获取字符串已utf-8表示的字节数

 1 private static int utf8Length(String string) { /** Returns the number of bytes required to write this. */
 2     int stringLength = string.length();
 3     int utf8Length = 0;
 4     for (int i = 0; i < stringLength; i++) {
 5       int c = string.charAt(i);
 6       if (c <= 0x007F) {
 7         utf8Length++;
 8       } else if (c > 0x07FF) {
 9         utf8Length += 3;
10       } else {
11         utf8Length += 2;
12       }
13     }
14     return utf8Length;
15   }

当然我们是可以直接使用String.getBytes("utf-8"),但是效率方面肯定不如上面的代码