1.Map方法及其功能
代码模拟实现功能
import java.util.Map;
import java.util.TreeMap;
public class MapDemo {
public static void main(String[] args) {
Map<String,String> map=new TreeMap<>();
System.out.println(map.get("田柾国"));//打印null 刚开始树种无值 所以打印的默认值
System.out.println(map.getOrDefault("田柾国","77777777") );//同样打印默认值 但是此时的默认值指定为7777777
String oldValue=map.put("田柾国","20000101");//设置key对应的value值 如果此时不存在则将其插入
System.out.println(oldValue);//null
oldValue=map.put("田柾国","19970901");//这时的对应key已经存在 所以更新value 值
System.out.println(oldValue);//20000101
map.put("金硕珍","19921204");
map.put("朴智旻","19951013");
map.put("金泰亨","19951230");
System.out.println(map.keySet());//打印所有key值
for(String key:map.keySet()){
System.out.println(key);
}//依次打印二叉树中结点的key值
for (String value : map.values()) {
System.out.println(value);
}//依次打印二叉树中结点的value值
for (Map.Entry<String, String> entry : map.entrySet()) {
System.out.println(entry.getKey() + " = " + entry.getValue());
}//依次打印二叉树中结点的key-value值 按照指定形式进行打印
System.out.println(map.containsKey("田柾国"));//判断树中是否包含key值
System.out.println(map.containsKey("金硕珍"));
System.out.println(map.containsValue("19970901"));
}
}
2.Set方法及其功能
完整代码模拟实现
import java.util.Set;
import java.util.TreeSet;
public class SetDemo {
public static void main(String[] args) {
Set<String> bucket = new TreeSet<>();
bucket.add("苹果");
bucket.add("香蕉");
bucket.add("橘子");
bucket.add("石榴");
bucket.add("柿子");
System.out.println(bucket);//显示所有节点
System.out.println(bucket.size());//结点个数5
System.out.println(bucket.add("橘子"));//false因为不允许重复
System.out.println(bucket);
System.out.println(bucket.size());//5
System.out.println(bucket.remove("苹果"));//true
System.out.println(bucket);
System.out.println(bucket.size());//4
System.out.println(bucket.remove("火龙果"));//false因为不存在
System.out.println(bucket);
System.out.println(bucket.size());//4
System.out.println(bucket.contains("香蕉"));//判断香蕉是否存在
bucket.clear();//清空
System.out.println(bucket);
System.out.println(bucket.size());//0
}
}