De parseDouble-methode van de Java Double-klasse retourneert een nieuwe dubbele waarde die wordt geïnitialiseerd op de waarde die overeenkomt met de gedefinieerde String.

Deze methode voert hetzelfde uit als de methode valueOf() van de klasse Float.

Syntaxis

 public static double parseDouble(String s) throws NumberFormatException 

Parameters

S- Dit is de string die moet worden geparseerd.

Winstwaarde

De methode parseDouble() retourneert de dubbele waarde die overeenkomt met de doorgegeven parameter.

Gooit

De parseDouble() methode genereert:

1. NullPointerException- als de doorgegeven string nul is.

2. GetalFormatUitzondering- als de doorgegeven string geen parseerbare float bevat.

voorbeeld 1

 public class Double_parseDoubleMethodExample1 { public static void main(String[] args) { String val1='1000'; String val2='156'; //here instead of adding it will concatenate two Strings //but will convert the String into Float Double d = Double.parseDouble(val1+val2); System.out.println('1. Sum ='+d); Double f1 = Double.parseDouble(val1)+Double.parseDouble(val2); System.out.println('2. Sum ='+f1); Double f2 = Double.parseDouble(val1)*Double.parseDouble(val2); System.out.println('3. Multiplication ='+f2); Double f3 = Double.parseDouble(val1)/Double.parseDouble(val2); System.out.println('4. Division ='+f3); Double f4 = Double.parseDouble(val1)%Double.parseDouble(val2); System.out.println('5. Reminder ='+f4); } } 

Uitgang:

 1. Sum =1000156.0 2. Sum =1156.0 3. Multiplication =156000.0 4. Division =6.410256410256411 5. Reminder =64.0 

Voorbeeld 2

 import java.util.Scanner; public class Double_parseDoubleMethodExample2 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print(&apos;Enter your age:&apos;); String str = scanner.next(); // Double d1 = Double.parseDouble(str); Double d2 = 2018 - d1 ; System.out.println(&apos;Your year of birth is = &apos;+d2); if(d2<1965){ system.out.println('you are an adult, you eligible for the discount in railway tickets.'); } else{ double d3="d2-1965;" system.err.println('sorry! not eligible.try again after '+d3+' years'); < pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Enter your age:09 Sorry! You are not eligible.Try again after 44.0 years Your year of birth is = 2009.0 </pre> <h2>Example 3</h2> <pre> import java.util.Scanner; public class Double_parseDoubleMethodExample3 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print(&apos;Enter any string:&apos;); String str = scanner.next(); Double d1= Double.parseDouble(str); System.out.println(&apos;Double value = &apos;+ d1); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Enter any string:Himanshu@123 Exception in thread &apos;main&apos; java.lang.NumberFormatException: For input string: &apos;Himanshu@123&apos; at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043) at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110) at java.lang.Double.parseDouble(Double.java:538) </pre> <h2>Example 4</h2> <pre> import java.util.Scanner; public class Double_parseDoubleMethodExample4 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); try { System.out.print(&apos;Enter any string:&apos;); String str = scanner.next(); Double d1 = Double.parseDouble(str); String str1=&apos;null&apos;; Double d2 = Double.parseDouble(str1); System.out.println(&apos;1. Double value = &apos; + d1); System.out.println(&apos;2. Double value = &apos; + d2); }catch (NullPointerException e){ System.out.println(&apos;An exception &apos;+e+&apos; has occured.
Plz enter a valid double integer&apos;); }catch (NumberFormatException ex){ System.out.println(&apos;An exception &apos;+ex+&apos; has occured.
Plz enter a valid double integer&apos;); } } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Enter any string:himanshu@123 An exception java.lang.NumberFormatException: For input string: &apos;himanshu@123&apos; has occured. Plz enter a valid double integer </pre> <br></1965){>

Voorbeeld 3

 import java.util.Scanner; public class Double_parseDoubleMethodExample3 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print('Enter any string:'); String str = scanner.next(); Double d1= Double.parseDouble(str); System.out.println('Double value = '+ d1); } } 

Uitgang:

 Enter any string:Himanshu@123 Exception in thread 'main' java.lang.NumberFormatException: For input string: 'Himanshu@123' at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043) at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110) at java.lang.Double.parseDouble(Double.java:538) 

Voorbeeld 4

 import java.util.Scanner; public class Double_parseDoubleMethodExample4 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); try { System.out.print('Enter any string:'); String str = scanner.next(); Double d1 = Double.parseDouble(str); String str1='null'; Double d2 = Double.parseDouble(str1); System.out.println('1. Double value = ' + d1); System.out.println('2. Double value = ' + d2); }catch (NullPointerException e){ System.out.println('An exception '+e+' has occured.
Plz enter a valid double integer'); }catch (NumberFormatException ex){ System.out.println('An exception '+ex+' has occured.
Plz enter a valid double integer'); } } } 

Uitgang:

 Enter any string:himanshu@123 An exception java.lang.NumberFormatException: For input string: 'himanshu@123' has occured. Plz enter a valid double integer