嗯,我已經閱讀了其他帖子,無法解決我的問題。我的ManagedBean中有一個dataTable(JSF)綁定。我有選擇的要素的列表,我想刪除這個元素,請參閱:嘗試從列表中刪除元素時出現ConcurrentModificationException
public void removeSelected() {
for (Map.Entry<Integer, Boolean> entry : registrosSelecionados.entrySet()){
if (entry.getValue() == true){
int id = entry.getKey();
Iterator<Bean> it = beans.iterator();
while(it.hasNext()){
Bean b = it.next();
if (b.getId().equals(id)){
setBean(b);
deletar();
}
}
}
}
}
我上面調用另一個名爲法「deletar()」方法,請參閱:
public void deletar() {
try {
//Se o bean for nulo então capturamos o bean selecionado no DataTable, se este existir
if (bean == null){
if (dataTable == null){
throw new RuntimeException("O bean é nulo e não há dataTable vinculado ao ManagedBean. A deleção será abortada");
}
bean = (Bean) dataTable.getRowData();
}
beforeRemove();
getBoPadrao().delete((AbstractBean) bean);
addInfoMessage("Registro deletado com sucesso");
beans.remove(bean);
bean = null;
afterRemove();
} catch (BOException e) {
addErrorMessage(e.getMessage());
FacesContext.getCurrentInstance().validationFailed();
} catch (Exception e) {
e.printStackTrace();
logger.error((new StringBuilder()).append("Erro ao deletar: ")
.append(e.getMessage()).toString());
FacesContext.getCurrentInstance().validationFailed();
addErrorMessage((new StringBuilder()).append("Erro ao deletar. ")
.append(e.getMessage()).toString());
}
}
的豆是從刪除數據庫但當嘗試從「目錄」中刪除我得到錯誤:
Jan 31, 2015 5:38:32 PM com.sun.faces.context.AjaxExceptionHandlerImpl handlePartialResponseError
Grave: java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
at java.util.ArrayList$Itr.next(ArrayList.java:831)
at br.com.jwebbuild.mb.BasicCrudMBImpl.removeSelected(BasicCrudMBImpl.java:226)
編輯1
我試着編輯我的deletar()方法把一個迭代器刪除元素,但沒有工作,錯誤繼續。
public void deletar() {
try {
//Se o bean for nulo então capturamos o bean selecionado no DataTable, se este existir
if (bean == null){
if (dataTable == null){
throw new RuntimeException("O bean é nulo e não há dataTable vinculado ao ManagedBean. A deleção será abortada");
}
bean = (Bean) dataTable.getRowData();
}
beforeRemove();
getBoPadrao().delete((AbstractBean) bean);
addInfoMessage("Registro deletado com sucesso");
Iterator<Bean> it = beans.iterator();
while (it.hasNext()) {
Bean b = it.next();
if (b.equals(bean)) {
it.remove();
}
}
bean = null;
afterRemove();
這是不相關的JSF反正。它是Java SE。迭代該集合時,無法刪除集合的元素。相反,該功能是通過迭代器的刪除方法合併的。正如答案所示,你應該在這種情況下使用迭代器的刪除方法。 – Tiny 2015-02-01 04:12:43
「*請注意,Iterator.remove是在迭代過程中修改集合的唯一安全方法;如果在迭代過程中以任何其他方式修改了基礎集合,則行爲未指定*」http://docs.oracle.com .com/javase/tutorial/collections/interfaces/collection.html – Tiny 2015-02-01 04:13:56