private void initDuplicateRemover() {
        BloomFilterDuplicateRemover bloomFilterDuplicateRemover = new BloomFilterDuplicateRemover(this.filePath.hashCode());
        setDuplicateRemover(bloomFilterDuplicateRemover);
    }
Store urls and cursor in files so that a Spider can resume the status when shutdown.<br>

@author code4crafter@gmail.com <br>
@since 0.2.0
webmagic-extension/src/main/java/us/codecraft/webmagic/scheduler/FileCacheQueueScheduler.java