我正在使用下面的 Java 6 代码来查询 Gemfire 6.5 缓存。
我的问题是我正在尝试使用来自该区域中的对象的方法调用来过滤我的结果，但由于某种原因，它抱怨 java.lang.String 不包含我在应该谈论时尝试使用的方法MyEntity，因为正是这个类是缓存中的对象。
我最好的猜测是反序列化有一些有趣的地方，并且该类以 String 类的形式出现，此时它不包含该方法，然后使用该方法转换为 MyEntity 类，并且代码正在尝试调用转换类之前来自 MyEntity 的方法。
package gemfire.run;
import com.gemstone.gemfire.DataSerializable;
import com.gemstone.gemfire.Instantiator;
import com.gemstone.gemfire.cache.client.ClientCache;
import com.gemstone.gemfire.cache.client.ClientCacheFactory;
import com.gemstone.gemfire.cache.query.Query;
import com.gemstone.gemfire.cache.query.QueryService;
import com.gemstone.gemfire.cache.query.SelectResults;
import entity.MyEntity;
public class QueryServerCache {
@SuppressWarnings({ "unchecked", "unused" })
public static void main(String[] args) {
System.out.println("Start Program");
Instantiator.register(new Instantiator(MyEntity.class, 60151) {
@Override
public DataSerializable newInstance() {
return new MyEntity();
}
});
ClientCache clientCache = new ClientCacheFactory().addPoolServer("myServer.net", 12345).set("log-level", "error").create();
QueryService queryService = clientCache.getQueryService();
Query q1 = queryService.newQuery("SELECT DISTINCT * FROM /rootregion/traderegion o WHERE o.getEventId = 'X123'");
Query q = queryService.newQuery("SELECT * FROM /rootregion/traderegion LIMIT 10");
try {
SelectResults<MyEntity> results = (SelectResults<MyEntity>) q1.execute();
System.out.println("\n" + results.size() + "\n");
for (MyEntity o : results) {
System.out.println(o.getEventId());
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("\nExit Program");
}
}
代码的堆栈跟踪是：
Start Program
com.gemstone.gemfire.cache.client.ServerOperationException: While performing a remote query
at com.gemstone.gemfire.cache.client.internal.AbstractOp.processChunkedResponse(AbstractOp.java:323)
at com.gemstone.gemfire.cache.client.internal.QueryOp$QueryOpImpl.processResponse(QueryOp.java:145)
at com.gemstone.gemfire.cache.client.internal.AbstractOp.attemptReadResponse(AbstractOp.java:150)
at com.gemstone.gemfire.cache.client.internal.AbstractOp.attempt(AbstractOp.java:363)
at com.gemstone.gemfire.cache.client.internal.ConnectionImpl.execute(ConnectionImpl.java:245)
at com.gemstone.gemfire.cache.client.internal.pooling.PooledConnection.execute(PooledConnection.java:321)
at com.gemstone.gemfire.cache.client.internal.OpExecutorImpl.executeWithPossibleReAuthentication(OpExecutorImpl.java:646)
at com.gemstone.gemfire.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:108)
at com.gemstone.gemfire.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:84)
at com.gemstone.gemfire.cache.client.internal.PoolImpl.execute(PoolImpl.java:610)
at com.gemstone.gemfire.cache.client.internal.QueryOp.execute(QueryOp.java:47)
at com.gemstone.gemfire.cache.client.internal.ServerProxy.query(ServerProxy.java:80)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.executeOnServer(DefaultQuery.java:248)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:135)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:117)
at gemfire.run.QueryServerCache.main(QueryServerCache.java:33)
Caused by: com.gemstone.gemfire.cache.query.NameNotFoundException: No public attribute named ' getEventId ' was found in class java.lang.String
at com.gemstone.gemfire.cache.query.internal.AttributeDescriptor.getReadMember(AttributeDescriptor.java:184)
at com.gemstone.gemfire.cache.query.internal.AttributeDescriptor.read(AttributeDescriptor.java:70)
at com.gemstone.gemfire.cache.query.internal.AttributeDescriptor.read(AttributeDescriptor.java:56)
at com.gemstone.gemfire.cache.query.internal.PathUtils.evaluateAttribute(PathUtils.java:63)
at com.gemstone.gemfire.cache.query.internal.CompiledPath.evaluate(CompiledPath.java:127)
at com.gemstone.gemfire.cache.query.internal.CompiledComparison.evaluate(CompiledComparison.java:72)
at com.gemstone.gemfire.cache.query.internal.CompiledSelect.doNestedIterations(CompiledSelect.java:449)
at com.gemstone.gemfire.cache.query.internal.CompiledSelect.doNestedIterations(CompiledSelect.java:490)
at com.gemstone.gemfire.cache.query.internal.CompiledSelect.doIterationEvaluate(CompiledSelect.java:376)
at com.gemstone.gemfire.cache.query.internal.CompiledSelect.evaluate(CompiledSelect.java:304)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.executeUsingContext(DefaultQuery.java:382)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:181)
at com.gemstone.gemfire.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:117)
at com.gemstone.gemfire.internal.cache.tier.sockets.BaseCommand.processQueryUsingParams(BaseCommand.java:1216)
at com.gemstone.gemfire.internal.cache.tier.sockets.BaseCommand.processQuery(BaseCommand.java:1167)
at com.gemstone.gemfire.internal.cache.tier.sockets.command.Query.cmdExecute(Query.java:76)
at com.gemstone.gemfire.internal.cache.tier.sockets.BaseCommand.execute(BaseCommand.java:133)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doNormalMsg(ServerConnection.java:758)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doOneMessage(ServerConnection.java:879)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.run(ServerConnection.java:1067)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at com.gemstone.gemfire.internal.cache.tier.sockets.AcceptorImpl$1$1.run(AcceptorImpl.java:504)
at java.lang.Thread.run(Thread.java:662)
Exit Program
使用 Query q 而不是 q1 运行它可以正常工作，因此它似乎确实能够访问 MyEntity 进行反序列化，但是如果我尝试类似的操作：
Query q1 = queryService.newQuery("SELECT DISTINCT * FROM /rootregion/traderegion o WHERE (MyEntity)o.getEventId = 'X123'");
我收到一个错误，不知道 MyEntity 是什么。