java 对象数组的排序（实现Comparable接口）和二分查找

package practice;

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

/**
 * Created by fangjiejie on 2016/12/4.
 */
//正常数组
public class Array
{
    public static void main(String[] args) {
        int a[]={1,2,4,5,3,8,9};
        int b[]= Arrays.copyOf(a,2);
        int c[]=new int[10];
        System.arraycopy(a,2,c,0,3);
        for(int i:c){
            System.out.println(i);
        }
    }
}
//对象数组
class AAA implements Comparable{//实现对对象的排序
    @Override
    public int compareTo(Object o) {//核心比较算法 0,<0,>0
        AAA obj=(AAA)o;
        /*if(this.age>obj.age){//按照age从小到大排
            return 1;
        }
        else if(this.age=<obj.age){
            return -1;
        }*/
        //return -(this.age-obj.age);//按照age从大到小排
        //return this.age-obj.age;//按照age从小到大排
        return this.age-obj.age==0?this.name.compareTo(obj.name):this.age-obj.age;
                                  //按照age从小到大排,如果年龄相等按照name的字典序排序
    }

    int age;
    String name;
    AAA(){

    }
    public AAA(int age, String name) {
        this.age = age;
        this.name = name;
    }
    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public static void main(String[] args) {
        AAA a[]={
                new AAA(6,"Tom"),
                new AAA(6,"Ahh"),
                new AAA(11,"Marry"),
                new AAA(9,"Mike")
        };
        Arrays.sort(a);//对象数组的排序和对象数组的二分查找
        for(AAA i:a){
            System.out.println(i.getName());
        }
        System.out.println(Arrays.binarySearch(a,new AAA(11,"Marry")));
    }
}

java 使用Arrays对二维数组个性化排序：

Arrays.sort(people, Comparator.comparingInt(o -> o[0]));