ArrayList＜ArrayList＜String＞＞和ArrayList＜String[]＞创建性能的简单测试

直接上代码

public static void main(String args[]) {

        long start = System.currentTimeMillis();
        ArrayList<ArrayList<String>> arrayLists = new ArrayList<ArrayList<String>>();
        for (int i = 0; i < 1000000; i++) {
            ArrayList<String> strings = new ArrayList<String>();
            for(int x=0;x<20;x++){
            	strings.add("string这是第"+i+"个元素");
			}
            arrayLists.add(strings);
        }
        long after = System.currentTimeMillis();
        System.out.println("总共花费的时间为："+(after-start));

        long start2 = System.currentTimeMillis();
          ArrayList<String[]> list = new ArrayList<String[]>();

        for (int i = 0; i < 1000000; i++) {
            String[] str = new String[20];
           for(int x=0;x<20;x++){
            	str[x] = "string[]这是第"+i+"个元素";
			}
            list.add(str);
        }
        long after2 = System.currentTimeMillis();
        System.out.println("总共花费的时间为："+(after2-start2));

    }
        
        */
    }

arrayList总共花费的时间为：2868
String总共花费的时间为：2242

Process finished with exit code 0