创建随机密码给出不兼容类型错误

Question

到目前为止，这是我的编码。我正在制作一个程序帮助用户随机创建一个密码。我在随机刻字时遇到问题。我已经想到了一个办法，但它给我一个不兼容的错误，我想：

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

，这里是我的时刻码。

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回报的char []和字母是char只有