求：怎么加快lucene写文件的效率（附代码）

求：如何加快lucene写文件的效率（附代码）
package com.ffcs.nss.server.lucene;

import java.io.File;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

import com.ffcs.nss.net.IP;
import com.ffcs.nss.util.Validators;

public class LuceneIndexer {

protected final Log logger = LogFactory.getLog(getClass());
private Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT); // 创建一个语法分析器
public static final int mergeFactor = 10000;
public static final int RAM_BUFFER_SIZE = 256;
private String dir;
private String json;
public static int num;
private List<EventCommon> events = new ArrayList<EventCommon>();

public LuceneIndexer(String dir, List<EventCommon> events) {
this.dir = dir;
this.events = events;
}

public void make() {

IndexWriter fsWriter = null;
Directory directory = null;

try {
String subdir = "lucene";

directory = FSDirectory.open(new File(dir + System.getProperty("file.separator") + subdir));


// create ram & fs writer
fsWriter = new IndexWriter(directory, analyzer, create, IndexWriter.MaxFieldLength.LIMITED);

fsWriter.setMergeFactor(mergeFactor);
fsWriter.setRAMBufferSizeMB(RAM_BUFFER_SIZE);

for (EventCommon ec : events) {

Document doc = new Document();

String businessid = ec.getBusinessid();
String placeid = ec.getPlaceid();
String placename = ec.getPlacename();
String domainid = ec.getDomainid();
String domainname = ec.getDomainname();


doc.add(new Field("businessid",
Validators.isNotnull(businessid) ? businessid : "",
Field.Store.YES, Field.Index.NOT_ANALYZED));
doc.add(new Field("placeid",
Validators.isNotnull(placeid) ? placeid : "",
Field.Store.YES, Field.Index.NOT_ANALYZED));
doc.add(new Field("placename",
Validators.isNotnull(placename) ? placename : "",
Field.Store.YES, Field.Index.NOT_ANALYZED));
doc.add(new Field("domainid",
Validators.isNotnull(domainid) ? domainid : "",
Field.Store.YES, Field.Index.NOT_ANALYZED));
doc.add(new Field("domainname",
Validators.isNotnull(domainname) ? domainname : "",
Field.Store.YES, Field.Index.NOT_ANALYZED));

// save document to index writer
fsWriter.addDocument(doc);
}
long end = System.currentTimeMillis();