【java】数组的常用操作

sort

static void sort(int[] a) ：将a数组按照从小到大进行排序
static void sort(int[] a, int fromIndex, int toIndex) ：将a数组的[fromIndex, toIndex)部分按照升序排列
static void sort(Object[] a) ：根据元素的自然顺序对指定对象数组按升序进行排序。
static <T> void sort(T[] a, Comparator<? super T> c) ：根据指定比较器产生的顺序对指定对象数组进行排序。

需要自己定义比较器

import org.junit.Test;

import java.text.Collator;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Locale;

public class TestArrays {

    @Test
    public void test02() {
        int[] arr = {3, 2, 5, 1, 6};
        System.out.println("排序前" + Arrays.toString(arr));
        Arrays.sort(arr);
        System.out.println("排序后" + Arrays.toString(arr));

        Student[] students = new Student[3];
        students[0] = new Student("张三", 96);
        students[1] = new Student("李四", 85);
        students[2] = new Student("王五", 98);

        System.out.println(Arrays.toString(students));
        Arrays.sort(students);
        System.out.println(Arrays.toString(students));
        Arrays.sort(students, new Comparator() {
            @Override
            public int compare(Object o1, Object o2) {
                return Collator.getInstance(Locale.CHINA).compare(((Student) o1).getName(), ((Student) o2).getName());
            }
        });
        System.out.println(Arrays.toString(students));
    }
}


class Student implements Comparable {
    private String name;
    private int score;

    public Student(String name, int score) {
        this.name = name;
        this.score = score;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", score=" + score +
                '}';
    }

    @Override
    public int compareTo(Object o) {
        return this.score - ((Student)o).score;
    }
}