java入门到基础运用

如有帮助，点击我回答右上角【采纳】按钮。

import java.util.Scanner;

public class User {
    private String name;
    private String password;
    private String sex;
    private Integer age;
    public String getPassword() {
        return password;
    }
    public String getName() {
        return name;
    }

    public User(String name, String password, String sex, Integer age) {
        this.name = name;
        this.password = password;
        this.sex = sex;
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age='" + age + '\'' +
                '}';
    }

    public static void main(String[] args) {
        User [] users=new User[3];
        Scanner in=new Scanner(System.in);
       for(int i=0;i<3;i++){
           System.out.println("请输入"+(i+1)+"用户信息：");
           System.out.println("请依次输入用户名、密码、性别、年龄：");
           String name=in.next();
          while (getUser(name,users)){
              System.out.println("用户名不能重复，请重新输入！");
              name=in.next();
          }
          User user=new User(name,in.next(),in.next(),in.nextInt());
          users[i]=user;
       }
        System.out.println("循环创建用户成功");

       //登陆
        System.out.println("请输入用户名：");
        String name=in.next();
        System.out.println("请输入密码：");
        String password=in.next();
        if (name=="" ||password==""){
            System.out.println("用户名或密码为空");
        }else{
            boolean flag=getLogin(name,password,users);
            if (flag){
                System.out.println("登陆成功，欢迎"+name);
            }else{
                System.out.println("用户名或密码错误");
            }
        }
    }
    public static boolean getLogin(String name,String password,User [] users){
        for (User user:users) {
            if (user.getName().equals(name)&&user.getPassword().equals(password)){
                return true;
            }
        }
        return false;
    }

    public static boolean getUser(String name,User [] users){
        for (User user:users) {
            if (user.getName().equals(name)){
                return true;
            }
        }
        return false;
    }
}