TreeSet的简单使用

仅仅是使用方法，非源码分析。

public class Test {

public static void main(String[] args) {
TreeSet<String> treeSet=new TreeSet<>();
treeSet.add("Se");
treeSet.add("Ald");
treeSet.add("Boo");
treeSet.add("CC");
Iterator<String> iterator=treeSet.iterator();
while (iterator.hasNext()) {
String string = (String) iterator.next();
System.out.println(string);
}
}

}

输出：

Ald
Boo
CC
Se

使用TreeSet集合时，元素必须实现Comparable接口。

public class Person implements Comparable<Person> {
private String name;
private int age;

public Person() {
// TODO Auto-generated constructor stub
}

public Person(String name, int age) {
this.name = name;
this.age = age;
}

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;
}

@Override
public String toString() {
// TODO Auto-generated method stub
return "name:" + getName() + "  age:" + getAge();
}

/**
* 升序排列
*/
@Override
public int compareTo(Person person) {
// TODO Auto-generated method stub
if (this.getAge() > person.getAge()) {
return 1;
} else if (this.getAge() == person.getAge()) {
return 0;
} else {
return -1;
}
}

}

测试类：

public class Test {

public static void main(String[] args) {
// TODO Auto-generated method stub
TreeSet<Person> tSet = new TreeSet<>();
tSet.add(new Person("shldom", 23));
tSet.add(new Person("tom", 12));
tSet.add(new Person("woa", 45));
tSet.add(new Person("moe", 87));
Iterator<Person> iterator=tSet.iterator();
while(iterator.hasNext()){
System.out.println(iterator.next());
}
}

}

输出结果：

name:tom age:12
name:shldom age:23
name:woa age:45
name:moe age:87