关于Lucene索引合并解决方法

package com.pccw;

import java.io.File;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.FSDirectory;

public class AdvancedTextFileIndexer {
    /**
     * @author Shane Zhao about merge Index in PCCW BJDEV
     * 将小索引文件合并到大的索引文件中去
     *
     * @param from
     *            将要合并到to文件的文件
     * @param to
     *            将from文件合并到该文件
     * @param sa
     */
    private static void mergeIndex(File from, File to,StandardAnalyzer sa) {
        IndexWriter indexWriter = null;
        try {
            System.out.println("正在合并索引文件!\t ");
            indexWriter = new IndexWriter(to, sa, false);
            indexWriter.setMergeFactor(100000);
            indexWriter.setMaxFieldLength(Integer.MAX_VALUE);
            indexWriter.setMaxBufferedDocs(Integer.MAX_VALUE);
            indexWriter.setMaxMergeDocs(Integer.MAX_VALUE);
            FSDirectory[] fs = { FSDirectory.getDirectory(from, false) };
            indexWriter.addIndexes(fs);
            indexWriter.optimize();
            indexWriter.close();
            System.out.println("已完成合并!\t ");
        } catch (Exception e) {
            System.out.println("合并索引出错！");
            e.printStackTrace();
        } finally {
            try {
                if (indexWriter != null)
                    indexWriter.close();
            } catch (Exception e) {

            }

        }

    }

    public static void main(String[] areg){
        File from = new File("F:/web/faq/lucene/indexDir");
        File to = new File("F:/indexDir");
        mergeIndex(from,to,new StandardAnalyzer());
    }

}