Compass學習文檔(1) (轉)

Compass是第一個實現java搜索引擎的開源框架,它是基於Lucene之上的，提供更簡單的搜索引擎API，事務支持，對象到搜索引擎映射（Annotations & XML），Xml到搜索引擎映射，可以和Hibernate,Spring集成，功能非常的強大。如果用Hibernate,Spring做的項目需要搜索引擎的話，Compass是個非常好的選擇。個人認爲：如果說Lucene是搜索引擎中的JDBC，那麼Compass就是Hibernate。而Compass和Hibernate不僅僅是比喻的像，它們的類和用法，和作用也非常的像。Compass是用面向對象編程方法來實現搜索。如果會Hibernate的話學Compass是非常容易的。

大家可以到http://www.opensymphony.com/compass/download.action去下載最新的版本。2006年8月28日Compass 1.1 M1 發佈，用的是Lucene2.0，現在講的就是這個版本。

雖然有人說Hibernate3.1以後版本自帶了對Lucene的支持，Compass好像沒用，但是隻要看一下Hibernate源代碼可以看出Hibernate對Lucene的支持很簡陋，且不支持事務並且Hibernate3.2用的還是Lucene版本是Lucene1.4.3，所以說當做大的項目的時候Compass還是非常有必要的。

還是先看個HelloWorld程序：（這裏的測試功能的例子都是用的JUnit測試用例，爲方便閱讀異常全部拋出）

一共4個文件Article.java， compass.cfg.xml，Article.cpm.xml，JUnit插入測試。

1.Article.java：

Java代碼

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;

    }

}

上面就是一個Article的POJO類上面有文章題目，內容，發佈時間，這裏的id的compass必須的（有點和數據庫一樣了）。

2.compass.cfg.xml

Xml代碼

<!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>
<mapping resource="org/li/compass/Article.cpm.xml"/>
</compass>
</compass-core-configuration>

<!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><!-- 這裏配置的是索引的相對路徑 -->

        <mapping resource="org/li/compass/Article.cpm.xml"/><!-- 這裏是每個對象的映射文件 -->

    </compass>

</compass-core-configuration>

這是Compass的配置文件上面標明瞭索引目錄和映射文件。映射好文件了就看看這個映射的什麼吧

3. Article.cpm.xml

Xml代碼

<!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">
<id name="id"/>
<constant>
<meta-data>type</meta-data>
<meta-data-value>java</meta-data-value>
</constant>
<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>

<!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">

        <!-- 這是必須有的 -->

        <id name="id"/>

        <!-- 你可以通過這個配置來在底層給這個對象加一個Field("type","java") -->

        <constant>

            <meta-data>type</meta-data>

            <meta-data-value>java</meta-data-value>

        </constant>

        <!-- 配置一下屬性 -->

        <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>

這個配置應該可以看的懂吧可能會有人問meta-data是幹什麼用的？？

它的值是作爲底層Field的名字，如果沒有配置的話Compass用$article/…來代替。而它的作用是配置對象的屬性的儲存形式，Compass就是讀取它來new Field()的:

Xml代碼

<!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>

<!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插入測試

Java代碼

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是第一個基於lucene的java開源框架");
article.setTitle("學習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是第一個基於lucene的java開源框架");

        article.setTitle("學習Compass");

        article.setPublishDate(new Date());

        comSession.save(article);

        comTx.commit();

    }

當大家看到這裏的時候就看出來Compass和Hibernate太像了。如果會Hibernate的話，學Compass將是非常容易的。

看看效果如何：

Java代碼

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());

    }

結果:

學習Compass

Compass是第一個基於lucene的java開源框架

Sat Sep 23 00:51:35 CST 2006

注意：和其它的框架一樣，Compass也是需要一定的配置的，而Compass的數據配置可分爲Annotations，DTD驗證的XML和Schema驗證的XML。這裏用的是dtd驗證的XML配置。

我們可以用Lucene做一下檢測嘛

JUnit測試用例：

Java代碼

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"));//大家可以在這裏設置個斷點看一下doc裏各個Field是什麼。就會學到很多的東西
}
}

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