Map迭代（六种）
1 Map<Integer,String> map = new HashMap<Integer,String>(); 2 map.put(1, "a"); 3 map.put(2, "b"); 4 5 System.out.println("(1):"); 6 //1.Map输出1(只遍历一次,速度快) 7 Iterator itr11 = map.entrySet().iterator(); 8 while(itr11.hasNext()){ 9 Map.Entry e = (Map.Entry)itr11.next(); 10 System.out.println(e.getKey()+"==="+e.getValue()); 11 } 12 System.out.println(); 13 System.out.println("(2):"); 14 //2.Map输出2（速度慢） 15 Set set = map.keySet();//用接口实例接口 16 Iterator itr22 = set.iterator(); 17 while(itr22.hasNext()){//遍历二次,速度慢 18 Integer key = (Integer)itr22.next(); 19 System.out.println(key+"==="+map.get(key)); 20 } 21 //3.Map输出3（for语句） 22 System.out.println(); 23 System.out.println("(3):"); 24 Set<Integer> set00 = map.keySet(); 25 for(Integer s :set00){ 26 System.out.println(s+"==="+map.get(s)); 27 } 28 29 //4.Map输出4 30 System.out.println(); 31 System.out.println("(4):"); 32 Iterator itr44 = map.values().iterator(); 33 while(itr44.hasNext()){ 34 System.out.println(itr44.next()); 35 } 36 System.out.println(); 37 38 //5.Map输出5 39 System.out.println("(5):"); 40 System.out.println(map); 41 42 //6.Map输出6 43 System.out.println(); 44 System.out.println("(6):"); 45 for(Map.Entry en:map.entrySet()){ 46 System.out.println(en.getKey()+"==="+en.getValue()); 47 }
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