Compass是第一个实现java搜索引擎的开源框架,它是基于Lucene之上的,提供更简单的搜索引擎API,事务支持,对象到搜索引擎映射(Annotations & XML),Xml到搜索引擎映射,可以和Hibernate,Spring集成,功能非常的强大。如果用Hibernate,Spring做的项目需要搜索引擎的话,Compass是个非常好的选择。个人认为:如果说Lucene是搜索引擎中的JDBC,那么Compass就是Hibernate。而Compass和Hibernate不仅仅是比喻的像,它们的类和用法,和作用也非常的像。Compass是用面向对象编程方法来实现搜索。如果会Hibernate的话学Compass是非常容易的。
大家可以到http://www.opensymphony.com/compass/download.action去下载最新的版本。2006年8月28日Compass 1.1 M1 发布,用的是Lucene2.0,现在讲的就是这个版本。
虽然有人说Hibernate3.1以后版本自带了对Lucene的支持,Compass好像没用,但是只要看一下Hibernate源代码可以看出Hibernate对Lucene的支持很简陋,且不支持事务并且Hibernate3.2用的还是Lucene版本是Lucene1.4.3,所以说当做大的项目的时候Compass还是非常有必要的。
还是先看个HelloWorld程序:(这里的测试功能的例子都是用的JUnit测试用例,为方便阅读异常全部抛出)
一共4个文件Article.java, compass.cfg.xml,Article.cpm.xml,JUnit插入测试。
1.Article.java:
- package org.li.compass;
- import java.util.Date;
- public class Article
- {
- private long id;
- private String title;
- private String content;
- private Date publishDate;
- public String getContent()
- {
- return content;
- }
- public void setContent(String content)
- {
- this.content = content;
- }
- public Date getPublishDate()
- {
- return publishDate;
- }
- public void setPublishDate(Date publishDate)
- {
- this.publishDate = publishDate;
- }
- public String getTitle()
- {
- return title;
- }
- public void setTitle(String title)
- {
- this.title = title;
- }
- public long getId()
- {
- return id;
- }
- public void setId(long id)
- {
- this.id = id;
- }
- }
package org.li.compass;
import java.util.Date;
public class Article
{
private long id;
private String title;
private String content;
private Date publishDate;
public String getContent()
{
return content;
}
public void setContent(String content)
{
this.content = content;
}
public Date getPublishDate()
{
return publishDate;
}
public void setPublishDate(Date publishDate)
{
this.publishDate = publishDate;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
public long getId()
{
return id;
}
public void setId(long id)
{
this.id = id;
}
}
上面就是一个Article的POJO类上面有文章题目,内容,发布时间,这里的id的compass必须的(有点和数据库一样了)。
2.compass.cfg.xml
- <!DOCTYPE compass-core-configuration PUBLIC
- "-//Compass/Compass Core Configuration DTD 1.0//EN"
- "http://www.opensymphony.com/compass/dtd/compass-core-configuration.dtd">
- <compass-core-configuration>
- <compass>
- <setting name="compass.engine.connection">target/test</setting><!-- 这里配置的是索引的相对路径 -->
- <mapping resource="org/li/compass/Article.cpm.xml"/><!-- 这里是每个对象的映射文件 -->
- </compass>
- </compass-core-configuration>
这是Compass的配置文件上面标明了索引目录和映射文件。映射好文件了就看看这个映射的什么吧
3. Article.cpm.xml
- <!DOCTYPE compass-core-mapping PUBLIC
- "-//Compass/Compass Core Mapping DTD 1.0//EN"
- "http://www.opensymphony.com/compass/dtd/compass-core-mapping.dtd">
- <compass-core-mapping package="org.li.compass">
- <class name="Article" alias="article">
- <!-- 这是必须有的 -->
- <id name="id"/>
- <!-- 你可以通过这个配置来在底层给这个对象加一个Field("type","java") -->
- <constant>
- <meta-data>type</meta-data>
- <meta-data-value>java</meta-data-value>
- </constant>
- <!-- 配置一下属性 -->
- <property name="title">
- <meta-data>titleIndex</meta-data>
- </property>
- <property name="content">
- <meta-data>contentIndex</meta-data>
- </property>
- <property name="publishDate">
- <meta-data>publishDateIndex</meta-data>
- </property>
- </class>
- </compass-core-mapping>
这个配置应该可以看的懂吧可能会有人问meta-data是干什么用的??
它的值是作为底层Field的名字,如果没有配置的话Compass用$article/…来代替。而它的作用是配置对象的属性的储存形式,Compass就是读取它来new Field()的:
- <!ELEMENT meta-data (
- #PCDATA
- )>
- <!ATTLIST meta-data store (no|yes|compress) "yes">
- <!ATTLIST meta-data index (no|tokenized|un_tokenized) "tokenized">
- <!ATTLIST meta-data term-vector (no|yes|positions|offsets|positions_offsets) "no">
- <!ATTLIST meta-data reverse (no|reader|string) "no">
- <!ATTLIST meta-data analyzer CDATA #IMPLIED>
- <!ATTLIST meta-data exclude-from-all (true|false) #IMPLIED>
- <!ATTLIST meta-data converter CDATA #IMPLIED>
- <!ATTLIST meta-data format CDATA #IMPLIED>
- <!ATTLIST meta-data boost CDATA #IMPLIED>
4.JUnit插入测试
- public void InsertCompass()
- {
- CompassConfiguration comConfig = new CompassConfiguration().configure().addClass(Article.class);
- Compass com = comConfig.buildCompass();
- CompassSession comSession = com.openSession();
- CompassTransaction comTx = comSession.beginTransaction();
- Article article = new Article();
- article.setContent("Compass是第一个基于lucene的java开源框架");
- article.setTitle("学习Compass");
- article.setPublishDate(new Date());
- comSession.save(article);
- comTx.commit();
- }
public void InsertCompass()
{
CompassConfiguration comConfig = new CompassConfiguration().configure().addClass(Article.class);
Compass com = comConfig.buildCompass();
CompassSession comSession = com.openSession();
CompassTransaction comTx = comSession.beginTransaction();
Article article = new Article();
article.setContent("Compass是第一个基于lucene的java开源框架");
article.setTitle("学习Compass");
article.setPublishDate(new Date());
comSession.save(article);
comTx.commit();
}
当大家看到这里的时候就看出来Compass和Hibernate太像了。如果会Hibernate的话,学Compass将是非常容易的。
看看效果如何:
- public void LoadCompass()
- {
- CompassConfiguration comConfig = new CompassConfiguration().configure().addClass(Article.class);
- Compass com = comConfig.buildCompass();
- CompassSession comSession = com.openSession();
- CompassTransaction comTx = comSession.beginTransaction();
- Article article = (Article)comSession.load(Article.class, 0);
- System.out.println(article.getTitle());
- System.out.println(article.getContent());
- System.out.println(article.getPublishDate());
- }
public void LoadCompass()
{
CompassConfiguration comConfig = new CompassConfiguration().configure().addClass(Article.class);
Compass com = comConfig.buildCompass();
CompassSession comSession = com.openSession();
CompassTransaction comTx = comSession.beginTransaction();
Article article = (Article)comSession.load(Article.class, 0);
System.out.println(article.getTitle());
System.out.println(article.getContent());
System.out.println(article.getPublishDate());
}
结果:
学习Compass
Compass是第一个基于lucene的java开源框架
Sat Sep 23 00:51:35 CST 2006
注意:和其它的框架一样,Compass也是需要一定的配置的,而Compass的数据配置可分为Annotations,DTD验证的XML和Schema验证的XML。这里用的是dtd验证的XML配置。
我们可以用Lucene做一下检测嘛
JUnit测试用例:
- public void TestArticle() throws ParseException, IOException
- {
- QueryParser queryParser = new QueryParser("titleIndex",new StandardAnalyzer());
- Query query = queryParser.parse("compass");
- IndexSearcher indexSearcher = new IndexSearcher("target/test/index/article");
- Hits hits = indexSearcher.search(query);
- for(int i=0;i<hits.length();i++)
- {
- Document doc = hits.doc(i);
- System.out.println(doc.get("contentIndex"));//大家可以在这里设置个断点看一下doc里各个Field是什么。就会学到很多的东西
- }
- }