Java中遍历字符串toCharArray()和charAt()效率比较

public static void test() {

    String s = "a";

    for(int i = 0; i < 100000; i++) {

        s += "a";

    }

    /****************toCharArray遍历*************/

    long start1 = System.currentTimeMillis();

    char[] arr = s.toCharArray();

    for (int i = 0; i < arr.length; i++) {

         char c = arr[i];

         System.out.println(c);

    }

    long end1 = System.currentTimeMillis();

    /****************charAt遍历******************/

    long start2 = System.currentTimeMillis();

    for(int i = 0; i < s.length(); i++) {

        char c = s.charAt(i);

        System.out.println(c);

    }

    long end2 = System.currentTimeMillis();

    System.out.println(end1 - start1);  //503

    System.out.println(end2 - start2);  //453

}  

由此得出charAt效率较高。