LAST UPDATED: DECEMBER 1, 2020
How to convert Java String to double
In Java, a String can be converted into a double value by using the Double.parseDouble() method. Also, a String can be converted into a Double object using the Double.valueOf() method.
Whenever a data(numerical) is received from a TextField or a TextArea it is in the form of a String and if we want double type then it is required to be converted into a double before performing any mathematical operation. This is done via parseDouble() method.
1. By Using Double.parseDouble()
Method
The parseDouble() method is a part of the Double class. It is a static method and is used to convert a String into a double.
Example 1:
Here, a String value is converted into double type value by using the parseDouble() method. See the example below.
public class StudyTonight
{
public static void main(String args[])
{
String s="454.90"; //String Decleration
double i = Double.parseDouble(s); // Double.parseDouble() converts the string into double
System.out.println(i);
}
}
454.9
2. Buy Using Double.valueOf()
Method
The valueOf() method is a part of Double class. This method is used to convert a String
into a Double
Object.
Example 2:
Here, a String
value is converted into a double value by using the valueOf()
method.
public class StudyTonight
{
public static void main(String args[])
{
try
{
String s1 = "500.77"; //String declaration
double i1 = Double.valueOf(s1); // Double.valueOf() method converts a String into Double
System.out.println(i1);
String s2 = "mohit"; //NumberFormatException
double i2 = Double.valueOf(s2);
System.out.println(i2);
}
catch(Exception e)
{
System.out.println("Invalid input");
}
}
}
500.77
Invalid input
Example 3:
If we want to convert a value that contains commas then use replaceAll()
method to replace that commas and the use parseDouble()
method to get double value. Here, a String value is converted into double values taking the commas into consideration.
public class StudyTonight
{
public static void main(String args[])
{
String s = "4,54,8908.90"; //String Decleration
//replace all commas if present with no comma
String s1 = s.replaceAll(",","").trim();
// if there are any empty spaces also take it out.
String f = s1.replaceAll(" ", "");
//now convert the string to double
double result = Double.parseDouble(f);
System.out.println("Double value is : "+ result);
}
}
Double value is : 4548908.9