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java Map ±éÀúËÙ¶È×îÓŽâ

µÚÒ»ÖÖ:
Map map = new HashMap();
Iterator iter = map.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry entry = (Map.Entry) iter.next();
Object key = entry.getKey();
Object val = entry.getValue();
}
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µÚ¶þÖÖ:
Map map = new HashMap();
Iterator iter = map.keySet().iterator();
while (iter.hasNext()) {
Object key = iter.next();
Object val = map.get(key);
}
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HashMapµÄ±éÀúÓÐÁ½ÖÖ³£Óõķ½·¨£¬ÄǾÍÊÇʹÓÃkeyset¼°entrysetÀ´½øÐбéÀú£¬µ«Á½ÕߵıéÀúËÙ¶ÈÊÇÓвî±ðµÄ£¬ÏÂÃæÇ뿴ʵÀý£º
public class HashMapTest {
public static void main(String[] args) ...{
HashMap hashmap = new HashMap();
for (int i = 0; i < 1000; i ) ...{
hashmap.put("" i, "thanks");
}
long bs = Calendar.getInstance().getTimeInMillis();
Iterator iterator = hashmap.keySet().iterator();
while (iterator.hasNext()) ...{
System.out.print(hashmap.get(iterator.next()));
}
System.out.println();
System.out.println(Calendar.getInstance().getTimeInMillis() - bs);
listHashMap();
}
public static void listHashMap() ...{
java.util.HashMap hashmap = new java.util.HashMap();
for (int i = 0; i < 1000; i ) ...{
hashmap.put("" i, "thanks");
}
long bs = Calendar.getInstance().getTimeInMillis();
java.util.Iterator it = hashmap.entrySet().iterator();
while (it.hasNext()) ...{
java.util.Map.Entry entry = (java.util.Map.Entry) it.next();
// entry.getKey() ·µ»ØÓë´ËÏî¶ÔÓ¦µÄ¼ü
// entry.getValue() ·µ»ØÓë´ËÏî¶ÔÓ¦µÄÖµ
System.out.print(entry.getValue());
}
System.out.println();
System.out.println(Calendar.getInstance().getTimeInMillis() - bs);
}
}
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