1 String str = "123abc";
 2 char[] arr = str.toCharArray();    // char数组
 3 for (int i = 0; i < arr.length; i++) {
 4     System.out.println(arr[i]);    // 输出1 2 3 a b c
 5 }
 6 
 7 String str = "123abc";
 8 String[] arr = str.split("");
 9 for (int i = 0; i < arr.length; i++) { // String数组
10     System.out.print(arr[i]); // 输出 1 2 3 a b c
11

1 char[] arr = { 'a', 'b', 'c' };
2 String string = String.copyValueOf(arr);
3 System.out.println(string); // 输出abc