mapmap中的key可以重复吗吗

来源：蜘蛛抓取(WebSpider) 时间：2014-10-28 03:17 标签： eclipse官网
所有Map操作中key的值是不能重复的，例如，HashMap操作时key是不能重复的，如果重复则肯定会覆盖之前的内容，如下代码所示。
范例：Map中的key不允许重复，重复就是覆盖
程序运行结果：
从程序的运行结果中可以发现，第二个内容覆盖了第一个内容，所以此时可以使用Identity HashMap。使用此类时只要地址不相等（key1！=key2），就表示不是重复的key，可以添加到集合中。
范例：使用IdentityHashMap修改程序
程序运行结果：
从程序的运行结果中可以发现，现在的key允许重复，只要两个对象的地址不相等即可。
阅读(...) 评论()有两个MAP,KEY都相同,只有VALUE不同,要做到将VALUE不同的KEY找出来,
yurongfu3544
试试import java.util.HashMimport java.util.Iimport java.util.Mimport java.util.Spublic class $ {public static void main(String[] args) {Map map0 = new HashMap();Map map1 = new HashMap();map0.put("a",1);map0.put("b",2);map0.put("c",3);map1.put("a",11);map1.put("b",12);map1.put("c",13);map1.put("d",14);Set set = map0.keySet();Iterator it = set.iterator();while (it.hasNext()) {String key = it.next();Integer val0 = map0.get(key);Integer val1 = map1.get(key);if (val0 != val1) {System.out.println(key);}}}}结果:bca
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