Create a full-text search reference value for your system: 2)

I mentioned Lucene again in this article. In the Java industry, when it comes to full-text retrieval, almost no one knows about it.
Search by Google. The world is full of related information. The Representative is che Dong's "Java-based full-text indexing engine Lucene Introduction ",
I want to write only the simplest three axes, plus chineseanalyzer that supports Chinese and the method for sorting search results by time.
These materials can be found elsewhere. I just put them forward as a solution to the troubles frequently encountered in the CE application.
Last year, a friend on MSN told me that he wanted to use Lucene to build a full-text search for a website. At that time, I thought it was very simple. It was okay to say it was okay,
However, he mentioned that the search results should be sorted by time. I checked some information and found that Lucene does not provide a custom sorting method,
However, they can only be sorted by their own relevance algorithms. Later, I found indexordersearcher IN THE weblucene project of chelong.
Solved the regular requirements of result sorting.
Indexordersearcher is similar to General indexsearch. You only need to add the indexordersearcher. order_by_docid_desc parameter when constructing an object.
Indexordersearcher indexsearcher = new indexordersearcher ("/home/deleetest/Index", indexordersearcher. order_by_docid_desc );
The new version of Lucene also provides a multifieldqueryparser that can retrieve multiple fields at the same time. Previously, queryparser was troublesome.
Private Static chineseanalyzer = new chineseanalyzer ();
Public hits search (string querytext ){
If (querytext = NULL ){
Return NULL;
}
Query query;
Try {
Query = multifieldqueryparser. parse (querytext, new string [] {"title"}, chineseanalyzer );
Return indexsearcher. Search (query );
} Catch (exception e ){
Return NULL;
}
}
The following describes how to create an index and regularly retrieve the data index from the database. After the record is completed, I write the time into a TXT file.
Package com. Test. search;

Import org. Apache. Lucene. analysis. analyzer;
Import org.apache.e.analysis.cn .*;
Import org. Apache. Lucene. analysis. Standard. standardanalyzer;
Import org.apache.e.doc ument .*;
Import org. Apache. Lucene. Index .*;

Import java. Io .*;
Import java. SQL .*;
Import java. util. date;

Import com. Test. DB .*;
Import com. Test. Utility .*;

/**
* Title: searchindexer
* Description: Full-text index
* Copyright: Copyright (c) 2001
* Company: Test
* @ Author Sean
* @ Version 1.0
*/
Public class searchindexer {
Private string indexpath = NULL;
Protected analyzer = new chineseanalyzer ();

Public searchindexer (string s ){
This. indexpath = s;
}
/**
* Index all documents before a certain date
* @ Param fromdate
* @ Return
*/
Public final void updateindex (string fromdate ){
Connection conn = dbutil. getcon ();
Indexwriter = NULL;
Try {
Indexwriter = getwriter (false );
// Index internal system file Publishing
Preparedstatement PSTM = conn. preparestatement (
"Select title, body, creationtime from document where creationtime>'' "+ fromdate +
"''Order by creationtime ");
Resultset rs = p0000.exe cutequery ();
While (Rs. Next ()){
String creationtime = Rs. getstring ("creationtime ");
String title = Rs. getstring ("title ");
String body = Rs. getstring ("body ");

If (Title = NULL | body = NULL ){
Continue;
}
Try {
Adddocstoindex (title, body, creationtime, indexwriter );
}
Catch (exception ex ){
Ex. printstacktrace ();
}
}
Indexwriter. Optimize ();
}
Catch (exception ex ){
Ex. printstacktrace ();
}
Finally {
Try {
Indexwriter. Close ();
Conn. Close ();
}
Catch (exception e ){
E. printstacktrace ();
}
}
}
/**
* Check whether the index file exists.
* @ Param s
* @ Return indicates whether the index exists.
*/
Private Boolean indexexists (string s ){
File file = new file (s + file. Separator + "segments ");
Return file. exists ();
}
/**
* Add an index group.
* @ Param title
* @ Param body
* @ Param creationtime
* @ Param indexwriter
* @ Return
*/
Private final void addnewstoindex (string docid, string URL, String title, string body,
String ptime, indexwriter) throws
Ioexception {
If (indexwriter = NULL ){
Return;
}
Else {
Try {
Document document = new document ();
Document. Add (field. Text ("title", title ));
Document. Add (field. Text ("body", body ));
Document. Add (new field ("creationtime", creationtime, true, true, false ));
Indexwriter. adddocument (document );
}
Catch (exception ex ){
Ex. printstacktrace ();
}
Return;
}
}
/**
* Get indexwriter
* @ Param flag whether to create an index
* @ Return indexwriter
*/
Private indexwriter getwriter (Boolean flag) throws ioexception {
String S = indexpath;
If (S = NULL ){
Throw new ioexception ("index file path setting error .");
}
Indexpath = S + file. Separator + "Search ";
Indexwriter = NULL;
If (FLAG ){
Try {
Indexwriter = new indexwriter (indexpath, analyzer, true );
}
Catch (exception ){
System. Err. println ("error: failed to create a new index writer .");
Exception. printstacktrace ();
}
}
Else {
If (indexexists (indexpath )){
Try {
Indexwriter = new indexwriter (indexpath, analyzer, false );
}
Catch (exception exception1 ){
System. Err. println ("error: failed to open an index writer .");
Exception1.printstacktrace ();
}
}
Else {
Try {
Indexwriter = new indexwriter (indexpath, analyzer, true );
}
Catch (exception exception2 ){
System. Err. println ("error: failed to create a new index writer .");
Prediction2.printstacktrace ();
}
}
}
Return indexwriter;
}

Public static void main (string [] ARGs ){
String lastupdate = "/home/lucenetest/lastupdate.txt ";
Searchindexer = new searchindexer ("/home/lucenetest/Index ");
// Retrieve the last update time
String STR = util. readtxtfile (lastupdate );
If (STR = NULL | Str. Length () = 0 ){
STR = new java. util. Date (). tostring ();
}
Searchindexer. updateindex (STR );
// Current write time
Util. writetxtfile (lastupdate, new java. util. Date (), false );
}
}
Write a cmd or sh command to regularly execute searchindexer in the corresponding operating system.