Java provides various built-in interfaces that we can use to perform various operations. In this tutorial, we will discuss two such interfaces i.e. Comparable and Comparator. A comparable interface is used for sorting object according to the natural ordering. Comparator interface is used to sort ...
1 public interface Comparator<T> { 2 int compare(T first, T second); 3 } 如果要按照字符串长度进行比较,可以先声明一个一个实现了 Comparator 接口的比较类: 1 class LenComparator implements Comparator<String> { 2 public int compare(String first, String second) { 3 return first.length() - se...
} Comparator 接口 LengthComparator importjava.util.Comparator;// 按照长度比较字符串publicclassLengthComparatorimplementsComparator<String> {@Overridepublicintcompare(Stringfirst,Stringsecond) {returnfirst.length() - second.length(); } } Compatator接口测试 import sun.rmi.runtime.Log; import java.util.*...
同样准备一个Telephone对象数组,使用Arrays.sort()对其进行排序,注意这次需要传入一个Comparator接口的实现来指定排序规则(这次依次使用countryCode、areaCode和number进行倒序排序),最后打印排序后的数组: // src/test/java/ComparatorTest.java importorg.junit.jupiter.api.Test; importjava.util.Arrays; importjava.util...
java.util@FunctionalInterface// 函数式接口publicinterfaceComparator<T>{// 比较其两个参数。intcompare(To1,To2);// JDK1.8 之后增加了很多其他的静态方法...参见 API 文档} Comparator 则是在外部制定排序规则,然后作为排序策略参数传给某些类。
import java.util.Collections; import java.util.Comparator; import java.util.Random; class Student { int num, grade; String name; public int getNum() { return num; } public void setNum(int num) { this.num = num; } public int getGrade() { ...
Java中有两个用于比较和排序的接口Comparable和Comparator。它们一个位于java.lang包中,一个位于java.util包中。Comparable主要是用于在创建一个类时来实现该接口,使得该类的对象自身可以用于比较,进而可以对其实例组成的数组和集合进行排序。 例如,Java自带的String,Integer类都默认实现了该接口,使得它们的实例自己拥有了...
Comparator Comparator 是java.util包中的一个接口，它的底层构造相比较Comparable要复杂的多了，不过我们...
Comparable and Comparator both are interfaces and can be used to sort collection elements. But what's the difference between them: Comparable :This interface has one methodcompareTo.Class whose objects to be sorted must implement this Comparable interface. In this case there is one form or way ...
Comparator接口源码: public interface Comparator<T> { int compare(T o1, T o2); boolean equals(Object obj); } 可以看到Comparator接口中包含两个抽象抽象方法,分别是为compare, equals,但类实现此接口时,只需要实现的接口只有compare方法即可; Java中类都继承于Object类,而Object类默认实现了equals方法,所以类...