java.lang.IllegalStateException：无法执行此操作，因为连接池已关闭 [英] java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed
问题描述
我在自己的数据库框架中遇到了这个问题。我已经在StackOverflow中搜索了此问题，并尝试了许多提及的方法，但是此问题尚未解决。它在单线程中运行良好，当我尝试更新列表项时，该问题通常出现在App Widget中。
I met this problem in my own db framework. I have searched this problem in StackOverflow and tried many methods as mentioned, but this problem has not been solved. It worked well in single thread, the problem usually occor in App Widget, when I try to update the list items.
这里是解释：
1。这是用来获取SQLiteDatabase对象的SQLiteOpenHelper，如您所见，它是单例的：
1.this is the SQLiteOpenHelper used to get SQLiteDatabase object, as you see it's singleton:
public class PalmDB extends SQLiteOpenHelper {
public static PalmDB getInstance(final Context context){
if (sInstance == null){
synchronized (PalmDB.class) {
if (sInstance == null) {
sInstance = new PalmDB(context.getApplicationContext());
}
}
}
return sInstance;
}
}
2.Next是用于查询和保存的商店数据到数据库。它是抽象的：
2.Next is the store used to query and save data to database. It is abstract:
public abstract class BaseStore<T extends Model> {
private PalmDB mPalmDatabase = null;
@SuppressWarnings("unchecked")
public BaseStore(Context context) {
this.mPalmDatabase = PalmDB.getInstance(context);
}
protected SQLiteDatabase getWritableDatabase() {
return mPalmDatabase.getWritableDatabase();
}
protected synchronized void closeCursor(Cursor cursor) {
if (cursor == null || cursor.isClosed()) return;
try {
cursor.close();
} catch (Exception e){
LogUtils.d("Couldn't close cursor correctly");
}
}
public synchronized List<T> get(String whereSQL, String orderSQL, Status status, boolean exclude) {
Cursor cursor = null;
List<T> models = null;
SQLiteDatabase database = getWritableDatabase();
try {
cursor = database.rawQuery(" SELECT * FROM " + tableName
+ " WHERE " + BaseSchema.USER_ID + " = " + userId
+ (TextUtils.isEmpty(whereSQL) ? "" : " AND " + whereSQL)
+ (status == null ? "" : " AND " + BaseSchema.STATUS + (exclude ? " != " : " = ") + status.id)
+ (TextUtils.isEmpty(orderSQL) ? "" : " ORDER BY " + orderSQL),
new String[]{});
models = getList(cursor);
} finally {
closeCursor(cursor);
}
return models;
}
protected synchronized List<T> getList(Cursor cursor){
LogUtils.d(this); // print the hash code of this object
LogUtils.d(Thread.currentThread());
List<T> models = new LinkedList<>();
if (cursor != null && !cursor.isClosed() && cursor.moveToFirst()){ // exception here
do {
models.add(getModel(cursor));
} while (cursor.moveToNext());
} else if (cursor != null && cursor.isClosed()) {
LogUtils.e("cursor is closed : " + cursor);
}
return models;
}
private T getModel(Cursor cursor) {
T model = StoreHelper.getBaseModel(cursor, entityClass);
fillModel(model, cursor);
return model;
}
3。然后我将此类覆盖具体的对象。如您所见，它也是单例的：
3.Then I override this class for concrete object like this. As you can see that it is also singleton:
public class MindSnaggingStore extends BaseStore<MindSnagging> {
private static MindSnaggingStore sInstance = null;
public static MindSnaggingStore getInstance(Context context){
if (sInstance == null){
synchronized (MindSnaggingStore.class) {
if (sInstance == null) {
sInstance = new MindSnaggingStore(context.getApplicationContext());
}
}
}
return sInstance;
}
private MindSnaggingStore(Context context) {
super(context);
}
}
在活动和片段中效果很好，但是当我将其包含在App Widget中。当我尝试删除任何实体（通常两次）时，它崩溃了。
It worked fine in activities and fragments, but when I include it in App Widget. When I try to remove any entities, usually twice, then it crashed.
这里是个例外：
02-05 20:01:58.497 19317-19330/? E/AndroidRuntime: FATAL EXCEPTION: Binder:19317_1
Process: me.shouheng.notepal, PID: 19317
java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed.
at android.database.sqlite.SQLiteConnectionPool.throwIfClosedLocked(SQLiteConnectionPool.java:962)
at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:599)
at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)
at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)
at android.database.sqlite.SQLiteSession.executeForCursorWindow(SQLiteSession.java:834)
at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:62)
at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:143)
at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:132)
at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:219)
at android.database.AbstractCursor.moveToFirst(AbstractCursor.java:258)
at me.shouheng.notepal.provider.BaseStore.getList(BaseStore.java:330)
at me.shouheng.notepal.provider.BaseStore.get(BaseStore.java:127)
at me.shouheng.notepal.provider.BaseStore.get(BaseStore.java:101)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.getNotes(ListRemoteViewsFactory.java:72)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.setupModels(ListRemoteViewsFactory.java:63)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.onDataSetChanged(ListRemoteViewsFactory.java:86)
at android.widget.RemoteViewsService$RemoteViewsFactoryAdapter.onDataSetChanged(RemoteViewsService.java:142)
at com.android.internal.widget.IRemoteViewsFactory$Stub.onTransact(IRemoteViewsFactory.java:49)
at android.os.Binder.execTransact(Binder.java:565)
我确实将同步化的方法添加到重要方法中，并且db类是单例的，我想知道为什么我仍然遇到问题。
I did add the sychronized to important methods and the db class is singleton, I wonder why I still get the problem.
更多信息。下面是我的日志，我打印了线程，数据库和存储对象：
More information. Below is my log, I printed the thread, database and store objects:
02-05 22:41:53.119 15712-15712/me.shouheng.notepal D/colorful: ThemeDelegate fetched theme in 1 ms
02-05 22:41:53.305 3030-3149/system_process I/ActivityManager: Displayed me.shouheng.notepal/.activity.TrashedActivity: +235ms
02-05 22:41:53.648 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotebookStore@76f9b87
02-05 22:41:53.649 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:53.656 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:53.656 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:58.018 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:41)#<init> ] me.shouheng.notepal.provider.PalmDB@a34edfa
02-05 22:41:58.057 15712-15712/me.shouheng.notepal D/NotePal: [ (AppWidgetUtils.java:20)#NotifyAppWidgets ] Notifies AppWidget data changed for widgets [87, 85]
02-05 22:41:58.061 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotebookStore@76f9b87
02-05 22:41:58.062 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:58.071 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:58.072 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:58.155 15712-15712/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:51)#OnCreate ] Created widget 87
02-05 22:41:58.157 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:41)#<init> ] me.shouheng.notepal.provider.PalmDB@a34edfa
02-05 22:41:58.158 15712-15712/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:78)#GetMinds ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:58.158 15712-15712/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:79)#GetMinds ] Thread[main,5,main]
02-05 22:41:58.160 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:58.161 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:58.169 15712-15712/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:51)#OnCreate ] Created widget 85
02-05 22:41:58.171 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:58.172 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:58.172 15712-16198/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:85)#OnDataSetChanged ] onDataSetChanged widget 87
02-05 22:41:58.173 15712-16198/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:78)#GetMinds ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:58.173 15712-16198/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:79)#GetMinds ] Thread[Binder:15712_3,5,main]
02-05 22:41:58.174 15712-16198/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:58.175 15712-16198/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[Binder:15712_3,5,main]
02-05 22:41:58.177 15712-15725/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:85)#OnDataSetChanged ] onDataSetChanged widget 85
02-05 22:41:58.178 15712-15725/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:58.178 15712-15725/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[Binder:15712_1,5,main]
02-05 22:41:58.179 3030-4466/system_process W/InputMethodManagerService: Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@86f53ab attribute=null, token = android.os.BinderProxy@8dfbb89
02-05 22:41:58.483 15712-16191/me.shouheng.notepal D/OpenGLRenderer: endAllActiveAnimators on 0xc8ecfc00 (MenuPopupWindow$MenuDropDownListView) with handle 0xc8eb0540
02-05 22:41:58.933 3030-3485/system_process D/AudioService: Stream muted, skip playback
02-05 22:41:59.775 3030-3485/system_process D/AudioService: Stream muted, skip playback
02-05 22:41:59.804 15712-15712/me.shouheng.notepal D/NotePal: [ (AppWidgetUtils.java:20)#NotifyAppWidgets ] Notifies AppWidget data changed for widgets [87, 85]
02-05 22:41:59.807 15712-15725/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:85)#OnDataSetChanged ] onDataSetChanged widget 87
02-05 22:41:59.807 15712-16198/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:85)#OnDataSetChanged ] onDataSetChanged widget 85
02-05 22:41:59.808 15712-15725/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:78)#GetMinds ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:59.808 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotebookStore@76f9b87
02-05 22:41:59.808 15712-15725/me.shouheng.notepal D/NotePal: [ (ListRemoteViewsFactory.java:79)#GetMinds ] Thread[Binder:15712_1,5,main]
02-05 22:41:59.808 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:59.808 15712-16198/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:59.808 15712-15725/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.MindSnaggingStore@f341cfd
02-05 22:41:59.810 15712-16198/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[Binder:15712_3,5,main]
02-05 22:41:59.810 15712-15712/me.shouheng.notepal I/SQLiteConnectionPool: The connection pool for /data/user/0/me.shouheng.notepal/databases/NotePal.db has been closed but there are still 1 connections in use. They will be closed as they are released back to the pool.
02-05 22:41:59.811 15712-15725/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[Binder:15712_1,5,main]
02-05 22:41:59.828 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:327)#GetList ] me.shouheng.notepal.provider.NotesStore@f4252
02-05 22:41:59.829 15712-15712/me.shouheng.notepal D/NotePal: [ (BaseStore.java:328)#GetList ] Thread[main,5,main]
02-05 22:41:59.867 15712-15717/me.shouheng.notepal I/art: Do full code cache collection, code=97KB, data=125KB
02-05 22:41:59.868 15712-15717/me.shouheng.notepal I/art: Starting a blocking GC JitCodeCache
02-05 22:41:59.868 15712-15717/me.shouheng.notepal I/art: After code cache collection, code=79KB, data=87KB
02-05 22:41:59.899 3030-14418/system_process W/InputMethodManagerService: Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@9aae3c6 attribute=null, token = android.os.BinderProxy@8dfbb89
02-05 22:41:59.957 15712-15725/me.shouheng.notepal E/AndroidRuntime: FATAL EXCEPTION: Binder:15712_1
Process: me.shouheng.notepal, PID: 15712
java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed.
at android.database.sqlite.SQLiteConnectionPool.throwIfClosedLocked(SQLiteConnectionPool.java:962)
at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:599)
at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)
at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)
at android.database.sqlite.SQLiteSession.executeForCursorWindow(SQLiteSession.java:834)
at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:62)
at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:143)
at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:132)
at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:219)
at android.database.AbstractCursor.moveToFirst(AbstractCursor.java:258)
at me.shouheng.notepal.provider.BaseStore.getList(BaseStore.java:330)
at me.shouheng.notepal.provider.BaseStore.get(BaseStore.java:127)
at me.shouheng.notepal.provider.BaseStore.get(BaseStore.java:101)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.getMinds(ListRemoteViewsFactory.java:80)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.setupModels(ListRemoteViewsFactory.java:65)
at me.shouheng.notepal.widget.desktop.ListRemoteViewsFactory.onDataSetChanged(ListRemoteViewsFactory.java:86)
at android.widget.RemoteViewsService$RemoteViewsFactoryAdapter.onDataSetChanged(RemoteViewsService.java:142)
at com.android.internal.widget.IRemoteViewsFactory$Stub.onTransact(IRemoteViewsFactory.java:49)
at android.os.Binder.execTransact(Binder.java:565)
推荐答案
我的问题解决了。原因很简单，我只是在一个地方使用了SQLiteDatabase.close（），所以它崩溃了。
即便如此，对于我来说，这仍然是一个很好的机会，以了解有关Android数据库连接池的更多信息。这对我解决这个问题很有用。
My problem is solved. The reason is rather simple, it's just in one place that I used the SQLiteDatabase.close() so it crashed. Even so, it's still a good opportunity for me to learn more about Android database connection pool. Here is something that useful for me to solve this problem.
我们分别调用SQLiteOpenHelper.getWrteableDatabase（）和SQLiteOpenHelper.getReadableDatabase（）来获取SQLiteDatabase对象。逻辑非常简单，如果SQLiteDatabase对象已经用于业务，它将返回它，否则它将创建一个新对象并为业务做准备，然后返回它。因此，这意味着，如果SQLiteOpenHelper为单例，则SQLiteDatabase对象也为单例。如果我们调用SQLiteOpenHelper.close（）或SQLiteDatabase.close（），它们都将调用SQLiteDatabase.close（）。在SQLiteDatabase.close（）中，它将判断当前引用号，如果释放所有引用，则将关闭SQLiteConnectionPool。
We call SQLiteOpenHelper.getWrteableDatabase() and SQLiteOpenHelper.getReadableDatabase() to get the SQLiteDatabase object. The logic is rather simple, if the SQLiteDatabase object is already for business, it will return it, else it will create a new one and prepare for business and then return it. So, that means, if the SQLiteOpenHelper is singleton, the SQLiteDatabase object is singleton too. If we call the SQLiteOpenHelper.close() or SQLiteDatabase.close(), they will all call SQLiteDatabase.close(). In SQLiteDatabase.close(), it will judge current references number, if all the references released, the SQLiteConnectionPool will be closed.
因此，这意味着，如果所有Store（用于存储和查询db中的数据）对象都使用相同的SQLiteDatabaseHelper，则它们也将使用相同的SQLiteDatabase。如果我在一个Store对象中关闭了SQLiteDatabase，它将影响另一个Store对象。即使我在一个Store方法中添加了sychronized关键字，它也只会将方法锁定在同一对象中。这是导致此异常的真正原因。
So, that means, if all the Store (used to store and query data from db) objects use the same SQLiteDatabaseHelper, they will use the same SQLiteDatabase too. If I closed SQLiteDatabase in one Store object, it will affect another Store object. Even I added the sychronized keyword in one Store methods, it will only lock methods in the same object. That is the real reason caused this exception.
然后我删除了SQLiteDatabase.close（）逻辑，它工作正常。
Then I removed the SQLiteDatabase.close() logic, it worked fine.
但是，如果我要关闭SQLiteDatabase。我为我的案件找到了一种方法。 OpenHelperManager用于计算当前连接数，如果该数为零，则可以关闭数据库连接。
But, what if I want to close the SQLiteDatabase. I found out one way for my case. The OpenHelperManager is used to calculate current connections number and if the number is zero, then it can close the db connection.
public class OpenHelperManager {
@SuppressLint("StaticFieldLeak")
private static boolean isClosed = false;
private static int instanceCount = 0;
public static synchronized void releaseHelper(PalmDB helper) {
instanceCount--;
LogUtils.e(String.format("releasing helper %s, instance count = %s", helper, instanceCount));
if (instanceCount <= 0) {
if (helper != null) {
LogUtils.e(String.format("zero instances, closing helper %s", helper));
helper.close();
isClosed = true;
}
if (instanceCount < 0) {
LogUtils.e(String.format("too many calls to release helper, instance count = %s", instanceCount));
}
}
}
public static synchronized void requireConnection() {
isClosed = false;
instanceCount++;
}
public static boolean isClosed() {
return isClosed;
}
}
PalmDB在此处扩展了SQLiteOpenHelper：
Here, the PalmDB extends SQLiteOpenHelper:
public class PalmDB extends SQLiteOpenHelper {
// ...
}
在存储对象中：
protected SQLiteDatabase getWritableDatabase() {
OpenHelperManager.requireConnection();
return mPalmDatabase.getWritableDatabase();
}
protected void closeDatabase(SQLiteDatabase database) {
OpenHelperManager.releaseHelper(mPalmDatabase);
}
我使用getWritableDatabase（）方法获取SQLiteDatabase，同时增加OpenHelperManager中实例的数量。添加use closeDatabase（）方法而不是SQLiteDatabase.close（）来关闭数据库。在closeDatabase（）方法中，我调用了OpenHelperManager.releaseHelper（mPalmDatabase），它将减少OpenHelperManager中实例的数量。如果实例的计数为零，则关闭SQLiteOpenHelper，这将关闭SQLiteDatabse对象。对于我的情况来说效果很好。您还可以使用一些原子类，例如AtomicInteger来计算计数。
I use getWritableDatabase() method to get SQLiteDatabase, and at the same time increase the count of instance in OpenHelperManager. Add use closeDatabase() method instead of SQLiteDatabase.close() to close database. In closeDatabase() method, I called OpenHelperManager.releaseHelper(mPalmDatabase), which will decrease the count of instance in OpenHelperManager. If the count of instance is zero, then close the SQLiteOpenHelper, that will close SQLiteDatabse object. It worked fine for my case. You may also use some atomic classes like AtomicInteger to calculate the count.
这是我的问题的答案，希望对您有所帮助。
That is the answer for my problem, hope it helps for you.
这篇关于java.lang.IllegalStateException：无法执行此操作，因为连接池已关闭的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
