Java中的Map集合简单汇总解析

put(K key, V value) 添加数据,如果先前包含该键的映射,则替换旧值
  get(Object key)  返回指定键所映射的值
  Set<Map.Entry<K,V>> entrySet() 返回地址中包含的映射的Set集合
  Set<K> keySet() 返回集合中包含的键的Set集合
  Collection<V> values() 返回集合中包含的值的Collection集合
  remove(Object key) 从该集合中删除指定键的映射

public class Example01 {
  public static void main(String[] args) {
      Map map = new HashMap();
      map.put("1", "老大");
      map.put("2", "老二");
      map.put("3", "老三");
      System.out.println("1"+" : "+map.get("1"));    //根据键获取值
      System.out.println("2"+" : "+map.get("2"));
      System.out.println("3"+" : "+map.get("3"));
  }
}

public class Example04 {
  public static void main(String[] args) {
    Map map = new HashMap();
    map.put("1", "老大");
    map.put("2", "老二");
    map.put("3", "老三");
    Collection values = map.values();
    Iterator it = values.iterator();
    while(it.hasNext()) {
      Object value = it.next();
      System.out.println(value);
    }
  }
}

public class Example02 {
  public static void main(String[] args) {
    Map map = new HashMap();
    map.put("1", "老大");
    map.put("2", "老二");
    map.put("3", "老三");
    Set keySet = map.keySet();      //获取键的集合
    Iterator it = keySet.iterator();      //迭代键的集合
    while(it.hasNext()) {
      Object key = it.next();
      Object value = map.get(key);    //获取每个键所对应的值
      System.out.println(key+" : "+value);
    }
  }
}

public class Example03 {
  public static void main(String[] args) {
    Map map = new HashMap();
    map.put("1", "老大");
    map.put("2", "老二");
    map.put("3", "老三");
    Set set = map.entrySet();
    Iterator it = set.iterator();        //获取迭代器对象
    while(it.hasNext()) {
      Map.Entry entry = (Map.Entry) it.next();        //获取集合中键值对映射
      Object key = entry.getKey();      //获取Entry中的键
      Object value = entry.getValue();      //获取Entry中的值
      System.out.println(key+" : "+value);
    }
  }
}

public class Example05 {
  public static void main(String[] args) {
    Map map = new LinkedHashMap();      //创建Map集合
    map.put("1", "老大");      //存储键和值
    map.put("2", "老二");
    map.put("3", "老三");
    Set keySet = map.keySet();
    Iterator it = keySet.iterator();
    while(it.hasNext()) {
      Object key = it.next();
      Object value = map.get(key);      //获取每个键所对应的值
      System.out.println(key+" : "+value);
    }
  }
}

  Backgroup-color = red
  Font-size = 14px
  Language = chinese

public class Example06 {
  public static void main(String[] args) {
    Properties p = new Properties();    //创建Properties对象
    p.setProperty("Backgroup-color", "red");
    p.setProperty("Font-size ", "14px");
    p.setProperty("Language", "chinese");
    Enumeration names = p.propertyNames();
    while(names.hasMoreElements()) {    //循环遍历所有的键
      String key =(String) names.nextElement();
      String value = p.getProperty(key);    //或获取键对应的值
      System.out.println(key+" = "+value);
    }
  }
}