map.containsKey、map.containsValue和 list.contains性能的对比

一、程序

public static void main(String[] args) {

List list = new ArrayList();

Map map = new HashMap();

long begin = System.currentTimeMillis();

for(int i=0; i<1000000; i++) {

String str = i +"ABCDsdmsdnsdnsksdsds";

list.add(str);

map.put(str, str +"B");

}

System.out.println("end-----------遍历:"+ (System.currentTimeMillis()-begin) +" 毫秒");

long begin1 = System.currentTimeMillis();

System.out.println(list.contains("999999ABCDsdmsdnsdnsksdsds"));

System.out.println("end-----------list:"+ (System.currentTimeMillis()-begin1) +" 毫秒");

long begin2 = System.currentTimeMillis();

System.out.println(map.containsValue("999999ABCDsdmsdnsdnsksdsdsB"));

System.out.println("end-----------map-Value:"+ (System.currentTimeMillis()-begin2) +" 毫秒");

long begin3 = System.currentTimeMillis();

System.out.println(map.containsKey("999999ABCDsdmsdnsdnsksdsds"));

System.out.println("end-----------map-Key:"+ (System.currentTimeMillis()-begin3) +" 毫秒");

}

 

二、总结：

1、千万级及以上：map.containsKey > map.containsValue > list

2、百万级及以下：map.containsKey > list > map.containsValue

 

三、代码核心：

1、list.contains ：

2、map.containsValue

3、map.containsKey