java - 列表迭代器仅返回最后一行

Question

Iterator<Account> entitiesItr = entities.iterator();
List<AccountSync> accountsList = new ArrayList<AccountSync>();
AccountSync accountsync = new AccountSync();
while (entitiesItr.hasNext()) {
    Account account = (Account) entitiesItr.next();
    accountsync.setAccountName(account.getName());
    accountsList.add(accountsync);
    System.out.println("1st-name->"+account.getName());
}

Iterator<AccountSync> it = accountsList.iterator();
while (it.hasNext()) {
    AccountSync accountSync2 = (AccountSync) it.next();
    System.out.println("2nd-name->"+accountSync2.getAccountName());
        }

输出:

1st-name->Sun
1st-name->Oracle
1st-name->google
...
1st-name->Yahoo



2nd-name->Yahoo
2nd-name->Yahoo
2nd-name->Yahoo
2nd-name->Yahoo
....50 times

2nd-name-> 仅打印最后一行 50 次，而 1st-name-> 则打印全部 50 行。为什么会发生这种情况？

Answer 1

这是因为第一个循环不断覆盖相同的AccountSync。 试试这个方法:

AccountSync accountsync;
while (entitiesItr.hasNext()) {
    accountsync = new AccountSync();
    Account account = (Account) entitiesItr.next();
    accountsync.setAccountName(account.getName());
    accountsList.add(accountsync);
    System.out.println("1st-name->"+account.getName());
}

在这种情况下，每个实体都将正确拥有自己的 AccountSync 实例。