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This article mainly explains "what are the knowledge points of Sorting in Java". The content of the explanation is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what are the knowledge points of Sorting in Java".

Two interfaces Comparable

Code first:

Package java.lang;public interface Comparable {public int compareTo (To);}

You can see that there is only one method for this interface, and this method has only one parameter, so the class that implements this interface can be compared with the same class. What this method implements is the rule of comparison, that is, it represents how to compare two objects. It returns an integer int:

Returns a positive number, indicating that the current object is larger than the object being compared

Returns 0, which means that the current object is equal to the object being compared

Returns a negative number, indicating that the current object is smaller than the object being compared.

Once the interface is implemented, we can use Arrays.sort () and Collections.sort () for sorting. Otherwise, there is no rule of comparison for the object, and the program must not know how to sort the comparison. Like our commonly used classes String, Integer, Double, Date, etc., JDK helps us implement the Comparable interface, and we can compare and sort such objects directly. For example, the implementation of Date Comparable:

Public int compareTo (Date anotherDate) {long thisTime = getMillisOf (this); long anotherTime = getMillisOf (anotherDate); return (thisTime)

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