java自带排序

int a[]={1,2,5,3,6,4};
Arrays.sort(a);//对a升序排序
Arrays.sort(a,0,6);//对a从下标0，到下标5排序

static Student b[]=new Student [4];
for(int i=0;i<4;++i)b[i]=new Student("str", 4-i);
Arrays.sort(b,new Mcompeter());//对数组所有元素排序，Comparator可以用实例，也可以匿名对象
Arrays.sort(b,0,4,new Mcompeter());//对数组从下标0到3排序

static class Student {
     public String name;
     public int age;
     
     public Student(String name,int age){
        this.name = name;
        this.age = age;
     }
     
     public String toString() {
      return "Student [name=" + name + ", age=" + age + "]";
     }
}
static class Mcompeter implements Comparator<Student> 
 {
  @Override
  public int compare(Student o1, Student o2) {
   // TODO 自动生成的方法存根
   if(o1.name.compareTo(o2.name)==0)
   {
    return o1.age-o2.age;
   }
   else return o1.name.compareTo(o2.name);
  }
 }