封装

import java.util.Scanner;

public class deng {
public void wolcome(){
Scanner in=new Scanner(System.in);
int key = 0;
yan y=new yan();
System.out.println("尊敬的客户，请选择操作类型");
System.out.println("1.登录系统");
System.out.println("2.注册用户");
System.out.println("3.退出系统");
key=in.nextInt();
switch (key) {
case 1:
y.denglu();
break;
case 2:
y.zhu();
this.wolcome();
break;
case 3:
System.out.println("退出成功");
break;
default:
break;
}
}
public static void main(String[] args) {
deng de=new deng();
de.wolcome();

}

}

**********************************************************

public class yan {
boolean falg;
int count=0;
String id1="123";
String pwd1="456";
public void denglu(){
Scanner in=new Scanner(System.in);
if(count>=3){
System.out.println("登录错误已达三次，强制退出");
}else{
System.out.println("请输入账号");
String id=in.next();
System.out.println("请输入密码");
String pwd=in.next();
if(id1.equals(id)&&pwd1.equals(pwd)){
System.out.println("登录成功！");
}else{
System.out.println("密码错误，登录失败！");
count++;
denglu();
}
}
}

public boolean zhu(){

Scanner in=new Scanner(System.in);
System.out.println("请输入账号");
String id1=in.next();
System.out.println("请输入密码");
String pwd1=in.next();
System.out.println("注册成功！");
System.out.println("账号为："+id1+""+"密码为："+pwd1);
if(count>=3){
System.out.println("登录错误已达三次，强制退出");
}else{
System.out.println("请输入账号");
String id=in.next();
System.out.println("请输入密码");
String pwd=in.next();
if(id1.equals(id)&&pwd1.equals(pwd)){
System.out.println("登录成功！");
}else{
System.out.println("密码错误，登录失败！");
count++;
this.zhu();

}
}
return falg;
}
}