package untitled4;
import java.util.*;
class compare implements Comparator
{
    public int compare(Object o1,Object o2)
    { 
        int i=((Person)o1).getFirstName().compareTo(((Person)o2).getFirstName());
        return (i!=0?i:((Person)o1).getLastName().compareTo(((Person)o2).getLastName()));
    }
}
class Person implements Comparable
{   private String firstName;
    private String lastName;
    public String getFirstName()
    {
      return firstName;
    }
    public String getLastName()
    {      return lastName;
    }
    public Person(String f,String l)
    {
       firstName=f;
       lastName=l;
    }
    public int compareTo(Object o)
    {  Person p=(Person)o;
        int l=firstName.compareTo(p.firstName);
       return (l!=0?l:(lastName.compareTo(p.lastName)));
    }
    public String toString()
    {
        return firstName+" "+lastName;
    }

}
public class ArrayTest {
    public ArrayTest() {
    }
public static void main(String args[])
    {
        int a[];
        a = new int[5];
        Arrays.fill(a, 5);  //用5填充数组
        for (int i = 0; i < a.length; i++) {
            System.out.println(a[i]);
        }
        int b[] = {10, 3, 5, 6, 8, 9};
        Arrays.sort(b);
        for (int i = 0; i < b.length; i++) {
            System.out.println(b[i]);
        }
   
        Person p[] = {
                     new Person("John", "Lennon"),
                     new Person("Karl", "Marx"),
                     new Person("Groucho", "Marx"),
                     new Person("Oscar", "Grouch")
        };
        for (int i = 0; i < p.length; i++) {
            System.out.println(p[i]);
        }
   
        //Arrays.sort(p);
        Arrays.sort(p, new compare());
        for (int i = 0; i < p.length; i++) {
           System.out.println(p[i]);
       }

        int s = Arrays.binarySearch(p, new Person("Groucho", "Marx"), new compare());
        System.out.println(s);
        Person person[];
        person = new Person[4];
        System.arraycopy(p, 0, person, 0, p.length);
        for (int c= 0; c < person.length; c++)
        {
            System.out.println(person[c]);
   
        }
    }
}
当用Arrays的sort方法时,需要排序的数组必须实现Comparable借口.或者实现Comparator接口
Arrays的fill方法是用一个基本类型或者一个对象填充数组.
当调用binarySearch()时如果是调用sort(Objiec a[],Comparator a)时,,应调用相应的binarySearch(Object a[],Object value,Comparator)方法.
equals()方法用于比较非基本类型数组时,调用他们的equals方法..比如
 int a[]={5,4,3,2,1};
 int c[]={5,4,3,2,1};  基本类型比较他们的值,
 System.out.println(Arrays.equals(a,c));  TRUE
Integer a[]={new Integer(1),new Integer(2),new Integer(3)};
Integer b[]={new Integer(1),new Integer(2),new Integer(3)};
System.out.println(Arrays.equals(a,b));   调用Integer.equals()方法
对于没有覆盖Object equals方法的对象数组,他们之间比较的是对象的引用.
System.arraycopy()方法对与基本类型来说只是复制他们的值.而对于非基本类型时他们复制引用
  person person[]={new person("guo",20),new person("cher",21)};
         person per[]={new person("guo",20),new person("cher",21)};
       person []p=new person[2];
       System.arraycopy(person,0,p,0,person.length);
       System.out.println(person==p);    //输出  false
       person[1].setName("hao");
       System.out.println(person[1].equals(p[1]));  输出 true
       System.out.println(Arrays.equals(person,p));   输出 true
        System.out.println(Arrays.equals(person,per));  输出 false