Java 字符串与字符的转换，字符串单个字符的修改

	public static void main(String[] args) {
		String word = "myWord";
		char[] arr = word.toCharArray();
		arr[1] = (char) ('a' + 3);
		word = new String (arr);
		for (int i = 0; i < word.length(); i++) {
			System.out.println(arr[i]);
		}
		
		System.out.println(word);
	}
	public static void main(String[