java.util.NoSuchElementException 在 java 中使用迭代器
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java.util.NoSuchElementException using iterator in java
提问by Frederikkastrup
I'm trying to iterate through a list using the iterator over my list of Logs. The goal is to search for a logs which contains the same phonenumber, type and date as the new log
我正在尝试使用迭代器遍历我的日志列表来遍历列表。目标是搜索包含与新日志相同的电话号码、类型和日期的日志
However, I get a java.util.NoSuchElementException in my conditional statement. Does anyone know what might cause the problem?
但是，我在我的条件语句中得到了 java.util.NoSuchElementException。有谁知道可能导致问题的原因？
My code
我的代码
public void addLog(String phonenumber, String type, long date, int incoming, int outgoing)
{
//Check if log exists or else create it.
Log newLog = new Log(phonenumber, type, date, incoming, outgoing);
//Log exists
Boolean notExist = false;
//Iterator loop
Iterator<Log> iterator = logs.iterator();
while (iterator.hasNext())
{
//This is where get the exception
if (iterator.next().getPhonenumber() == phonenumber && iterator.next().getType() == type && iterator.next().getDate() == date)
{
updateLog(newLog, iterator.next().getId());
}
else
{
notExist = true;
}
}
if (notExist)
{
logs.add(newLog);
}
}
采纳答案by Sotirios Delimanolis
You are calling next()a bunch of times in one iteration forcing the Iteratorto move to an element that doesn't exist.
您next()在一次迭代中调用了很多次，迫使Iterator移动到不存在的元素。
Instead of
代替
if (iterator.next().getPhonenumber() == phonenumber && iterator.next().getType() == type && iterator.next().getDate() == date)
{
updateLog(newLog, iterator.next().getId());
...
Use
用
Log log = iterator.next();
if (log.getPhonenumber() == phonenumber && log.getType() == type && log.getDate() == date)
{
updateLog(newLog, log .getId());
...
Every time you call Iterator#next(), it moves the underlying cursor forward.
每次调用时Iterator#next()，它都会向前移动底层光标。
