RMI客户端与服务端交互问题

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RMI客户端与服务端交互问题20

最近用rmi做一个聊天的小程序。在客户端和服务端交互过程中。偶尔会出现连接失败的问题：

具体错误信息如下：

服务端：

[framework] 2012-09-03 16:34:13,102 - org.hibernate.util.JDBCExceptionReporter -749084 [RMI TCP Connection(54)-192.168.100.1] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: null

[framework] 2012-09-03 16:34:13,102 - org.hibernate.util.JDBCExceptionReporter -749084 [RMI TCP Connection(54)-192.168.100.1] ERROR org.hibernate.util.JDBCExceptionReporter - An attempt by a client to checkout a Connection has timed out.

[framework] 2012-09-03 16:34:23,108 - org.hibernate.util.JDBCExceptionReporter -759090 [RMI TCP Connection(54)-192.168.100.1] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: null

[framework] 2012-09-03 16:34:23,108 - org.hibernate.util.JDBCExceptionReporter -759090 [RMI TCP Connection(54)-192.168.100.1] ERROR org.hibernate.util.JDBCExceptionReporter - An attempt by a client to checkout a Connection has timed out.

客户端：

java.rmi.UnmarshalException: Error unmarshaling return; nested exception is:
    java.lang.ClassNotFoundException: org.hibernate.exception.GenericJDBCException (no security manager: RMI class loader disabled)
    at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
    at sun.rmi.server.UnicastRef.invoke(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
    at $Proxy1.searchUser(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.remoting.rmi.RmiClientInterceptorUtils.invokeRemoteMethod(RmiClientInterceptorUtils.java:108)
    at org.springframework.remoting.rmi.RmiClientInterceptor.doInvoke(RmiClientInterceptor.java:362)
    at org.springframework.remoting.rmi.RmiClientInterceptor.invoke(RmiClientInterceptor.java:258)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
    at $Proxy0.searchUser(Unknown Source)
    at com.qq.client.ChatWindow.crateChatContent(ChatWindow.java:221)
    at com.qq.client.ChatWindow.refChat(ChatWindow.java:251)
    at com.qq.client.ChatWindow$2.actionPerformed(ChatWindow.java:174)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.hibernate.exception.GenericJDBCException (no security manager: RMI class loader disabled)
    at sun.rmi.server.LoaderHandler.loadClass(Unknown Source)
    at sun.rmi.server.LoaderHandler.loadClass(Unknown Source)
    at java.rmi.server.RMIClassLoader$2.loadClass(Unknown Source)
    at java.rmi.server.RMIClassLoader.loadClass(Unknown Source)
    at sun.rmi.server.MarshalInputStream.resolveClass(Unknown Source)
    at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
    at java.io.ObjectInputStream.readClassDesc(Unknown Source)
    at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)

初步一看以为是c3p0连接池，连接超时了。

然后改了超时等等配置。结果还是会出现这种错误。并且数据库已经查询出来值了。

连接池配置：

# Database URL
jdbc.url=jdbc:oracle:thin:@192.168.100.2:1521:orcl
# Database ClassDriver
jdbc.driver=oracle.jdbc.driver.OracleDriver
# Database login information
jdbc.username=qq
jdbc.password=8hZktr+qiZ8=
# Time to wait for an open connection before timing out
# (in milliseconds)
cpool.checkoutTimeout=10000
# Connection pool size
cpool.minPoolSize=5
cpool.maxPoolSize=40
# How long to keep unused connections around(in seconds)
# Note: MySQL times out idle connections after 8 hours(28,800 seconds)
# so ensure this value is below MySQL idle timeout
cpool.maxIdleTime=25200
# How long to hang on to excess unused connections after traffic spike
# (in seconds)
cpool.maxIdleTimeExcessConnections=0
# Acquiring new connections is slow, so eagerly retrieve extra connections
# when current pool size is reached
cpool.acquireIncrement=5
#60s check pool can get connection num
cpool.idleConnectionTestPeriod=60
#max statment
cpool.maxStatements=10

客户端RMI配置：

<bean id="serviceClient"
            class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
            <property name="serviceInterface">
               <value>com.qq.db.DBUser</value>
           </property>
           
           <property name="serviceUrl" value="rmi://${servers.server}:${servers.port}/${server.serverName}" />
           <property name="lookupStubOnStartup">
             <value>false</value>
        </property>
           <property name="refreshStubOnConnectFailure">
                <value>true</value>
         </property>
       </bean>

服务端RMI spring配置：

<bean id="registry" class="org.springframework.remoting.rmi.RmiRegistryFactoryBean">
       <property name="port" value="${port}"/>
    </bean>
    <bean id = "serviceExporter" class = "org.springframework.remoting.rmi.RmiServiceExporter" >
        <property name="registryHost" value="${servers}" />
        <property name = "serviceName" value = "${serviceName}" />
        <property name = "service" ref = "DBUserImpl" />
        <property name = "serviceInterface" value = "com.qq.db.DBUser" />
        <property name="registry" ref="registry"/>

    </bean>

只要客户端频繁操作或者操作一会儿就会出现这类错误。

小弟刚刚接触RMI 。不是很清清楚怎么回事。

还请大家帮我解决下。谢谢！！！

问题补充：好像就是数据库连接的问题。

数据库操作类
public class DBUserImpl extends HibernateDaoSupport implements DBUser {

我在finally中这样写的

}finally{
try {
closeConnection(conn,null,psmt);
if(super.getSession()!=null){
super.getSession().close();
}
} catch (Exception e) {
e.printStackTrace();
}

关闭了session也关闭了conn等等。

不知道是不是这个问题、

是不需要关闭conn等等吗？只关闭session？？？

问题补充：我贴一个完整的数据库存操作的方法吧！

类还是这样定义的：
public class DBUserImpl extends HibernateDaoSupport implements DBUser
其中的一个方法：
//用户注册
public String insertUser(User u) {
String result = "";
Connection conn = null;
PreparedStatement psmt = null;
//userid是否存在
String uid =QQID.createUserID();
User user = new User();
user.setUserid(uid);
User userid = searchUser(user);
if(userid!=null){
insertUser(u);
}
try {
String sql = "insert into user_qq (uuid,userid,username,userpass)values (SEQ_USER_QQ.NEXTVAL,?,?,?)";
conn=(Connection)super.getHibernateTemplate().getSessionFactory().openSession().connection();
psmt = conn.prepareStatement(sql);
psmt.setString(1, uid);
psmt.setString(2, u.getUsername());
QQID.getKey(KEY); //加密key
psmt.setString(3, QQID.getEncString(u.getUserpass()));
if(psmt.executeUpdate()>0)
{
log_.info("用户【"+uid+"】注册成功！");
result = uid;
}
} catch (SQLException e) {
log_.error("用户【"+uid+"】注册失败！",e);
}finally{
try {
closeConnection(conn,null,psmt);
if(super.getSession()!=null){
super.getSession().close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}

2012年9月04日 17:32

java_落尘
4
0 0 6

3个答案按时间排序按投票排序

0 0

先关闭session.在关闭con

2012年9月04日 18:22

demojava
2207
1 3 134

添加评论

0 0

既然你继承了HibernateDaoSupport，你就不必自己管事务及连接释放了，交给spring来完成吧
public class DBUserImpl extends HibernateDaoSupport implements DBUser

这些代码没必要的话都可以去掉：
}finally{
try {
closeConnection(conn,null,psmt);
if(super.getSession()!=null){
super.getSession().close();
}
} catch (Exception e) {
e.printStackTrace();
}

能否贴段完成的。怀疑你这段代码可能造成连接没有返回。

cpool.checkoutTimeout=10000
# Connection pool size
cpool.minPoolSize=5
cpool.maxPoolSize=40 ----> 这个也有可能是连接没有释放造成的。

既然你继承了HibernateDaoSupport 把Connection的管理就交给spring吧，不要自己再closeConnection(conn,null,psmt);