java 遍历map

今天在做数据挖掘，最后进行数据综合分析需要使用Map来保存数据做汇总，所以温习下map的遍历方法，权当再过目一遍:

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Map<String,String> map=new HashMap<String,String>();   map.put("name", "kaka");   //1. 第一种用for循环for(Map.Entry<String, String> entry:map.entrySet()){        System.out.println(entry.getKey()+":"+entry.getValue());   }  //2. 第二种用迭代IteratorSet set = map.entrySet();        Iterator i = set.iterator();        while(i.hasNext()){          Map.Entry<String, String> entry1=(Map.Entry<String, String>)i.next();        System.out.println(entry1.getKey()+":"+entry1.getValue());   }  Set set = map.entrySet();    //3. 用keySet()迭代Iterator it=map.keySet().iterator();   while(it.hasNext()){        String key;        String value;        key=it.next().toString();        value=map.get(key);        System.out.println(key+":"+value);   }  //4. 用entrySet()迭代Iterator it=map.entrySet().iterator();           String key;          String value;   while(it.hasNext()){           Map.Entry entry = (Map.Entry)it.next();                  key=entry.getKey().toString();                  value=entry.getValue().toString();                  System.out.println(key+":"+value);                    }