【解决办法】通过权值字段集合类（WeightFieldInfos）设置，该类是权值字段信息对象（WeightFieldInfo）的集合，用于对权值字段信息对象进行管理。
详细代码如下：
WeightFieldInfos weightFieldInfos = new WeightFieldInfos();
WeightFieldInfo weightFieldInfolength = new WeightFieldInfo();
weightFieldInfolength.setFTWeightField("smLength");
weightFieldInfolength.setTFWeightField("smLength");
weightFieldInfolength.setName("length");
weightFieldInfos.add(weightFieldInfolength);
