public class userManager {public String checkUser(User one,User two) { String str=null; //判斷用戶名是否為空 if(one.getUserName().equals(two.getUserName())){ System.out.println("用戶名為空"); } else if (!(one.getUserName().equals(two.getUserName()))) { ? ?//one.getUserName().equals(two.getUserName() //類似等價(jià) System.out.println("用戶名不一致"); } // 判斷密碼是否為空，是否一致 if(one.getPassword()==(two.getPassword())) { System.out.println("密碼為空"); } else if(!(one.getPassword()==(two.getPassword()))){ System.out.println("密碼不一致"); } return str;}}class User{ //定義屬性用戶名、密碼 private String username; private int password; public String getUserName() { return username; } public void setUserName(String username) { this.username = username; } public int getPassword() { return password; } public void setPassword(int password) { this.password = password;} public void print() { System.out.println("用戶名"+getUserName()); System.out.println("密碼"+getPassword()); } }?class Test{? ? // 測(cè)試方法 public static void main(String[] args) {? ? ?//實(shí)例化對(duì)象，調(diào)用相關(guān)方法實(shí)現(xiàn)運(yùn)行效果 User one=new User(); User two=new User(); one.setUserName("Lucy"); one.setPassword(123456); one.print(); two.setUserName("Mike"); two.setPassword(123456); two.print(); System.out.println("================="); userManager aaa=new userManager (); System.out.println(aaa.checkUser( one, two));? ? }}