我正在使用该程序将数据从数据库发送到Excel文件。 它在开始时工作正常,然后变得越来越慢,最终它耗尽内存和下列错误代码:“java.lang.OutOfMemoryError:Java heap space ...”。为什么我的程序变得越来越慢?
该问题可以通过添加jvm堆sapce来解决。但问题是它花费了太多的时间来运行该程序。
几分钟后,它完成了一个4秒的循环,可以在开始时以0.5秒结束。我找不到解决方案使其始终以特定的速度运行。
这是我的代码问题吗?
对此有任何线索?
下面是代码:
public void addAnswerRow(List<FinalUsers> finalUsersList,WritableWorkbook book){
if (finalUsersList.size() >0) {
try {
WritableSheet sheet = book.createSheet("Answer", 0);
int colCount = 0;
sheet.addCell(new Label(colCount++,0,"Number"));
sheet.addCell(new Label(colCount++,0,"SchoolNumber"));
sheet.addCell(new Label(colCount++,0,"District"));
sheet.addCell(new Label(colCount++,0,"SchoolName"));
sheet.setColumnView(1, 15);
sheet.setColumnView(3, 25);
List<Elements> elementsList = this.elementsManager.getObjectElementsByEduTypeAndQuestionnaireType(finalUsersList.get(0).getEducationType().getId(), this.getQuestionnaireByFinalUsersType(finalUsersList.get(0).getFinalUsersType().getId()));
Collections.sort(elementsList, new Comparator<Elements>(){
public int compare(Elements o1, Elements o2) {
for(int i=0; i< (o1.getItemNO().length()>o2.getItemNO().length()? o2.getItemNO().length(): o1.getItemNO().length());i++){
if (CommonFun.isNumberic(o1.getItemNO().substring(0, o1.getItemNO().length()>3? 4: o1.getItemNO().length()-1)) && !CommonFun.isNumberic(o2.getItemNO().substring(0, o2.getItemNO().length()>3? 4: o2.getItemNO().length()-1))){
return 1;
}
if (!CommonFun.isNumberic(o1.getItemNO().substring(0, o1.getItemNO().length()>3? 4: o1.getItemNO().length()-1)) && CommonFun.isNumberic(o2.getItemNO().substring(0,o2.getItemNO().length()>3? 4:o2.getItemNO().length()-1))){
return -1;
}
if (o1.getItemNO().charAt(i)!=o2.getItemNO().charAt(i)){
return o1.getItemNO().charAt(i)-o2.getItemNO().charAt(i);
}
}
return o1.getItemNO().length()> o2.getItemNO().length()? 1:-1;
}});
for (Elements elements : elementsList){
sheet.addCell(new Label(colCount++,0,this.getTitlePre(finalUsersList.get(0).getFinalUsersType().getId(), finalUsersList.get(0).getEducationType().getId())+elements.getItemNO()+elements.getItem().getStem()));
}
int sheetRowCount =1;
int sheetColCount =0;
for(FinalUsers finalUsers : finalUsersList){
sheetColCount =0;
sheet.addCell(new Label(sheetColCount++,sheetRowCount,String.valueOf(sheetRowCount)));
sheet.addCell(new Label(sheetColCount++,sheetRowCount,finalUsers.getSchool().getSchoolNumber()));
sheet.addCell(new Label(sheetColCount++,sheetRowCount,finalUsers.getSchool().getDistrict().getDistrictNumber().toString().trim()));
sheet.addCell(new Label(sheetColCount++,sheetRowCount,finalUsers.getSchool().getName()));
List<AnswerLog> answerLogList = this.answerLogManager.getAnswerLogByFinalUsers(finalUsers.getId());
Map<String,String> answerMap = new HashMap<String,String>();
for(AnswerLog answerLog :answerLogList){
if (answerLog.getOptionsId() != null)
{
answerMap.put(answerLog.getElement().getItemNO(), this.getOptionsAnswer(answerLog.getOptionsId()));
}else if (answerLog.getBlanks()!= null){
answerMap.put(answerLog.getElement().getItemNO(), answerLog.getBlanks());
}else{
answerMap.put(answerLog.getElement().getItemNO(), answerLog.getSubjectiveItemContent());
}
}
for (Elements elements : elementsList){
sheet.addCell(new Label(sheetColCount++,sheetRowCount,null==answerMap.get(elements.getItemNO())?"0":answerMap.get(elements.getItemNO())));
}
sheetRowCount++;
}
book.write();
book.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (RowsExceededException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (WriteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}
你并不需要详细解释一下。例如,“我拿着两片都有一个共同的键(从下面的评论续)(studentId或东西??)并加入他们“或什么的。然后,我们可以推荐您使用合并排序来首先排序这些表格,使用磁盘空间,然后您可以在不使用大量内存的情况下遍历这两个表格...... – 2010-02-26 17:54:04