elasticsearch 自定義similarity 插件開發

轉自:http://www.chepoo.com/elasticsearch-similarity-custom-plug-in-development.html

 

在搜索開發中，咱們要修改打分機制，就須要自定義similarity。如今來簡單說一下elasticsearch下的自定義similarity 插件開發。

網上的https://github.com/tlrx/elasticsearch-custom-similarity-provider僅僅支持0.20.0.Beta1-SNAPSHOT版本，如今咱們用的版本是elasticsearch 0.90版本以上。那個例子如今不能用，我修改了一下。

1.繼承DefaultSimilarity，實現本身的搜索打分機制。

package org.elasticsearch.index.similarity; import org.apache.lucene.search.similarities.DefaultSimilarity; /** * Custom similarity class * * @author xq * */ public class CustomSimilarity extends DefaultSimilarity { @Override public float idf(long docFreq, long numDocs) { return 1.0f; } }

2.繼續AbstractSimilarityProvider，把自定義的打分機制類加載到elasticsearch中。

package org.elasticsearch.index.similarity; import org.elasticsearch.common.inject.Inject; import org.elasticsearch.common.inject.assistedinject.Assisted; import org.elasticsearch.common.settings.Settings; /** * Simple {@link SimilarityProvider} for a {@link CustomSimilarity} * * @author xq * */ public class CustomSimilarityProvider extends AbstractSimilarityProvider { private CustomSimilarity similarity; @Inject public CustomSimilarityProvider(@Assisted String name, @Assisted Settings settings) { super(name); this.similarity = new CustomSimilarity(); } public CustomSimilarity get() { return similarity; } }

3.繼承AbstractPlugin做爲elasticsearch插件使用

public class CustomerSimilarityPlugin extends AbstractPlugin { @Override public String name() { return "customer-similarity"; } @Override public String description() { return "customer similarity"; } @Override public void processModule(Module module) { if (module instanceof SimilarityModule) { SimilarityModule similarityModule = (SimilarityModule) module; similarityModule.addSimilarity("customer-similarity", CustomSimilarityProvider.class); } } }

4.使用

curl -XPOST 'http://host:port/tweeter/' -d ' { "settings": { "similarity": { "index": { "type": "org.elasticsearch.index.similarity.CustomSimilarityProvider" }, "search": { "type": "org.elasticsearch.index.similarity.CustomSimilarityProvider" } } } }'

在建立mapping的使用自定義的打分規則：

{ "news" : { "properties" : { "title" : { "type" : "string", "similarity" : "my_similarity" } } }

在elasticsearch.yml中配置自定義的打分規則類爲默認規則。 index.similarity.default.type: my_similarity

相關程序已經放在https://github.com/awnuxkjy/es-custom-similarity-provider,有興趣的朋友能夠參考一下。

把程序打成jar包放在elasticsearch 的plugins 下的 similarity 目錄下便可 參考文章： http://www.elasticsearch.org/guide/reference/index-modules/similarity/