Java Arrays自定义排序的五种写法
package com.javaLearn.customSort_;
import java.util.Arrays;
import java.util.Comparator;
public class Sort01 {
public static void main(String[] args) {
A[] arr = new A[4];
arr[0] = new A("aaa", 10);
arr[1] = new A("cc", 8);
arr[2] = new A("dddd", 11);
arr[3] = new A("bb", 3);
// 类实现Comparable接口
Arrays.sort(arr);
System.out.println(Arrays.toString(arr));
// 创建实现Comparator的类/匿名类
Arrays.sort(arr, new Comparator<A>() {
@Override
public int compare(A o1, A o2) {
return o1.getName().compareTo(o2.getName());
}
});
System.out.println(Arrays.toString(arr));
Arrays.sort(arr, new Tools());
System.out.println(Arrays.toString(arr));
// 基于Comparator构建Lambda表达式
Comparator<A> comp = (A o1, A o2) -> {
return o1.getGrade() - o2.getGrade();
};
Arrays.sort(arr, comp);
System.out.println(Arrays.toString(arr));
// Comparator类的comparing方法，可以搭配lambda表达式
Arrays.sort(arr, Comparator.comparing(A::getGrade).thenComparing(A::getName));
System.out.println(Arrays.toString(arr));
Arrays.sort(arr, Comparator.comparing(A::getName,
((o1, o2) -> {return o1.length() - o2.length();})
));
System.out.println(Arrays.toString(arr));
// Comparator类的comparingInt方法，可以搭配lambda表达式，comparing的变体
Arrays.sort(arr, Comparator.comparingInt(o -> o.getName().length()));
System.out.println(Arrays.toString(arr));
}
}
class A implements Comparable<A>{
private String name;
private int grade;
public A(String name, int grade) {
this.name = name;
this.grade = grade;
}
public String getName() {
return name;
}
public int getGrade() {
return grade;
}
@Override
public String toString() {
return "A{" +
"name='" + name + '\'' +
", grade=" + grade +
'}';
}
@Override
public int compareTo(@NotNull A o) {
return grade - o.grade;
}
}
class Tools implements Comparator<A> {
@Override
public int compare(A o1, A o2) {
return o1.getGrade() - o2.getGrade();
}
}