自定义异常后，使用时出现的问题

Question

public class Demo {
    static String usernames[] ={"张三李四","张三","李四"};
    public static void main(String[] args) throws RegisterException {
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入你的名字");
        String username= sc.next();
        check(username);
    }
    public static void check (String username) throws RegisterException {
        for (int i=0;i< usernames.length;i++) {
            if(username.equals(usernames)){
                throw new RegisterException("该用户已经被注册");
            }else {
                System.out.println("成功");
            }
            }

        }
    }

为啥我的代码每次运行的时候都是成功啊，RegisterException是我自定义的异常，请吴彦祖，彭于晏帮忙看看，谢谢了！

Answer 1

usernames是数组啊，怎么会跟你的string一样呢，这样使用下标循环数组对比

public class Demo {
 static String usernames[] ={"张三李四","张三","李四"};
            public static void main(String[] args) throws Exception {
                Scanner sc=new Scanner(System.in);
                System.out.println("请输入你的名字");
                String username= sc.next();
                check(username);
            }
            public static void check (String username) throws Exception {
                for (int i=0;i< usernames.length;i++) {
                    if(username.equals(usernames[i])){
                        throw new Exception("该用户已经被注册");
                    } 
                      
                    }
                System.out.println("成功");
                }
}