The String and StringBuffer Classes |
class ReverseString { public static String reverseIt(String source) { int i, len = source.length(); StringBuffer dest = new StringBuffer(len); for (i = (len - 1); i >= 0; i--) { dest.append(source.charAt(i)); } return dest.toString(); } }The toString() Method
It's often convenient or necessary to convert an object to a String because you need to pass it to a method that accepts only String values. For example,System.out.println()
does not accept StringBuffers, so you need to convert a StringBuffer to a String before you can print it. ThereverseIt()
method above uses StringBuffer'stoString()
method to convert the StringBuffer to a String object before returning the String.All classes inheritreturn dest.toString();toString()
from the Object class and many classes in the java.lang package override this method to provide an implementation that is meaningful to that class. For example, the "type wrapper" classes--Character, Integer, Boolean, and the others--all overridetoString()
to provide a String representation of the object.The valueOf() Method
As a convenience, the String class provides the static methodvalueOf()
, You can usevalueOf()
to convert variables of different types to Strings. For example, to print the value of pi:System.out.println(String.valueOf(Math.PI));
The String and StringBuffer Classes |