If statement 请检查这些代码

你能查一下这些代码吗？ 我找不到问题。 如果没有行动！ 它应该检查用户名、密码和年龄。 之后，如果所有细节都是真的，那么答案将是真的，除非答案是假。但如果不回答

import java.util.Scanner;

 public class Class2 {

    public static void main(String[] args) {

        int age;
        String password = "big.110@go";
        String username = "big";

        Scanner keyboardInput = new Scanner(System.in);
        System.out.print("Please enter your Usename: ");
        username = keyboardInput.next();
        System.out.print("Please enter your age: ");
        age = keyboardInput.nextInt();
        System.out.print("Please enter your password: ");
        password = keyboardInput.next();
    if(keyboardInput.next().equals(username)
            && keyboardInput.nextInt() >= 18
            && keyboardInput.equals(password)) {
                System.out.print("Welcome");
            } else {
                System.out.print("Something is wrong!\n Try again");
            }
    }
}

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你在代码中犯了很多错误

import java.util.Scanner;


public class Class2 {
  public static void main(String args[]) {

      int age;
      String password1 = "big.110@go";
      String username1 = "big";

      Scanner keyboardInput = new Scanner(System.in);
      System.out.print("Please enter your Usename: ");
      String username = keyboardInput.nextLine();
      System.out.print("Please enter your password: ");
      String password = keyboardInput.nextLine();
      System.out.print("Please enter your age: ");
      age = keyboardInput.nextInt();

      if(username.equals(username1)
              && password.equals(password1)
              && age>=18 ) {
          System.out.print("Welcome");
      } else {
          System.out.print("Something is wrong!\n Try again");
      }
    }
}

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keyboardInput.next.equalsusername有什么意义？提前提示输入用户名，然后检查其他输入是否与之前输入的相同？我不明白你说的话！你能解释清楚吗？每次你调用keyboardInput.next时，它都会从用户那里获得输入。你提示输入用户名/年龄/密码，然后在键盘输入时再次输入。下一步。equalsusername，我想现在我找到了问题所在！谢谢，请考虑用解释来扩大你的答案。