在Java中停止ArrayList的迭代

Question

我正在迭代一个ArrayList名为clientList的客户端,其中包含来自该类的客户端Client (user,pass)

ArrayList<Client> clientList= new ArrayList<Client>();

这是迭代.如果它找到给定的用户(用户)并且密码(pass)匹配,我想停止迭代:

            for (Client c : clientList) {
                userA = c.getUser();
                if (userA.equals(user)) {
                    passA = c.getPassword();
                    if (passA.equals(pass)) {
                        loginOK = true;
                        found= true;
                    }

我正在尝试以下(找到== false),但如果它没有在ArrayList上找到用户,它会被卡住:

        while (found == false) { /
            for (Client c : clientList) {
                userA = c.getUser();
                if (userA.equals(user)) {
                    passA = c.getPassword();
                    if (passA.equals(pass)) {
                        loginOK = true;
                        found= true;
                    }
                }
            }
        }

Answer 1

break找到值时,您应该退出循环.

for (something) {
   if (anotherThingIsFound) {
      break;
   }
}
//Execution will continue here when you break...

请注意,借助标签,也可以打破嵌套循环.例如

outer:
while (someCondition) {
   for (criteria) {
      if (somethingHappened) {
         break outer; 
      }
      if (anotherThingHashHappened) {
         break;
      }
   }
   //Execution will continue here if we execute the "normal" break.
}
//Execution will continue here when we execute "break outer;"

continue 也适用于标签.

Answer 2

为什么不break呢？

for (Client c : clientList) {
    userA = c.getUser();
    if (userA.equals(user)) {
        passA = c.getPassword();
        if (passA.equals(pass)) {
            loginOK = true;
            found = true;
            break;
        }
    }
}

(我假设你需要告诉获取到年底之间的差别发现有人和获取到底,不找人,你可能只需要一个变量虽然,而不是两个...)

有了您的while循环尝试,你会在整个列表迭代永远如果用户没有找到,并且即使用户被发现,它会遍历整个列表一次-因为你的for循环是内 while循环.while循环每次迭代只检查while条件.