Java get String CompareTo as a comparator object

You may write your own comparator

public class ExampleComparator  implements Comparator<String> {
  public int compare(String obj1, String obj2) {
    if (obj1 == obj2) {
        return 0;
    }
    if (obj1 == null) {
        return -1;
    }
    if (obj2 == null) {
        return 1;
    }
    return obj1.compareTo(obj2);
  }
}

Solution for Java 8 based on java.util.Comparator.comparing(...):

Comparator<String> c = Comparator.comparing(String::toString);

Comparator<String> c = Comparator.comparing((String x) -> x);

The Arrays class has versions of sort() and binarySearch() which don't require a Comparator. For example, you can use the version of Arrays.sort() which just takes an array of objects. These methods call the compareTo() method of the objects in the array.

If you do find yourslef needing a Comparator, and you already use Guava, you can use Ordering.natural().

Ok this is a few years later but with java 8 you can use Comparator.naturalOrder():

http://docs.oracle.com/javase/8/docs/api/java/util/Comparator.html#naturalOrder--

From javadoc:

static <T extends Comparable<? super T>> Comparator<T> naturalOrder()

Returns a comparator that compares Comparable objects in natural order. The returned comparator is serializable and throws NullPointerException when comparing null.

Java get String CompareTo as a comparator object

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