Question: How do I convert numeric values to Strings with Java?

Converting numeric values to Strings with Java is pretty easy. The String class contains a method named "valueOf()" that can be used, and the numeric classes also contain "toString()" methods that can be used for the conversion.

Let's take a look at a few examples. Assuming that the variable i is an int, f is a float, d is a double, and l (the letter pronounced "el") is a long, the following examples show how you can convert each numeric type to a String.

Using String.valueOf() for the conversions, you'd write the Java code this way:

String s = String.valueOf(i);
String s = String.valueOf(f);
String s = String.valueOf(d);
String s = String.valueOf(l);

Using the toString() method of the numeric classes (Integer, Float, Double, and Long), you'd write the conversions this way:

String s = new Integer(i).toString();
String s = new Float(f).toString();
String s = new Double(d).toString();
String s = new Long(l).toString();

As an additional example, the simple (some people would call it trivial) Java program shown below demonstrates how this is done in a working Java program:

// Convert.java
// A sample Java program by Alvin Alexander, devdaily.com

class Convert {

   public static void main(String[] args) {

      int i    = 100;
      float f  = (float) 200.0;
      double d = 400.0;
      long l   = 100000;

      String s = new String();

      //--------------------------------------------//
      // Examples using "valueOf()" method of the   //
      // String class.                              //
      //--------------------------------------------//

      s = String.valueOf(i);
      System.out.println ("int i = " + s);

      s = String.valueOf(f);
      System.out.println ("float f = " + s);

      s = String.valueOf(d);
      System.out.println ("double d = " + s);

      s = String.valueOf(l);
      System.out.println ("long l = " + s);


      //------------------------------------------------//
      // Examples using the "toString()" method of the  //
      // numeric classes                                //
      //------------------------------------------------//

      s = new Integer(i).toString();
      System.out.println ("int i = " + s);

      s = new Float(f).toString();
      System.out.println ("float f = " + s);

      s = new Double(d).toString();
      System.out.println ("double d = " + s);

      s = new Long(l).toString();
      System.out.println ("long l = " + s);

   }
}

Related links

There is much more content related to Java and the String class on the blog, including these posts:

• A Java toString method that uses reflection to dynamically print class fields
• Use String.format to format a Java String
• A cheat sheet (reference page) for printf format specifiers


• How to convert a Java String to an int
• How to create an array of Strings (or any object) in Java
• A method to return the longest String in a given array of Strings