ArraysAPI和案例

package arrays;

import java.util.Arrays;

public class ArraysDemo1 {
public static void main(String[] args) {
int[] arr = {1,2,4,6,5,7,8,9};
System.out.println(arr);
//toString返回数组内容的
System.out.println(Arrays.toString(arr));
//排序API 对数组进行升序排序
Arrays.sort(arr);
System.out.println(Arrays.toString(arr));
//二分搜索
int i = Arrays.binarySearch(arr,1);
System.out.println(i);

    int i1 = Arrays.binarySearch(arr, 3);
    System.out.println(i1);//返回索引所在位置并加上(-1)得到的结果
    //注意：数组需要排序才能使用二分查找法查找，否则会出bug
}

}

(案例：先建学生类，创建getset方法，toString方法，以及有参无参构造器，以下是main方法)
package arrays;

import java.util.Arrays;
import java.util.Comparator;

public class ArraysDemo2 {
public static void main(String[] args) {
Student[] students = new Student[3];
students[0] =new Student(“Deresa”,20,145.0);
students[1] =new Student(“Bronya”,17,147.0);
students[2] =new Student(“Seele”,17,149.0);
System.out.println(Arrays.toString(students));
//Arrays.sort(students);//直接运行会崩溃
Arrays.sort(students, new Comparator() {
@Override
public int compare(Student o1, Student o2) {
//return o1.getAge() - o2.getAge();//int类型比较
return Double.compare(o1.getHeight(),o2.getHeight());//double类型比较
}
});
System.out.println(Arrays.toString(students));
}
}