迭代器模式用于处理具有（ ）性质的类。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='30258' and id < 2447820 and id<>'2447820' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='30258' and id > 2447820 and id<>'2447820' order by id asc limit 5