How to Convert a String to Int in Java: Methods and Examples

There are many methods to convert a string to integer in Java. The method most commonly used is the pareseInt() method. There are multiple methods to convert string to an integer. In this article, we will have a look at all the possible methods to convert a String to int in Java

The three main methods are:

1. parseInt() method
2. valueOf() method
3. NumberFormatException method

parseInt() method to convert a String to Int in Java

In this method, the string is converted to a primitive int.

Syntax: int dtypename = Integer.parseInt(string);

Example: int res = Integer.parseInt(str);

Consider the code:

public class test {
                        public static void main(String args[])
                        {
                                    String str = "102";
                                    int res = Integer.parseInt(str);                                  
                                    System.out.println("the number is: "+ res);
                         }
}

OUTPUT:

EXPLANATION:

In the above code, we have a string variable “102”. We declare another variable res. This is of integer type. So the string variable is converted to an integer by using the parseInt() method.

valueOf() method: String to Int in Java

In this method, the string is converted to an Integer object.

Syntax: Integer dtypename = Integer.valueOf(string);

Example: Integer res = Integer.valueOf(str);

Consider the code:

public class test {
                        public static void main(String args[])
                        {
                                    String str = "102";
                                    int res = Integer.parseInt(str);                                  
                                    System.out.println("the number is: "+ res);
                         }
}

OUTPUT:

EXPLANATION:

In the above code, we have a string variable “122”. We declare another variable result as res. This is of integer type. So the string variable is converted to an integer by using the valueOf() method.

NOTE: parseInt() returns a primitive int whereas valueOf() returns a new Integer() object.

NumberFormatException Method

A NumberFormatException is thrown when the string is not parsable.

Consider the code:

public class test {
                        public static void main(String args[])
                        {
                                    String str = "102";
                                    int res = Integer.parseInt(str);                                  
                                    System.out.println("the number is: "+ res);
                         }
}

OUTPUT:

EXPLANATION:

An exception is generated when the string is not parsable.

With this, we come to an end of this String to Int in Java article. I hope you got an idea of all the three methods of Converting a String to int in Java.

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