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.
That is,
// valueOf() returns object of Integer
// object is converted onto int
int num1 = Integer obj = Integer.valueOf(str1)
To learn more, visit Java autoboxing and unboxing.