数组指针异常处理，怎么改？
import import
import
import
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
public class Search {
private String INDEX_STORE_PATH = "f:\\index";
public void indexSearch(String searchType, String searchKey) {
try {
// 根据索引位置建立IndexSearcher
IndexSearcher searcher = new IndexSearcher(INDEX_STORE_PATH);
// 建立搜索单元，searchType代表要搜索的Filed，searchKey代表关键字
Term t = new Term(searchType, searchKey);
// 由Term生成一个Query
Query q = new TermQuery(t);
// 搜索开始时间
Date beginTime = new Date();
// 获取一个<document, frequency>的枚举对象TermDocs
TermDocs termDocs = searcher.getIndexReader().termDocs(t);
while (termDocs.next()) {
// 输出在文档中出现关键词的次数
System.out.println(termDocs.freq());
// 输出搜索到关键词的文档
// System.out.println(searcher.getIndexReader().document(termDocs.doc()));
}
// 搜索完成时间
Date endTime = new Date();
// 搜索所耗时间
long timeOfSearch = endTime.getTime() - beginTime.getTime();
System.out
.println("The time For indexsearch is " + timeOfSearch + " ms");
} catch (IOException e) {
e.printStackTrace();
}
}
public void StringSearch(String keyword, String searchDir) {
File filesDir = new File(searchDir);
// 返回目录文件夹所有文件数组
52行 File[] files= filesDir.listFiles();
// HashMap保存文件名和匹配次数对
Map rs = new HashMap();
// 记录搜索开始时间
Date beginTime = new Date();
// 遍历所有文件
第59行 for (int i = 0; i < files.length; i++) {
// 初始化匹配次数
int hits = 0;
try {
// 读取文件内容
BufferedReader br = new BufferedReader(new FileReader(files[i]));
StringBuffer sb = new StringBuffer();
String line = br.readLine();
while (line != null) {
sb.append(line);
line = br.readLine();
}
br.close();
// 将StringBuffer转化成String，以便于搜索
String stringToSearch = sb.toString();
// 初始化fromIndex
int fromIndex = -keyword.length();
// 逐个匹配关键词
while ((fromIndex = stringToSearch.indexOf(keyword, fromIndex
+ keyword.length())) != -1) {
hits++;
}
// 将文件名和匹配次数加入HashMap
rs.put(files[i].getName(), new Integer(hits));
} catch (IOException e) {
e.printStackTrace();
}
}
// 输出查询结果
Iterator it = rs.keySet().iterator();
while (it.hasNext()) {
String fileName = (String) it.next();
Integer hits = (Integer) rs.get(fileName);
System.out.println("find " + hits.intValue() + " matches in "
+ fileName);
}
// 记录结束时间
Date endTime = new Date();
// 得到搜索耗费时间
long timeOfSearch = endTime.getTime() - beginTime.getTime();
System.out.println("The time For string search is " + timeOfSearch + " ms");
}
}
Exception in thread "main" java.lang.NullPointerException
at ch2.lucenedemo.process.Search.StringSearch(Search.java:59)
我知道是files.length异常，求救怎么改？？？
