docs: public void train(Reader reader, String modelFile) throws Exception {
  		/**
  		 * 分类模型
  		 */
  		//建立字典管理器
  		AlphabetFactory af = AlphabetFactory.buildFactory();
  
  		//使用n元特征
  		Pipe ngrampp = new NGram(new int[] {1,2});
  		//将字符特征转换成字典索引
  		Pipe indexpp = new StringArray2IndexArray(af);
  		//将目标值对应的索引号作为类别
  		Pipe targetpp = new Target2Label(af.DefaultLabelAlphabet());		
  
  		//建立pipe组合
  		SeriesPipes pp = new SeriesPipes(new Pipe[]{ngrampp,targetpp,indexpp});
  		
  		SeriesPipes  pp2 = new SeriesPipes(new Pipe[]{prePipe, ngrampp,targetpp,indexpp});
  		
  		InstanceSet instset = new InstanceSet(pp2,af);
  
  
  
  		//读入数据，并进行数据处理
  		instset.loadThruStagePipes(reader);
  
  		/**
  		 * 建立分类器
  		 */		
  		OnlineTrainer trainer = new OnlineTrainer(af,100);
  		trainer.c = 0.01f;
  		pclassifier = trainer.train(instset);
  		pp.removeTargetPipe();
  		pclassifier.setPipe(pp);
  		af.setStopIncrement(true);
  
  		//将分类器保存到模型文件
  		pclassifier.saveTo(modelFile);	
  	}