我尝试使用JaxB将我创建的对象编组到XML中。我想要的是创建一个列表，然后将其打印到文件中，然后创建一个新的列表，并将其打印到同一个文件中，但每次我这样做都会重写第一个。我希望最终的XML文件看起来像我只有一个大的对象列表。我会这样做，但有这么多，我很快就最大化了我的堆大小。
所以，我的main创建了一堆线程，每个线程遍历它接收到的对象列表，并在每个对象上调用create_Log。一旦完成，它就调用printToFile，这是它将列表编组到文件的地方。

public class LogThread implements Runnable {
//private Thread myThread;
private Log_Message message = null;
private LinkedList<Log_Message> lmList = null;
LogServer Log = null;
private String Username = null;

public LogThread(LinkedList<Log_Message> lmList){
    this.lmList = lmList;
}

public void run(){
    //System.out.println("thread running");
    LogServer Log = new LogServer();
    //create iterator for list
    final ListIterator<Log_Message> listIterator = lmList.listIterator();

    while(listIterator.hasNext()){
        message = listIterator.next();
        CountTrans.addTransNumber(message.TransactionNumber);
        Username = message.input[2];
        Log.create_Log(message.input, message.TransactionNumber, message.Message, message.CMD);
    }
    Log.printToFile();
    init_LogServer.threadCount--;
    init_LogServer.doneList();
    init_LogServer.doneUser();
    System.out.println("Thread "+ Thread.currentThread().getId() +" Completed user: "+ Username+"... Number of Users Complete: " + init_LogServer.getUsersComplete());
    //Thread.interrupt();
}
}

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上面的代码调用下面的函数create_Log来构建一个新的对象，该对象是从给定的XSD生成的（SystemEventType，QuoteServerType. etc）.这些对象都使用下面的函数添加到ArrayList中，并附加到Root对象。一旦LogThread循环完成，它就会调用printToFile，它会从Root对象中获取列表并将其编组到文件中......删除已经存在的内容。如何我可以把它添加到同一个文件中，而不需要重写，也不需要在堆中创建一个主列表吗？

public class LogServer {
public log Root = null;
public static String fileName = "LogFile.xml";
public static File XMLfile = new File(fileName);

public LogServer(){
    this.Root = new log();
}
//output LogFile.xml
public synchronized void printToFile(){
    System.out.println("Printing XML");
    //write to xml file
    try {
        init_LogServer.marshaller.marshal(Root,XMLfile);
    } catch (JAXBException e) {
        e.printStackTrace();
    }
    System.out.println("Done Printing XML");
}

private BigDecimal ConvertStringtoBD(String input){
    DecimalFormatSymbols symbols = new DecimalFormatSymbols();
    symbols.setGroupingSeparator(',');
    symbols.setDecimalSeparator('.');
    String pattern = "#,##0.0#";
    DecimalFormat decimalFormat = new DecimalFormat(pattern, symbols);
    decimalFormat.setParseBigDecimal(true);
    // parse the string
    BigDecimal bigDecimal = new BigDecimal("0");
    try {
        bigDecimal = (BigDecimal) decimalFormat.parse(input);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return bigDecimal;
}

public QuoteServerType Log_Quote(String[] input, int TransactionNumber){
    BigDecimal quote = ConvertStringtoBD(input[4]);
    BigInteger TransNumber = BigInteger.valueOf(TransactionNumber);
    BigInteger ServerTimeStamp = new BigInteger(input[6]);
    Date date = new Date();
    long timestamp = date.getTime();
    ObjectFactory factory = new ObjectFactory();
    QuoteServerType quoteCall = factory.createQuoteServerType();

    quoteCall.setTimestamp(timestamp);
    quoteCall.setServer(input[8]);
    quoteCall.setTransactionNum(TransNumber);
    quoteCall.setPrice(quote);
    quoteCall.setStockSymbol(input[3]);
    quoteCall.setUsername(input[2]);
    quoteCall.setQuoteServerTime(ServerTimeStamp);
    quoteCall.setCryptokey(input[7]);

    return quoteCall;
}
public SystemEventType Log_SystemEvent(String[] input, int TransactionNumber, CommandType CMD){
    BigInteger TransNumber = BigInteger.valueOf(TransactionNumber);
    Date date = new Date();
    long timestamp = date.getTime();
    ObjectFactory factory = new ObjectFactory();
    SystemEventType SysEvent = factory.createSystemEventType();

    SysEvent.setTimestamp(timestamp);
    SysEvent.setServer(input[8]);
    SysEvent.setTransactionNum(TransNumber);
    SysEvent.setCommand(CMD);
    SysEvent.setFilename(fileName);

    return SysEvent;
}

public void create_Log(String[] input, int TransactionNumber, String Message, CommandType Command){
    switch(Command.toString()){
    case "QUOTE":  //Quote_Log
        QuoteServerType quote_QuoteType = Log_Quote(input,TransactionNumber);
        Root.getUserCommandOrQuoteServerOrAccountTransaction().add(quote_QuoteType);
        break;

    case "QUOTE_CACHED":
        SystemEventType Quote_Cached_SysType = Log_SystemEvent(input, TransactionNumber, CommandType.QUOTE);
        Root.getUserCommandOrQuoteServerOrAccountTransaction().add(Quote_Cached_SysType);
        break;

}
}

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编辑：下面是如何将对象添加到ArrayList的代码

public List<Object> getUserCommandOrQuoteServerOrAccountTransaction() {
    if (userCommandOrQuoteServerOrAccountTransaction == null) {
        userCommandOrQuoteServerOrAccountTransaction = new ArrayList<Object>();
    }
    return this.userCommandOrQuoteServerOrAccountTransaction;
}

型