集合框架-二叉树-实现Comparator方式排序

当元素自身不具备比较性，或者具备的比较性不是所需要的

这时需要让容器自身具备比较性。

定义了比较器，将比较器对象作为参数传递给TreeSet集合构造函数

当两种排序都存在时，以比较器为主

定义一个类，实现Comparator接口，覆盖compare方法import java.util.*;
class Student implements Comparable//该接口强制让学生具备比较性
{
private String name;
private int age;

Student(String name,int age)
{
this.name = name;
this.age = age;
}
public int compareTo(Object obj)
{
if(!(obj instanceof Student))
throw new RuntimeException("不是学生对象");
Student s = (Student)obj;

System.out.println(this.name+"...compateto..."+s.name);
if(this.age>s.age)
return 1;
if(this.age==s.age)
return 0;
return -1;
}
public String getName()
{
return name;
}
public int getAge()
{
return age;
}
}
class TreeSetDemo2
{
public static void main(String[] args)
{
TreeSet ts = new TreeSet();

ts.add(new Student("lisi02",22));
ts.add(new Student("lisi007",20));
ts.add(new Student("lisi09",19));
ts.add(new Student("lisi08",19));
// ts.add(new Student("lisi01",40));

Iterator it = ts.iterator();
while(it.hasNext())
{
Student stu = (Student)it.next();
System.out.println(stu.getName()+"..."+stu.getAge());
}
}
}

class MyCompare implements Comparator
{
public int compare(Object o1,Object o2)
{
Student s1 = (Student)o1;
Student s2 = (Student)o2;

int num = s1.getName().compareTo(s2.getName());
if(num==0)
{
return new Integer()
}
}
}