創建隨機密碼給出不兼容類型錯誤

Question

到目前爲止，這是我的編碼。我正在製作一個程序幫助用戶隨機創建一個密碼。我在隨機刻字時遇到問題。我已經想到了一個辦法，但它給我一個不兼容的錯誤，我想：

chars[] letters= "abecdefghijklmnopqrstuvwxyz".toCharArray(); 

，這裏是我的時刻碼。

import java.util.Random; 
import java.util.Scanner; 

public class Password 
{ 
    public static void main(String [] args) 
    { 
    char letters; 
    Scanner in = new Scanner (System.in); 
    System.out.println("Please choose from the following menu options:"); 
    System.out.println("[1] Lowercase Letters"); 
    System.out.println("[2] Lowercase & Uppercase Letters"); 
    System.out.println("[3] Lowercase, Uppercase, and Numbers"); 
    System.out.println("[4] Lowercase, Uppercase, Numbers and Punctuation"); 
    System.out.println("[5] Quit"); 
    System.out.println ("Enter Selection:"); 
    int selection = in.nextInt(); 
    System.out.println("Password Length (1-14):"); 
    int length = in.nextInt(); 
    if (selection == 1) 
     letters = "abcdefghisjklmnopqrstuvwxyz".toCharArray(); 
    Stringbuilder sb = new StringBuilder(); 

Answer 1

toCharArray回報的char []和字母是char只有