[英]Is there any ssh client supporting java.nio.channels.SocketChannel?
[英]java.lang.Object cannot be cast to java.nio.channels.SocketChannel
在我的应用程序中,我有以下代码:
SamplePoolableObjectFactory factory = new SamplePoolableObjectFactory();
this.pool = new SampleObjectPool(factory);
.....
SocketChannel channel = null;
try {
channel = (SocketChannel) this.pool.borrowObject();
....
}
我有这个错误:
Unable to borrow socket from pool java.lang.ClassCastException: java.lang.Object cannot be cast to java.nio.channels.SocketChannel
我的演员阵容有什么问题?
public class SamplePoolableObjectFactory implements PoolableObjectFactory{
private final static Log log = LogFactory.getLog(SamplePoolableObjectFactory.class);
/* (non-Javadoc)
* @see org.apache.commons.pool.PoolableObjectFactory#activateObject(java.lang.Object)
*/
public void activateObject(Object obj) throws Exception {
log.debug("Activate object ..." + obj.hashCode());
}
/* (non-Javadoc)
* @see org.apache.commons.pool.PoolableObjectFactory#destroyObject(java.lang.Object)
*/
public void destroyObject(Object obj) throws Exception {
log.debug("Destroy object ..." + obj.hashCode());
obj = null;
}
/* (non-Javadoc)
* @see org.apache.commons.pool.PoolableObjectFactory#makeObject()
*/
public Object makeObject() throws Exception {
Object obj = new Object();
log.debug("Make object ..." + obj.hashCode());
return obj;
}
/* (non-Javadoc)
* @see org.apache.commons.pool.PoolableObjectFactory#passivateObject(java.lang.Object)
*/
public void passivateObject(Object obj) throws Exception {
log.debug("Passivate object ..." + obj.hashCode());
}
/* (non-Javadoc)
* @see org.apache.commons.pool.PoolableObjectFactory#validateObject(java.lang.Object)
*/
public boolean validateObject(Object obj) {
log.debug("Validate object ..." + obj.hashCode());
return false;
}
}
和
public class SampleObjectPool extends GenericObjectPool {
private final static Log log = LogFactory.getLog(SampleObjectPool.class);
/**
* Constructor
* @param factory
*/
public SampleObjectPool(PoolableObjectFactory factory) {
super(factory);
log.debug("New pool created with factory ...");
}
/**
* Constructor
* @param factory
* @param config
*/
public SampleObjectPool(PoolableObjectFactory factory, Config config) {
super(factory, config);
log.debug("New pool created with factory and config ...");
}
/* (non-Javadoc)
* @see org.apache.commons.pool.ObjectPool#addObject()
*/
public void addObject() throws Exception {
log.debug("Add an object ...");
super.addObject();
}
/* (non-Javadoc)
* @see org.apache.commons.pool.ObjectPool#borrowObject()
*/
public Object borrowObject() throws Exception {
log.debug("Borrow an object ...");
return super.borrowObject();
}
/* (non-Javadoc)
* @see org.apache.commons.pool.ObjectPool#invalidateObject(java.lang.Object)
*/
public void invalidateObject(Object obj) throws Exception {
log.debug("Invalidate an object ...");
super.invalidateObject(obj);
}
/* (non-Javadoc)
* @see org.apache.commons.pool.ObjectPool#returnObject(java.lang.Object)
*/
public void returnObject(Object obj) throws Exception {
log.debug("Return an object ...");
super.returnObject(obj);
}
}
您的public Object makeObject()
创建一个Object
。 您正在尝试将其SocketChannel
转换为SocketChannel
。
就像猫不是狗一样,无论您尝试投射多少Objects
, Objects
都不是SocketChannels
。
以下是GenericObjectPool.borrowObject()的摘录。
836 // create new object when needed
837 boolean newlyCreated = false;
838 if(null == pair) {
839 try {
840 Object obj = _factory.makeObject();
841 pair = new ObjectTimestampPair(obj);
842 newlyCreated = true;
843 } finally {
844 if (!newlyCreated) {
845 // object cannot be created
846 _numActive--;
847 notifyAll();
848 }
849 }
850 }
如您所见,在提供的PoolableObjectFactory
实例上调用了makeObject()
,因此您应该相应地实现此方法。
现在,您仅返回Object
的实例,该实例当然不能转换为SocketChannel
。
public Object makeObject() throws Exception {
SocketChannel obj = ... // create channel here
log.debug("Make object ..." + obj.hashCode());
return obj;
}
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