JAVA字符串的一些特殊应用——数字变成字符串并位数补足0等

public class StringManager {
	/**
	 * 将字符串转为字母串
	 * @param str
	 * @return
	 */
	public String changeToLetter(String str){
		String result = "";
		String[] arr = new String[]{"A","B","C","D","E","F","G","H","I","J"}; 
		for(int i = 0; i