Java InvalidRequestException（原因：日期应为8或0字节长）cassandra

我是卡桑德拉的新手。我正在尝试创建一个列族，其中包含一个复合键，该键包含longtype for timestamp。代码如下：

Composite cs = new Composite(); 
cs.addComponent(id, StringSerializer.get());
cs.addComponent(tstamp, DateSerializer.get());
Mutator mutator  = HFactory.createMutator(keyspace, stringSerializer);
mutator.insert(id, cf.getName(), HFactory.createColumn(cs, id, CompositeSerializer.get(), StringSerializer.get()));
                 mutator.insert( id, cf.getName(), HFactory.createColumn("ipaddress", usrlog.getIpaddress()));
                 mutator.insert( id, cf.getName(), HFactory.createColumn("timestamp", tstamp.getTime(), StringSerializer.get(), LongSerializer.get()));
                 mutator.insert( id, cf.getName(), HFactory.createColumn("search_term", usrlog.getSearchterm()));
                 mutator.insert( id, cf.getName(), HFactory.createColumn("user_agent", usrlog.getUseragent()));

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因为您插入了错误的日期。长度不合适