num1 = Integer.valueOf(str1);
int num2 = Integer.valueOf(str2);
// print int values
System.out.println(num1); // 643
System.out.println(num2); // 1312
}
}
In the above example, the valueOf()
method of Integer
class converts the string variables into the int
.
Here, the valueOf()
method actually returns an object of the Integer
class. However, the object is automatically converted into the primitive type. This is called unboxing in Java. To learn more, visit Java autoboxing and unboxing.
That is,
// valueOf() returns object of Integer
// object is converted onto int
int num1 = Integer obj = Integer.valueOf(str1)