This example shows how to convert double to String in Java using the toString, valueOf, and + operator. It also shows the best way to convert double to string.
How to convert double to String in Java?
There are several ways in which the primitive double value can be converted to a String in Java.
1) Convert double to String using the String class
Use the valueOf static method of the String class to convert.
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static String valueOf(double f) |
The valueOf method returns a string representation of the double argument.
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package com.javacodeexamples.basic; public class DoubleToStringExample { public static void main(String[] args){ double d = 3424.6456d; String strNumber = String.valueOf(d); System.out.println("String value: " + strNumber); } } |
Output
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String value: 3424.6456 |
2) Using the Double wrapper class
Use the toString method of the Double wrapper class to convert.
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public static String toString(double d) |
This method returns a string representation of double value passed as a parameter.
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double d = 3424.6456d; String strNumber = Double.toString(d); System.out.println("String value: " + strNumber); |
Output
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String value: 3424.6456 |
3) Using string concatenation
String concatenation can be indirectly used to convert any Java primitive values to String as given below.
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double d = 3424.6456d; String strNumber = "" + d; System.out.println("String value: " + strNumber); |
Output
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String value: 3424.6456 |
What is the best way to convert?
ThevalueOf method of the String class internally calls the toString method of the Double wrapper class to convert from double to a string value. Using either of the methods is equally efficient in terms of the performance. Preferred way is to use the toString method of the Double wrapper class.
String concatenation should be avoided mainly for the conversion purpose because,
a) It is difficult to visually understand that the intent of code statement is to conversion.
b) String concatenation operation creates unnecessary temporary objects during the conversion process. String concatenation is achieved using the append method of the StringBuilder or StringBuffer class. So the code,
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String strNumber = "" + d; |
Will run like,
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StringBuilder sb = new StringBuilder(); sb.append(""); sb.append(d); String strNumber = sb.toString(); |
This example is a part of the Java Basic Examples and Java Type conversion Tutorial.
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