import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
class People implements Comparable {
private String name;
private int age;
public People(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
@Override
public String toString() {
return "People [name=" + name + ", age=" + age + "]";
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public int compareTo(Object o) {
// TODO Auto-generated method stub
People p = (People) o;
return this.age - p.age;
}
}
public class TreeMapDemo {
public static void main(String[] args) {
TreeMap tm = new TreeMap();
tm.put(new People("撒哈拉沙漠", 21), "lishuai");
tm.put(new People("耶路撒冷", 22), "liqian");
tm.put(new People("普罗旺斯", 23), "liming");
tm.put(new People("撒哈拉沙漠", 22), "lishuai");
Set s = tm.entrySet();
for (Iterator iterator = s.iterator(); iterator.hasNext();) {
Object o = iterator.next();
Map.Entry e = (Map.Entry) o;
Object key = e.getKey();
Object value = e.getValue();
System.out.println(key + "====" + value);
}
}
}
TreeMap的底层是红黑树结构,因此自定义类它需要继承comparable,然后通过compareTo方法来自定义比较方法。其实这都是对以上学过的东西进行复习。
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