compass搜索引擎的应用
前阵子在做一个手机服务器端系统的开发，主要使用spring+hibernate框架，由于系统涉及到全文检索功能，所以很自然地就想到了compass这个开源的搜索引擎，并且在j2ee领域，个人觉得目前最好用的就是这个了。为了提高系统的性能，我们大量的使用了compass创建的索引来做数据查询，因为我们主要功能是数据查询，很少做数据的更改，所以比较适合用这种方式，也收到了很好的效果。
首先是spring与compass的集成配置文件：applicationContext-compass.xml
<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd" default-lazy-init="true"><!-- 配置compass注解 --><bean id="annotationConfiguration" ref="annotationConfiguration"></property> <property name="compassSettings"> <props> <!-- compass事务工厂 --> <prop key="compass.transaction.factory">org.compass.spring.transaction.SpringSyncTransactionFactory</prop> <!-- paoding分词器 --> <prop key="compass.engine.analyzer.MMAnalyzer.CustomAnalyzer">net.paoding.analysis.analyzer.PaodingAnalyzer</prop> <!-- 设置高亮显示 --> <prop key="compass.engine.highlighter.default.formatter.simple.pre"><![CDATA[<font color="#cc0033"><b>]]></prop> <prop key="compass.engine.highlighter.default.formatter.simple.post"><![CDATA[</b></font>]]></prop> </props> </property> <property name="transactionManager" ref="transactionManager" /></bean><!-- 用Hibernate3事件系统,支持Real Time Data Mirroring.经Hiberante改变的数据会自动被反射到索引里面 --><bean id="hibernateGpsDevice" ref="sessionFactory" /> <property name="mirrorDataChanges"> <value>true</value> </property> </bean> <!-- 同步更新索引 --> <bean id="compassGps" init-method="start" destroy-method="stop"><property name="compass" ref="compass" /><property name="gpsDevices"><list><bean value="hibernateDevice"/><property name="sessionFactory" ref="sessionFactory"/></bean></list></property> </bean> <bean id="compassTemplate" ref="compass" /> </bean></beans>
?接着是实体的compass注解，将需要创建索引的实体及实体属性标注：
@Entity@Table(name="B_ENTITY_BASE")@Searchablepublic class MobileBaseEntity implements Serializable {private static final long serialVersionUID = -5594658438463757978L;@SearchableIdprotected String id;@SearchableProperty(name = "keys")protected String name;@SearchableProperty(index = Index.NO, store = Store.YES)protected String address;protected String phone;protected String description;@SearchableProperty(index = Index.NO, store = Store.YES)protected Double longitude;@SearchableProperty(index = Index.NO, store = Store.YES)protected Double latitude;@SearchableProperty(index = Index.NO, store = Store.YES)protected String type;protected String channel;protected String knowledgeId;protected String stauts;//0审核退回，1审核中，2正常}@SearchableId：不要求定义搜索的元数据；
@SearchableProperty(name = "keys")：属性索引的别名，这个别名在做查询的时候会用到，我们可以把多个实体类的多个属性定义为同一个别名来做全文检索；
@SearchableProperty(index = Index.NO, store = Store.YES)：保存这个属性的值，但不作为索引。index = Index.XXX，这个有几种策略，1：NOT_ANALYZED ，不分词但创建索引；2：ANALYZED，分词并创建索引。
@SearchableComponent：关联复合索引，用以复合类型；
@SearchableReference：用以引用类型。
接下来就是使用compass的API来做数据查询，首先是模糊匹配查询，
List<BusLine> busLineList = new ArrayList<BusLine>();Compass compass = this.compassTemplate.getCompass();CompassSession compassSession = compass.openSession();CompassQueryBuilder queryBuilder = compassSession.queryBuilder(); //指定查询实体CompassQuery queryAlias = queryBuilder.alias(BusLine.class.getSimpleName());CompassBooleanQueryBuilder boolQueryBuilder = queryBuilder.bool();boolQueryBuilder.addMust(queryAlias);boolQueryBuilder.addMust(queryBuilder.wildcard("baseEntityKeys", "*"+value+"*"));CompassHits compassHits = boolQueryBuilder.toQuery().hits();if(compassHits != null && compassHits.length() > 0) {for(int i = 0; i < compassHits.length(); i++) {BusLine line = (BusLine)compassHits.data(i);busLineList.add(line);}}compassSession.close();return busLineList;?至于是使用模糊匹配查询还是全文检索，这需要根据应用场景来选择，能使用模糊匹配的话尽量使用，全文检索的代价比模糊匹配要高。全文检索的例子：
String keywords = keyword.trim();List<KnowledgeInfo> result = new ArrayList<KnowledgeInfo>();Properties prop = PropertyUtil.readPropertyFile();String type = prop.getProperty("knowledge.zc.type");ChannelInfo channel = channelInfoService.getChannelById(type);Compass compass = this.compassTemplate.getCompass();CompassSession session = compass.openSession();CompassQueryBuilder builder = session.queryBuilder();CompassBooleanQueryBuilder boolBuidler = builder.bool();boolBuidler.addMust(builder.wildcard("sort", channel.getSort()+"*"));if(keywords != null && !"".equals(keywords)) { String[] array = keywords.split(" "); if (array != null && array.length > 0) { for (String value : array) { if (value != null && StringUtils.isNotEmpty(value.trim())) {boolBuidler.addMust(builder.queryString("keys:" + value).toQuery()); } } } CompassHits hits = boolBuidler.toQuery().hits(); if (hits != null && hits.length() > 0) { for (int i = 0; i < hits.length(); i++) { KnowledgeInfo info = (KnowledgeInfo) hits.data(i); String ht = hits.highlighter(i).fragment("keys"); if (null != ht) { info.setKeywords(ht); } result.add(info); } }}session.close();return result;?compass一个简单的应用就完成了。