elasticsearch java api

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　　一、获取elasticsearch Client是简单的，最普遍的方法是创建连接cluster 的TransportClient。
　　注意：这个client 的版本和你在电脑上打开的服务器的主要的版本是一样的(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.>　　二、transportclient 创建
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
　　这部分描述的是增删改查。
　　单个文档的APIS有Index API ,GET API, DELETE API,DELETE BY QUERY API,UPDATE API。
　　多个文档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（别名） which points to a single index.
　　Index API
　　Index API 在特定的index中索引一个Json类型的文档。
　　创建json文件有四种方式：

• 　　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()
  

　　在内部，每种类型都转换为byte []（所以一个String被转换成一个byte []）。 因此，如果对象已经是这种形式，那么使用它。 jsonBuilder是高度优化的JSON生成器，它直接构造一个byte []。
　　Using Map
edit
　　Map is a key:values pair collection. It represents a JSON structure:
Map json = new HashMap();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>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>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();