elasticsearch java api

一、獲取elasticsearch Client是簡單的，最普遍的方法是創建連接cluster 的TransportClient。

注意：這個client 的版本和你在電腦上打開的服務器的主要的版本是一樣的(e.g. 2.x, or 5.x) 

The client must have the same major version (e.g. 2.x, or 5.x) as the nodes in the cluster. Clients may connect to clusters which have a different minor version (e.g.2.3.x) but it is possible that new functionality may not be supported. Ideally, the client should have the same version as the cluster.

二、transportclient 創建

TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("host1"), 9300))
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("host2"), 9300));

// on shutdown

client.close();

Note that you have to set the cluster name if you use one different than "elasticsearch":

Settings settings = Settings.builder()
        .put("cluster.name", "myClusterName").build();
TransportClient client = new PreBuiltTransportClient(settings);
//Add transport addresses and do something with the client...

三、Document  APIS

這部分描述的是增刪改查。

單個文檔的APIS有Index API ,GET API, DELETE API,DELETE BY QUERY API,UPDATE API。

多個文檔APIS 有：Multi Get API ,Bulk API

注意：All CRUD APIs are single-index APIs. The index parameter accepts a single index name, or an alias（別名） which points to a single index.

Index API 

Index API 在特定的index中索引一個Json類型的文檔。

創建json文件有四種方式：

• Manually （手工）(aka do it yourself) using native byte[] or as a String

• Using a Map that will be automatically converted to its JSON equivalent（相等的）

• Using a third party library to serialize your beans such as Jackson

• Using built-in helpers XContentFactory.jsonBuilder()

在內部，每種類型都轉換爲byte []（所以一個String被轉換成一個byte []）。 因此，如果對象已經是這種形式，那麼使用它。 jsonBuilder是高度優化的JSON生成器，它直接構造一個byte []。

Using Map

edit

Map is a key:values pair collection. It represents a JSON structure:

Map<String, Object> json = new HashMap<String, Object>();json.put("user","kimchy");json.put("postDate",new Date());json.put("message","trying out Elasticsearch");

Use Elasticsearch helpersedit

Elasticsearch provides built-in helpers to generate JSON content.

import static org.elasticsearch.common.xcontent.XContentFactory.*;XContentBuilder builder = jsonBuilder()
    .startObject()
        .field("user", "kimchy")
        .field("postDate", new Date())
        .field("message", "trying out Elasticsearch")
    .endObject()

Index documentedit

The following example indexes a JSON document into an index called twitter, under a type called tweet, with id valued 1:

import static org.elasticsearch.common.xcontent.XContentFactory.*;IndexResponse response = client.prepareIndex("twitter", "tweet", "1")
        .setSource(jsonBuilder()
                    .startObject()
                        .field("user", "kimchy")
                        .field("postDate", new Date())
                        .field("message", "trying out Elasticsearch")
                    .endObject()
                  )
        .get();

Note that you can also index your documents as JSON String and that you don’t have to give an ID:

String json = "{" +
        "\"user\":\"kimchy\"," +
        "\"postDate\":\"2013-01-30\"," +
        "\"message\":\"trying out Elasticsearch\"" +
    "}";IndexResponse response = client.prepareIndex("twitter", "tweet")
        .setSource(json)
        .get();

IndexResponse object will give you a report:

// Index nameString _index = response.getIndex();// Type nameString _type = response.getType();// Document ID (generated or not)String _id = response.getId();// Version (if it's the first time you index this document, you will get: 1)long _version = response.getVersion();// status has stored current instance statement.RestStatus status = response.status();