如何才能去掉这么多case ,使起逐次输出字符串中的元素，一定用switch。

public static void main(String[] args) throws InterruptedException {

    String str = "abcdefghijklmnop";
    int i = 1;
    switch (i) {
    case 1:
    System.out.println(str.charAt(0));
    case 2:
        System.out.println(str.charAt(1));
    case 3:
        System.out.println(str.charAt(2));  
    case 4:
        System.out.println(str.charAt(3));
    case 5:
        System.out.println(str.charAt(4));
    case 6:
        System.out.println(str.charAt(5));
    case 7:
        System.out.println(str.charAt(6));
    case 8:
        System.out.println(str.charAt(7));
    case 9:
        System.out.println(str.charAt(8));
    case 10:
        System.out.println(str.charAt(9));
    case 11:
        System.out.println(str.charAt(10)); 
    case 12:
        System.out.println(str.charAt(11));
    case 13:
        System.out.println(str.charAt(12));
    case 14:
        System.out.println(str.charAt(13));
    case 15:
        System.out.println(str.charAt(14));
    case 16:
        System.out.println(str.charAt(15));
    }   
}

System.out.println(str.charAt(i - 1));

for (int j = i - 1; j <= 15; j++)
System.out.println(str.charAt(j));