elasticsearch java API -目录数据
创建索引的第一步工作,是将你要创建索引的对象转化为Json字符串。
生成Json的方法很多,最直接的是手写,将你的实体转化为Json:
- String json = "{" +
- ""user":"kimchy"," +
- ""postDate":"2013-01-30"," +
- ""message":"trying out Elastic Search"," +
- "}";
第二种,是使用Map方式:
- Map<String, Object> json = new HashMap<String, Object>();
- json.put("user","kimchy");
- json.put("postDate",new Date());
- json.put("message","trying out Elastic Search");
第三种,是使用Elasticsearch提供的帮助类
- import static org.elasticsearch.common.xcontent.XContentFactory.*;
- XContentBuilder builder = jsonBuilder()
- .startObject()
- .field("user", "kimchy")
- .field("postDate", new Date())
- .field("message", "trying out Elastic Search")
- .endObject();
- String json = builder.string();
第四种是使用jackson技术,你可以导入jackson的jar包,如果是maven管理的项目,则直接在pom.xml中添加:
- <dependency>
- <groupId>com.fasterxml.jackson.core</groupId>
- <artifactId>jackson-databind</artifactId>
- <version>2.1.3</version>
- </dependency>
然后:
- import com.fasterxml.jackson.databind.*;
- // instance a json mapper
- ObjectMapper mapper = new ObjectMapper(); // create once, reuse
- // generate json
- String json = mapper.writeValueAsString(yourbeaninstance);
接下来便可以创建索引了:
- IndexResponse response = client.prepareIndex("twitter", "tweet")
- .setSource(json)
- .execute()
- .actionGet();
client.prepareIndex的参数可以是0个(其后必须使用index(String)和type(String)方法),两个(client.prepareIndex(index,type))和三个(client.prepareIndex(index,type,id)),其中,index类似于数据库名,type类似于表名,而id则是每条记录的惟一编码,通常情况下,我们会把实体的惟一编码作为ES的ID,当然,不给的时候,由ES自动生成。
response是Elasticsearch创建完成索引后,回馈给你的实体,你可以从这个实体中获得一些有价值的信息:
- // 索引名称
- String _index = response.index();
- // type名称
- String _type = response.type();
- // 文档ID
- String _id = response.id();
- // 索引版本
- long _version = response.version();
TransportClient client = null;
public ESClientTest() {
Settings settings = ImmutableSettings.settingsBuilder()
.put("client.transport.sniff", true).build();
client = new TransportClient(settings);
}
public void connect() {
client.addTransportAddress(new InetSocketTransportAddress("localhost", 9300));
}
public void close(){
client.close();
}
public void index(){
try {
XContentBuilder doc = XContentFactory.jsonBuilder()
.startObject()
.field("title", "this")
.field("description", "descript")
.field("price", 100)
.field("onSale", true)
.field("type", 1)
.field("createDate", new Date())
.endObject();
client.prepareIndex("productindex","productindex","1").setSource(doc).execute().actionGet();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
ESClientTest es = new ESClientTest();
es.index();
es.close();
}
其中productIndex为索引库名,一个es集群中可以有多个索引库。productType为索引类型,是用来区分同索引库下不同类型的数据的,一个索引库下可以有多个索引类型。
elasticsearch java API --------删除索引数据
public void delbyquery(){
QueryBuilder query = QueryBuilders.fieldQuery("type", "1");
client.prepareDeleteByQuery("productindex").setQuery(query).execute().actionGet();
}
public void delbyid(){
DeleteResponse response = client.prepareDelete("productindex", "productindex", "1")
.execute()
.actionGet();
}