Java中迭代Map的方法

Map<String, String> mapServlet = new HashMap<String, String>();
System.out.println("迭代方法一");
for( Object key:mapServlet.keySet()){
System.out.println( key );
System.out.println(mapServlet.get(key));
}
System.out.println("迭代方法二");
for( Object value: mapServlet.values()){
System.out.println(value);
}
System.out.println("迭代方法三");
for(Iterator iterator = mapServlet.entrySet().iterator();iterator.hasNext();){
Object keyObject = iterator.next();
System.out.println(keyObject);
}
System.out.println("迭代方法四");
for(Iterator iterator = mapServlet.entrySet().iterator();iterator.hasNext();){
Map.Entry entry = (Entry)iterator.next();
System.out.println(entry.getKey());
System.out.println(entry.getValue());
}