Lucene系列：LuceneUtils之同步分页
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1、工具类LuceneUtils
LuceneUtils.java
package com.rk.lucene.utils;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.beanutils.BeanUtils;
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.document.Field.Index;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexWriter.MaxFieldLength;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;
import org.junit.Test;
import com.rk.lucene.entity.Article;
import com.rk.lucene.entity.Page;
public class LuceneUtils {
private static Directory directory;
private static Version version;
private static Analyzer analyzer;
private static MaxFieldLength maxFieldLength;
private static final String LUCENE_DIRECTORY= "D:/rk/indexDB";
static{
try {
directory = FSDirectory.open(new File(LUCENE_DIRECTORY));
version = Version.LUCENE_30;
analyzer = new StandardAnalyzer(version);
maxFieldLength = MaxFieldLength.LIMITED;
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
//不让外部new当前帮助类的对象
private LuceneUtils(){}
public static <T> void pagination(Page<T> page,String field,String keyword,Class<T> clazz) throws Exception{
QueryParser queryParser = new QueryParser(getVersion(), field, getAnalyzer());
Query query = queryParser.parse(keyword);
IndexSearcher indexSearcher = new IndexSearcher(getDirectory());
TopDocs topDocs = indexSearcher.search(query, 200);
int totalHits = topDocs.totalHits;
int curPage = page.getCurPage();
int pageSize = page.getPageSize();
int quotient = totalHits / pageSize;
int remainder = totalHits % pageSize;
int totalPages = remainder==0 ? quotient : quotient+1;
int startIndex = (curPage-1) * pageSize;
int stopIndex = Math.min(startIndex + pageSize, totalHits);
List<T> list = page.getItems();
if(list == null){
list = new ArrayList<T>();
page.setItems(list);
}
list.clear();
for(int i=startIndex;i<stopIndex;i++){
ScoreDoc scoreDoc = topDocs.scoreDocs[i];
int docIndex = scoreDoc.doc;
Document document = indexSearcher.doc(docIndex);
T t = document2javabean(document, clazz);
list.add(t);
}
page.setTotalPages(totalPages);
page.setTotalItems(totalHits);
indexSearcher.close();
}
public static <T> void add(T t) throws Exception{
Document document = javabean2document(t);
IndexWriter indexWriter = new IndexWriter(getDirectory(), getAnalyzer(), getMaxFieldLength());
indexWriter.addDocument(document);
indexWriter.close();
}
public static <T> void addAll(List<T> list) throws Exception{
IndexWriter indexWriter = new IndexWriter(getDirectory(), getAnalyzer(), getMaxFieldLength());
for(T t : list){
Document doc = javabean2document(t);
indexWriter.addDocument(doc);
}
indexWriter.close();
}
public static <T> void update(String field,String value,T t) throws Exception{
Document document = javabean2document(t);
IndexWriter indexWriter = new IndexWriter(getDirectory(), getAnalyzer(), getMaxFieldLength());
indexWriter.updateDocument(new Term(field,value), document);
indexWriter.close();
}
public static <T> void delete(String field,String value) throws Exception{
IndexWriter indexWriter = new IndexWriter(getDirectory(), getAnalyzer(), getMaxFieldLength());
indexWriter.deleteDocuments(new Term(field,value));
indexWriter.close();
}
/**
* 删除所有记录
*/
public static void deleteAll() throws Exception {
IndexWriter indexWriter = new IndexWriter(getDirectory(), getAnalyzer(), getMaxFieldLength());
indexWriter.deleteAll();
indexWriter.close();
}
/**
* 根据关键字进行搜索
*/
public static <T> List<T> search(String field,String keyword,int topN) throws Exception{
List<T> list = new ArrayList<T>();
QueryParser queryParser = new QueryParser(getVersion(), field, getAnalyzer());
Query query = queryParser.parse(keyword);
IndexSearcher indexSearcher = new IndexSearcher(getDirectory());
TopDocs topDocs = indexSearcher.search(query, topN);
for(int i=0;i<topDocs.scoreDocs.length;i++){
ScoreDoc scoreDoc = topDocs.scoreDocs[i];
int docIndex = scoreDoc.doc;
System.out.println("文档索引号" + docIndex + "，文档得分：" + scoreDoc.score);
Document document = indexSearcher.doc(docIndex);
T entity = (T) document2javabean(document, Article.class);
list.add(entity);
}
indexSearcher.close();
return list;
}
/**
* 打印List
*/
public static <T> void printList(List<T> list){
if(list != null && list.size()>0){
for(T t : list){
System.out.println(t);
}
}
}
//将JavaBean转成Document对象
public static Document javabean2document(Object obj) throws Exception{
//创建Document对象
Document document = new Document();
//获取obj引用的对象字节码
Class clazz = obj.getClass();
//通过对象字节码获取私有的属性
java.lang.reflect.Field[] reflectFields = clazz.getDeclaredFields();
//迭代
for(java.lang.reflect.Field reflectField : reflectFields){
//反射
reflectField.setAccessible(true);
//获取字段名
String name = reflectField.getName();
//获取字段值
String value = reflectField.get(obj).toString();
//加入到Document对象中去，这时javabean的属性与document对象的属性相同
document.add(new Field(name, value, Store.YES, Index.ANALYZED));
}
//返回document对象
return document;
}
//将Document对象转换成JavaBean对象
public static <T> T document2javabean(Document document,Class<T> clazz) throws Exception{
T obj = clazz.newInstance();
java.lang.reflect.Field[] reflectFields = clazz.getDeclaredFields();
for(java.lang.reflect.Field reflectField : reflectFields){
reflectField.setAccessible(true);
String name = reflectField.getName();
String value = document.get(name);
BeanUtils.setProperty(obj, name, value);
}
return obj;
}
public static Directory getDirectory() {
return directory;
}
public static void setDirectory(Directory directory) {
LuceneUtils.directory = directory;
}
public static Version getVersion() {
return version;
}
public static void setVersion(Version version) {
LuceneUtils.version = version;
}
public static Analyzer getAnalyzer() {
return analyzer;
}
public static void setAnalyzer(Analyzer analyzer) {
LuceneUtils.analyzer = analyzer;
}
public static MaxFieldLength getMaxFieldLength() {
return maxFieldLength;
}
public static void setMaxFieldLength(MaxFieldLength maxFieldLength) {
LuceneUtils.maxFieldLength = maxFieldLength;
}
//测试
public static void main(String[] args) throws Exception {
Article article = new Article(1, "你好", "欢迎来到我的世界");
Document document = javabean2document(article);
Article a2 = (Article) document2javabean(document, Article.class);
System.out.println(a2);
}
}2、entity->dao->service->action
Article.java
package com.rk.lucene.entity;
public class Article {
private Integer id;
private String title;//标题
private String content;//内容
public Article() {
}
public Article(Integer id, String title, String content) {
this.id = id;
this.title = title;
this.content = content;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
@Override
public String toString() {
return "Article [编号=" + id + ", 标题=" + title + ", 内容=" + content + "]";
}
}ArticleDao.java
package com.rk.lucene.dao;
import com.rk.lucene.entity.Article;
import com.rk.lucene.entity.Page;
import com.rk.lucene.utils.LuceneUtils;
public class ArticleDao {
public void pagination(Page<Article> page,String keyword) throws Exception{
LuceneUtils.pagination(page, "content", keyword, Article.class);
}
}ArticleService.java
package com.rk.lucene.service;
import com.rk.lucene.dao.ArticleDao;
import com.rk.lucene.entity.Article;
import com.rk.lucene.entity.Page;
public class ArticleService {
private ArticleDao dao = new ArticleDao();
public Page<Article> pagination(String keyword,int curPage,int pageSize) throws Exception {
Page<Article> page = new Page<Article>();
page.setCurPage(curPage);
page.setPageSize(pageSize);
dao.pagination(page, keyword);
return page;
}
}ArticleServlet.java
package com.rk.lucene.action;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.rk.lucene.entity.Article;
import com.rk.lucene.entity.Page;
import com.rk.lucene.service.ArticleService;
public class ArticleServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
request.setCharacterEncoding("UTF-8");
//获取关键字（此处并不完善，没有对关键字的有效性进行校验）
String keyword = request.getParameter("keyword");
String strPageNo = request.getParameter("pageNo");
//只有当页码真实存在时，才进行查询
if(strPageNo != null && !"".equals(strPageNo)){
int curPage = Integer.parseInt(strPageNo);
//调用业务层
ArticleService service = new ArticleService();
Page<Article> page = service.pagination(keyword, curPage, 2);
//将Page对象绑定到request域对象中
request.setAttribute("PAGE", page);
}
//将keywords变量绑定到request域对象中
request.setAttribute("KEYWORD", keyword);
//转发到list.jsp页面
request.getRequestDispatcher("/index.jsp").forward(request, response);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}在web.xml中注册ArticleServlet
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>lucene01</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>ArticleServlet</servlet-name> <servlet-class>com.rk.lucene.action.ArticleServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ArticleServlet</servlet-name> <url-pattern>/article</url-pattern> </servlet-mapping> </web-app>
3、前台index.jsp页面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>同步分页</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> </head> <body> <!-- 输入区 --> <form action="${pageContext.request.contextPath}/article" method="post"> <input type="hidden" name="pageNo"/> <table border="1" align="center" style="border-collapse:collapse;"> <tr> <th>输入关键字</th> <td><input type="text" name="keyword" value="${requestScope.KEYWORD}" maxlength="10"/> </td> <td><input id="search" type="button" value="站内搜索"/> </td> </tr> </table> <script type="text/javascript"> //去空格 function trim(str){ //先去左边的空格 str = str.replace(/^s*/, ""); //后去右边的空格 str = str.replace(/\s*$/, ""); //返回 return str; } //定位“站内搜索”按钮，同时提供单击事件 document.getElementById("search").onclick = function(){ //定位表单 var formElement = document.forms[0]; //获取关键字 var keyword = formElement.keyword.value; //去空格 keyword = trim(keyword); //判断长度 if(keyword.length == 0){ //提示 alert("你没有填写关键字"); } else{ //提交表单 formElement.pageNo.value = 1; formElement.submit(); } }; </script> </form> <c:if test="${not empty requestScope.PAGE }"> <!-- 显示区 --> <table border="2" align="center" width="70%" style="border-collapse:collapse;"> <tr> <th>编号</th> <th>标题</th> <th>内容</th> </tr> <c:forEach var="article" items="${requestScope.PAGE.items}"> <tr> <td>${article.id}</td> <td>${article.title}</td> <td>${article.content }</td> </tr> </c:forEach> <tr> <th colspan="3" align="center"> <c:choose> <c:when test="${requestScope.PAGE.curPage <= 1 }"> 首页 </c:when> <c:otherwise> <a onclick="fy(1)" style="cursor:hand;color:blue;text-decoration:underline;">首页</a> </c:otherwise> </c:choose> <c:choose> <c:when test="${requestScope.PAGE.curPage <= 1 }"> 上一页 </c:when> <c:otherwise> <a onclick="fy(${requestScope.PAGE.curPage-1})" style="cursor:hand;color:blue;text-decoration:underline;">上一页</a> </c:otherwise> </c:choose> <c:choose> <c:when test="${requestScope.PAGE.curPage >= requestScope.PAGE.totalPages }"> 下一页 </c:when> <c:otherwise> <a onclick="fy(${requestScope.PAGE.curPage+1})" style="cursor:hand;color:blue;text-decoration:underline;">下一页</a> </c:otherwise> </c:choose> <c:choose> <c:when test="${requestScope.PAGE.curPage >= requestScope.PAGE.totalPages }"> 末页 </c:when> <c:otherwise> <a onclick="fy(${requestScope.PAGE.totalPages})" style="cursor:hand;color:blue;text-decoration:underline;">末页</a> </c:otherwise> </c:choose> 共${requestScope.PAGE.totalPages}页，当前第${requestScope.PAGE.curPage}页 </th> </tr> </table> <script type="text/javascript"> function fy(curPage){ //定位表单 var formElement = document.forms[0]; //修改当前页号 formElement.pageNo.value = curPage; //提交表单 formElement.submit(); } </script> </c:if> </body> </html>
| 遇到的一个问题 |
Exception in thread "main" org.apache.lucene.queryParser.ParseException: Encountered "<EOF>" at line 1, column 0. 可能是代码写错了。 错误的代码： Query query = queryParser.Query(keyword); 正确的代码： Query query = queryParser.parse(keyword); |
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