Map的几种循环方式

for(String dataKey : paraMap.keySet()) {
System.out.println(dataKey );
}

for(Map.Entry<String, Object> entry : paraMap.entrySet()) {
System.out.println(entry.getKey()+": "+entry.getValue());
}

Iterator it = paraMap.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pairs = (Map.Entry)it.next();
System.out.println(pairs.getKey() + " = " + pairs.getValue());
}