lyyb2001

Struts 框架的一大優(yōu)勢在于它允許開發(fā)人員根據(jù)實(shí)際需要來擴(kuò)展框架，定制客戶化的功能。
Struts1.1 框架提供了動態(tài)插入和加載組件的功能，這種組件被稱為 Struts 插件。 Struts 插件實(shí)際上就是一個 Java 類，它在 Struts 應(yīng)用啟動時 Struts 框架調(diào)用每個插件的 init （）方法進(jìn)行初始化，在插件的初始化階段可以完成一些初始化的操作，如建立數(shù)據(jù)庫連接，和遠(yuǎn)程系統(tǒng)建立連接 , 在當(dāng)前的應(yīng)用范圍內(nèi)加入插件類自身的實(shí)例等。在應(yīng)用關(guān)閉時 Struts 框架會調(diào)用每個插件的 destroy() 方法， destroy() 方法可以用來完成釋放資源的任務(wù)，如關(guān)閉數(shù)據(jù)庫連接，斷開與遠(yuǎn)程的連接等。任何作為插件的 Java 類都應(yīng)該實(shí)現(xiàn) org.apache.struts.action.PlugIn 接口。 PlugIn 接口包括兩個方法
????public interface PlugIn {
??????? /**
??????? * 當(dāng) struts 應(yīng)用啟動時，下面的方法將被調(diào)用執(zhí)行
??????? */
??????? public void init(ActionServlet servlet, ApplicationConfig config)
????????????? throws ServletException;

?????? /**
?????? * 當(dāng) struts 應(yīng)用關(guān)閉時，將調(diào)用下面的方法，以釋放資源。
?????? */
??????? public void destroy();?
????}
現(xiàn)在我們用 PLUGIN 實(shí)現(xiàn)日志的創(chuàng)建
< plug-in className = "net.skycity.search.SearchEnginePlugIn" >

??? <!-- 日記索引文件存放的目錄 -->

??????? < set-property property = "logIndexPath" value = "/WEB-INF/log_index" />

??????? <!-- 中文分詞器 -->

??????? < set-property property = "analyzerClass" value = "org.apache.lucene.analysis.standard.StandardAnalyzer" />

</ plug-in>
SearchProxyPlugIn.java
package net.skycity.search;

?

import java.io.File;

import java.io.IOException;

import javax.servlet.ServletException;

import org.apache.log4j.Logger;

import org.apache.lucene.analysis.Analyzer;

import org.apache.lucene.analysis.standard.StandardAnalyzer;

import org.apache.lucene.index.IndexWriter;

import org.apache.struts.action.ActionServlet;

import org.apache.struts.action.PlugIn;

import org.apache.struts.config.ModuleConfig;

?

public class SearchEnginePlugIn implements PlugIn{

??? private static Analyzer analyzer;//設(shè)置lucene要用的切詞方法。

??? protected static ActionServlet servlet = null;

??? protected static String logIndexPath = "/WEB-INF/log_index";//日志索引文件存放目錄

??? protected String analyzerClass;

??? protected Logger log = Logger.getLogger(SearchEnginePlugIn.class);

??? /**

???? * 初始化

???? */

??? public void init(ActionServlet servlet, ModuleConfig config) throws ServletException{

??????? SearchEnginePlugIn.servlet = servlet;

??????? if(analyzerClass==null)

??????? ?? analyzerClass = StandardAnalyzer.class.getName();

??????? try{

??????? ?? analyzer = (Analyzer)Class.forName(analyzerClass).newInstance();

??????? }catch(Exception e){

??????? ?? servlet.log("Initialize Analyzer Failed.",e);

??????? }

??? }

??? /**

???? * 容器停止時，銷毀

???? */

??? public void destroy() {

??? ?? IndexWriter indexWriter;

?????? try {

?????????? indexWriter = getLogIndexWriter();

?????????? indexWriter.close();

?????? } catch (IOException e) {

?????????? e.printStackTrace();

?????? }

??? }

??? /**

???? * 得到日記索引的Writter

???? * @return

???? * @throws IOException

???? */

??? protected static IndexWriter getLogIndexWriter() throws IOException{

??????? String logPath = getLogIndexPath();

??????? File rp = new File(logPath);

??????? if(!rp.exists())

??????????? rp.mkdirs();

??????? File segments = new File(logPath + File.separator + "segments");

??????? boolean bCreate = !segments.exists();

??????? return new IndexWriter(logPath,analyzer,bCreate);

??? }

??? /**

???? * 得到日記索引所在的絕對路徑

???? * @return

???? */

??? public static String getLogIndexPath() {

??? ?? if(logIndexPath.toUpperCase().startsWith("/WEB-INF"))

??? ?????? return servlet.getServletContext().getRealPath(logIndexPath);

??? ?? return logIndexPath;

??? }

??? public void setLogIndexPath(String indexPath) {

??????? logIndexPath = indexPath;

??? }

??? public static Analyzer getAnalyzer() {

??????? return analyzer;

??? }

??? public String getAnalyzerClass() {

?????? return analyzerClass;

??? }

??? public void setAnalyzerClass(String analyzerClass) {

?????? this.analyzerClass = analyzerClass;

??? }

}

Lyyb2001