Programa Java para convertir una string a int

En Java, mientras operamos con strings, hay momentos en los que necesitamos convertir un número representado como una string en un tipo entero. Por lo general, hacemos esto porque podemos operar con un conjunto amplio y flexible de operaciones sobre strings. El método generalmente utilizado para convertir String a Integer en Java es parseInt() de la clase String .

Variantes del método parseInt() 

Existen dos variantes de este método:

// Java program to demonstrate working parseInt()
// Where No NumberFormatException is Thrown
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
        // Custom wide-varied inputs to illustrate
        // usage of valueOf() method
        int decimalExample = Integer.parseInt("20");
        int signedPositiveExample = Integer.parseInt("+20");
        int signedNegativeExample = Integer.parseInt("-20");
        int radixExample = Integer.parseInt("20", 16);
        int stringExample = Integer.parseInt("geeks", 29);
 
        // Print commands on console
        System.out.println(decimalExample);
        System.out.println(signedPositiveExample);
        System.out.println(signedNegativeExample);
        System.out.println(radixExample);
        System.out.println(stringExample);
    }
}

// Java Program to Demonstrate Working of parseInt() Method
// Where NumberFormatException is Thrown
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
        // Custom wide-varied inputs to illustrate
        // usage of valueOf() method
        int decimalExample = Integer.parseInt("20");
        int signedPositiveExample = Integer.parseInt("+20");
        int signedNegativeExample = Integer.parseInt("-20");
        int radixExample = Integer.parseInt("20", 16);
        int stringExample = Integer.parseInt("geeks", 29);
 
        // It will raise NumberFormatException
        String invalidArguments = "";
        int emptyString
            = Integer.parseInt(invalidArguments);
        int outOfRangeOfInteger
            = Integer.parseInt("geeksforgeeks", 29);
        int domainOfNumberSystem
            = Integer.parseInt("geeks", 28);
 
        // Print commands on console
        System.out.println(decimalExample);
        System.out.println(signedPositiveExample);
        System.out.println(signedNegativeExample);
        System.out.println(radixExample);
        System.out.println(stringExample);
    }
}

// Java Program to Demonstrate Working of valueOf() Method
 
// Main class
public class GFG {
   
    // Main driver method 
    public static void main(String args[])
    {
        // Custom wide-varied inputs to illustrate
        // usage of valueOf() method
        int decimalExample = Integer.valueOf("20");
        int signedPositiveExample = Integer.valueOf("+20");
        int signedNegativeExample = Integer.valueOf("-20");
        int radixExample = Integer.valueOf("20", 16);
        int stringExample = Integer.valueOf("geeks", 29);
 
        // Print statements
        System.out.println(decimalExample);
        System.out.println(signedPositiveExample);
        System.out.println(signedNegativeExample);
        System.out.println(radixExample);
        System.out.println(stringExample);
    }
}