Collections.sort Comparator.comparing 冒泡排序 效率對比

public static void main(String[] args) {
			Long t = System.currentTimeMillis();
			Random random = new Random();
			List<Apple> list = new ArrayList<Apple>();
			for (int j = 0; j < 1000000; j++) {
				Apple a = new Apple("Apple"+1,random.nextInt(1000000));
				list.add(a);
			}
			Long t2 = System.currentTimeMillis();
			System.out.println(t2-t);
			//以下四種排序方式，任意打開一個
//			list.sort(java.util.Comparator.comparing(Apple::getWeight));
			
			list.sort((Apple a1, Apple a2)
					-> a1.getWeight()-a2.getWeight()
					);
			
//			Collections.sort(list, new Comparator<Apple>() {
//	            public int compare(Apple o1, Apple o2) {
//	                return o2.getWeight()-o1.getWeight();
//	            }
//	        });
			
//			for(int j = 0; j < list.size(); j++){
//				for(int m = j+1; m < list.size(); m++){
//					Apple a2 = list.get(j);
//					if(a2.getWeight()>list.get(m).getWeight()){
//						Apple am = list.get(m);
//						am.setWeight(a2.getWeight()); 
//						a2.setWeight(am.getWeight()); 
//					}
//				}
//			}
			
			for (int j = 0; j < 1000000; j++) {
				Apple a = list.get(j);
				//打印驗證是否排序成功開關
				//System.out.println(a.getWeight());
			}
			Long t3 = System.currentTimeMillis();
			System.out.println(t3-t2);
			
		
			
		}

　　

結論：不管數據量的多少，用Collections.sort，遠優於另外兩個，數據量少（萬以下，沒細測）用冒泡優於Comparator.comparing，數據量最大，冒泡越耗時，綜合結論，sort 優於 comparing 優於 冒泡