Java ==!= && ||运营商?
问题描述:
我的代码有问题。此代码应检查登录名和密码。问题是else if语句显示错误的输出。例如,当我输入用户名== admin和密码== 1234时,它显示的用户名不正确。Java ==!= && ||运营商?
import java.io.*;
public class login
{
public static void main(String [] args) throws IOException
{
String username = "admin";
String password = "123";
BufferedReader inData = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter username : ");
username = inData.readLine();
System.out.print("Enter password : ");
password = inData.readLine();
if((username == "admin") && (password == "123"))
{
System.out.println("Welcome " + username + "\n*** Login Sucessfully ***" + "\n*** Access Granted ***");
}
else if((username != "admin") && (password == "123"))
{
System.out.println("Sorry, username is incorrect!\n*** Access Denied ***");
}
else if((username == "admin") && (password != "123"))
{
System.out.println("Sorry, password is incorrect!\n*** Access Denied ***");
}
else if((username != "admin") && (password != "123"))
{
System.out.println("Sorry, username and password is incorrect!\n*** Access Denied ***");
}
}
}
答
.equals()
.equals()
方法用于在这种情况下比较字符串。例如username.equals("admin")
,它比较变量用户名的值和值“admin”,这里都是字符串
当你比较字符串时你明白==和equals的区别吗? – Li357
@Kero Kero ==用于比较用于比较String的int或float值(数字)和.equals()方法。 – yash
@AndrewL。哦,以前从来不知道。现在我明白了==和.equals之间 –