java中兩個map比較

標籤：null   迭代器   bsp   str   for迴圈   java   效率   void   public   

一

    /**     * 用map的keySet()的迭代器(效能效率較低)     *      */    public  void compareMap1 (){         Map<String, String> m1 = new HashMap<String, String>();        Map<String, String> m2 = new HashMap<String, String>();         Iterator<String> iter1 = m1.keySet().iterator();         while (iter1.hasNext()) {            String m1Key = (String) iter1.next();            if (!m1.get(m1Key).equals(m2.get(m1Key))) {//若兩個map中相同key對應的value不相等                //......            }        }     }

 

二

   /**     * 用map的entrySet()的迭代器(效能效率較高)     */    public void compareMap2(){        Map<String, String> m1 = new HashMap<String, String>();        Map<String, String> m2 = new HashMap<String, String>();                 Iterator<Entry<String, String>> iter1 = m1.entrySet().iterator();        while(iter1.hasNext()){            Map.Entry<String, String> entry1 = (Entry<String, String>) iter1.next();　　　　　　　String m1value = entry1.getValue() == null?"":entry1.getValue();            String m2value = m2.get(entry1.getKey())==null?"":m2.get(entry1.getKey());                              if (!m1value.equals(m2value)) {//若兩個map中相同key對應的value不相等                //其他動作...            }        }    }

 

三

    /**     * 用map的entrySet()的增強型for迴圈(效能效率較高)     */    public void compareMap3(){         Map<String, String> m1 = new HashMap<String, String>();         Map<String, String> m2 = new HashMap<String, String>();                   for(Map.Entry<String, String> entry1:m1.entrySet()){             String m1value = entry1.getValue() == null?"":entry1.getValue();             String m2value = m2.get(entry1.getKey())==null?"":m2.get(entry1.getKey());             if (!m1value.equals(m2value)) {//若兩個map中相同key對應的value不相等                //其他動作...            }         }     }

 

java中兩個map比較