从Java读取ElasticSearch索引 [英] Read ElasticSearch Index from Java
问题描述
我正在尝试从Java程序中读取 ElasticSearch (1.4)索引,但是我真的不知道从哪里开始.
I'm trying to read an ElasticSearch (1.4) index from a Java program, but I don't really have an idea where to start.
我没有正在运行的ES实例,因此无法使用常规" API.
I don't have a running ES instance so I cannot use the "normal" API.
我了解的是,acual索引文件是 Lucene ,因此必须有一种读取它们的方法.性能不是问题,因此我不介意程序运行时间更长(甚至整夜).
What I understand is the acual index files are Lucene so there must be a way to read them. Performance is not an issue, so I don't mind if the program runs a little longer (or even all night).
推荐答案
是的,您是正确的 Elasticsearch 索引(在一个分片上),只是正常的 Lucene 索引,因此使用 Lucene 在Java程序中打开它真的很容易.
Yes, you're right Elasticsearch index (on one shard) just a normal Lucene index, so it's really easy to open it in Java program using Lucene.
最简单的方法如下:
IndexReader reader = DirectoryReader.open(FSDirectory.open(Paths.get(INDEX_PATH)));
IndexSearcher searcher = new IndexSearcher(reader);
它是 Lucene 5.0 ,但是 Lucene 4.xx 与此类似:
IndexReader reader = IndexReader.open(FSDirectory.open(new File(INDEX_PATH)), true);
IndexSearcher searcher = new IndexSearcher(reader);
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