与App Engine兼容的JDBC连接池 [英] JDBC connection pool compatible with App Engine

问题描述

注意：我知道此线程，但它是相当老，而且，解决方案不适合我。

我正在使用App Engine和Cloud SQL，我想共享应用程序当前所有用户之间的开放连接池。我尝试了几个连接池实现，并且它们都与本地开发服务器完美协作，但是，当部署到云时，它们会失败。我想这是因为App Engine的受限沙箱环境。有人知道JDBC连接池在App Engine上工作吗？

Apache Commons DBCP

  ... 
导致：java.lang.NoClassDefFoundError：无法初始化com.google.appengine类org.apache.commons.dbcp2.PoolableConnection 
 .runtime.Request.process -a49d46300800d0ca（Request.java）
 at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject（PoolableConnectionFactory.java:254）
 at org.apache.commons.dbcp2.BasicDataSource （BasicDataSource.java:2162）
 at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory（BasicDataSource.java:2148）
 at org.apache.commons.dbcp2.BasicDataSource.createDataSource（BasicDataSource的.java：1903）
在org.apache.commons.dbcp2.BasicDataSource $ PaGetConnection.run（BasicDataSource.java:2267）
在org.apache.commons.dbcp2.BasicDataSource $ PaGetConnection.run（的BasicDataSource .java：2263）$ java.util.AccessController.doPr中的
在（org.apache.commons.dbcp2.BasicDataSource.getConnection（BasicDataSource.java:1404）
 ... 
  

Tomcat JDBC连接池

  ... 
导致：java.lang.SecurityException：无法获取类org.apache.tomcat.jdbc.pool.DataSource的成员
 
 ... 
 
导致：java.lang.reflect.InvocationTargetException 
 at sun.reflect.GeneratedMethodAccessor9.invoke（Unknown Source）
 at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）
 at java.lang.reflect.Method.invoke（Method.java:606）
 ... 45 more 
导致：java.lang.NoClassDefFoundError：javax / management / MalformedObjectNameException 
在java.lang.Class.getDeclaredMethods0（本地方法）$ b $在java.lang.Class.privateGetDeclaredMethods（Class.java:2517）
 ... 45更多
由java导致。 lang.ClassNotFoundException：javax.management.MalformedObjectName例外
 ... 45 more 
  

HikariCP

  ... 
 java.security.AccessControlException：访问被拒绝（java.lang.RuntimePermissionmodifyThreadGroup）
。在java.security.AccessControlContext.checkPermission（AccessControlContext.java:375）
在java.security.AccessController.checkPermission（AccessController.java:565）
在java.lang.SecurityManager.checkPermission（安全管理器.java：549）
 at java.lang.ThreadGroup.checkAccess（ThreadGroup.java:315）
 at java.lang.Thread.init（Thread.java:378）
 at java。 lang.Thread<初始化>（Thread.java:527）
。在com.zaxxer.hikari.util.DefaultThreadFactory.newThread（DefaultThreadFactory.java:32）
。在java.util.concurrent.ThreadPoolExecutor中$工人<初始化>（ThreadPoolExecutor.java:591）
。在java.util.concurrent.ThreadPoolExecutor.addWorker（ThreadPoolExecutor.java:922）
。在java.util.concurrent.ThreadPoolExecutor.ensurePrestart（ ThreadPoolExecutor.j ava：1591）
 at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute（ScheduledThreadPoolExecutor.java:305）
 at java.util.concurrent.ScheduledThreadPoolExecutor.scheduleAtFixedRate（ScheduledThreadPoolExecutor.java:542）
在com.zaxxer.hikari.pool.HikariPool<初始化>（HikariPool.java:161）
。在com.zaxxer.hikari.pool.HikariPool<初始化>（HikariPool.java:114）
 at com.zaxxer.hikari.HikariDataSource.getConnection（HikariDataSource.java:102）
 ... 
  

Vibur DBCP

  ... 
引起：java。 security.AccessControlException：访问被拒绝（java.lang.RuntimePermissionmodifyThreadGroup）$ b $在java.security.AccessControlContext.checkPermission（AccessControlContext.java:375）$ b $在java.security.AccessController.checkPermission AccessController.java:565）
在java.lang.SecurityManager.checkPermission（SecurityManager.java:549）
在java.lang.ThreadGroup.checkAccess（ThreadGroup.java： （Thread.java:478）
 at java.lang.Thread.init（Thread.java:378）
 at java.lang.Thread。< init>（Thread.java:448）
 at org。 < init>（SamplingPoolReducer.java:78）
 at org.vibur.dbcp.pool.PoolOperations $ PoolReducer。< init>（PoolOperations.java:88）
在org.vibur.dbcp.pool.PoolOperations $ PoolReducer。< init>（PoolOperations.java:86）
 at org.vibur.dbcp.pool.PoolOperations。< init>（PoolOperations.java:79 ）
 at org.vibur.dbcp.ViburDBCPDataSource.start（ViburDBCPDataSource.java:197）
 .... 
  

c3p0

  ... 
引起：java.security.AccessControlException：访问被拒绝（ java.lang.RuntimePermission modifyThreadGroup）
在java.security.AccessControlContext.checkPermission（AccessControlContext.java:375）
在java.security.AccessController .checkPermission（AccessController.java:565）
位于java.lang.SecurityManager.checkPermission（SecurityMana ger.java:549）
 at java.lang.ThreadGroup.checkAccess（ThreadGroup.java:315）
 at java.lang.Thread.init（Thread.java:378）
 at java .lang.Thread。< init>（Thread.java:487）
 ... 
  

https://github.com/kennberg/appengine- java-connection-pool

请注意，一旦请求过多，连接池就非常必要，因为每个实例的挂起连接数量有限制。重新使用连接有助于保持在限制之下。

Note: I know about this thread but it is quite old and moreover, the solution did not work for me.

I am using App Engine along with Cloud SQL and I would like to share a pool of open connections between all of the application's current users. I have tried several connection pool implementations and they all work perfectly with the local development server, however, when deployed to the cloud, they fail. I suppose that the reason is App Engine's restricted "sandbox" environment. Does anyone know about JDBC connection pool working on App Engine?

Apache Commons DBCP

...
Caused by: java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.dbcp2.PoolableConnection
at com.google.appengine.runtime.Request.process-a49d46300800d0ca(Request.java)
at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:254)
at org.apache.commons.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2162)
at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2148)
at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1903)
at org.apache.commons.dbcp2.BasicDataSource$PaGetConnection.run(BasicDataSource.java:2267)
at org.apache.commons.dbcp2.BasicDataSource$PaGetConnection.run(BasicDataSource.java:2263)
at java.security.AccessController.doPrivileged(AccessController.java:63)
at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1404)
...

Tomcat JDBC Connection Pool

...
Caused by: java.lang.SecurityException: Unable to get members for class org.apache.tomcat.jdbc.pool.DataSource

...

Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
... 45 more
Caused by: java.lang.NoClassDefFoundError: javax/management/MalformedObjectNameException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2517)
... 45 more
Caused by: java.lang.ClassNotFoundException: javax.management.MalformedObjectNameException
... 45 more

HikariCP

...
java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "modifyThreadGroup")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:375)
at java.security.AccessController.checkPermission(AccessController.java:565)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
at java.lang.ThreadGroup.checkAccess(ThreadGroup.java:315)
at java.lang.Thread.init(Thread.java:378)
at java.lang.Thread.<init>(Thread.java:527)
at com.zaxxer.hikari.util.DefaultThreadFactory.newThread(DefaultThreadFactory.java:32)
at java.util.concurrent.ThreadPoolExecutor$Worker.<init>(ThreadPoolExecutor.java:591)
at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:922)
at java.util.concurrent.ThreadPoolExecutor.ensurePrestart(ThreadPoolExecutor.java:1591)
at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:305)
at java.util.concurrent.ScheduledThreadPoolExecutor.scheduleAtFixedRate(ScheduledThreadPoolExecutor.java:542)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:161)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:114)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:102)
...

Vibur DBCP

...
Caused by: java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "modifyThreadGroup")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:375)
at java.security.AccessController.checkPermission(AccessController.java:565)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
at java.lang.ThreadGroup.checkAccess(ThreadGroup.java:315)
at java.lang.Thread.init(Thread.java:378)
at java.lang.Thread.<init>(Thread.java:448)
at org.vibur.objectpool.reducer.SamplingPoolReducer.<init>(SamplingPoolReducer.java:78)
at org.vibur.dbcp.pool.PoolOperations$PoolReducer.<init>(PoolOperations.java:88)
at org.vibur.dbcp.pool.PoolOperations$PoolReducer.<init>(PoolOperations.java:86)
at org.vibur.dbcp.pool.PoolOperations.<init>(PoolOperations.java:79)
at org.vibur.dbcp.ViburDBCPDataSource.start(ViburDBCPDataSource.java:197)
....

c3p0

...
Caused by: java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "modifyThreadGroup")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:375)
at java.security.AccessController.checkPermission(AccessController.java:565)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
at java.lang.ThreadGroup.checkAccess(ThreadGroup.java:315)
at java.lang.Thread.init(Thread.java:378)
at java.lang.Thread.<init>(Thread.java:487)
...

解决方案

I had to use Tomcat DBCP 1.4 (older version), because of the GAE frontend not allowing threads to live outside of request scope. Here's an example project: https://github.com/kennberg/appengine-java-connection-pool

Note that the connection pool is necessary once you have too many requests, because there is a limit on number of pending connections per instance. Re-using connections helps stay under the limit.

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