Java Program to Convert Double to String

A double is a primitive data type used to store decimal values, while String represents a sequence of characters. Converting a double to a String is useful when a numeric value needs to be displayed, concatenated with text, or processed as textual data.

• StringBuilder.append() can be useful when building larger strings.
• DecimalFormat provides more control over numeric formatting

Illustration

Input: 123.456
Output: "123.456"

Different Methods to Convert Double to String

1. Using String.valueOf()

String.valueOf(double) converts the specified double value into its string representation.

class GFG {
    public static void main(String[] args) {

        double number = 123.456;

        String str = String.valueOf(number);

        System.out.println("Double: " + number);
        System.out.println("String: " + str);
    }
}

Double: 123.456
String: 123.456

2. Using Double.toString()

The Double.toString() method returns the string representation of the specified double value.

class GFG {
    public static void main(String[] args) {

        double number = 123.456;

        String str = Double.toString(number);

        System.out.println(str);
    }
}

123.456

3. Using String.format()

String.format() can convert a double into a formatted string. It is useful when a specific number of decimal places is required.

class GFG {
    public static void main(String[] args) {

        double number = 123.456;

        String str = String.format("%.2f", number);

        System.out.println(str);
    }
}

123.46

4. Using StringBuilder.append()

The append() method can add a double value to a StringBuilder. Calling toString() then returns the resulting string.

class GFG {
    public static void main(String[] args) {

        double number = 123.456;

        String str = new StringBuilder()
                .append(number)
                .toString();

        System.out.println(str);
    }
}

123.456

5. Using DecimalFormat

DecimalFormat can convert and format a double value according to a specified pattern.

import java.text.DecimalFormat;

class GFG {
    public static void main(String[] args) {

        double number = 123.456;

        DecimalFormat df = new DecimalFormat("0.00");
        String str = df.format(number);

        System.out.println(str);
    }
}