ElasticSearch（java）创建索引-优快云博客

本文介绍如何使用Elasticsearch Java API创建索引，包括四种生成JSON文档的方法及其实现过程。此外，还提供了从Java实体类到JSON字符串的具体实例，并展示了如何通过Java API将这些JSON文档写入Elasticsearch索引。

搜索]ElasticSearch Java Api(一) －创建索引

标签： elasticsearch api java es

2016-06-19 23:25 33925人阅读评论(30) 收藏举报

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Elasticsearch（31）

目录(?)[+]

ElasticSearch Java API官网文档：https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/java-docs-index.html

一、生成JSON

创建索引的第一步是要把对象转换为JSON字符串.官网给出了四种创建JSON文档的方法：

1.1手写方式生成

String json = "{" +
        "\"user\":\"kimchy\"," + "\"postDate\":\"2013-01-30\"," + "\"message\":\"trying out Elasticsearch\"" + "}";

手写方式很简单，但是要注意日期格式：Date Formate

1.2使用集合

集合是key:value数据类型，可以代表json结构.

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

1.3使用JACKSON序列化

ElasticSearch已经使用了jackson，可以直接使用它把javabean转为json.

// instance a json mapper
ObjectMapper mapper = new ObjectMapper(); // create once, reuse

// generate json
byte[] json = mapper.writeValueAsBytes(yourbeaninstance);

1.4使用ElasticSearch 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 Elasticsearch") .endObject() String json = builder.string();

二、创建索引

下面的例子把json文档写入所以，索引库名为twitter、类型为tweet,id为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();

也可以直接传人JSON字符串：

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

可以调用response对象的方法获取返回信息：

// 索引名称
String _index = response.getIndex();
// 类型名称
String _type = response.getType();
// 文档id
String _id = response.getId();
// 版本(if it's the first time you index this document, you will get: 1) long _version = response.getVersion(); // 是否被创建is true if the document is a new one, false if it has been updated boolean created = response.isCreated();

更简单的可以直接System.out.println(response)查看返回信息.

三、java实现

新建一个Java项目，导入elasticsearch-2.3.3/lib目录下的jar文件.新建一个Blog类：

public class Blog {
    private Integer id;
    private String title;
    private String posttime; private String content; public Blog() { } public Blog(Integer id, String title, String posttime, String content) { this.id = id; this.title = title; this.posttime = posttime; this.content = content; } //setter and getter ｝

创建java实体类转json工具类：

import java.io.IOException;

import org.elasticsearch.common.xcontent.XContentBuilder; import org.elasticsearch.common.xcontent.XContentFactory; public class JsonUtil { // Java实体对象转json对象 public static String model2Json(Blog blog) { String jsonData = null; try { XContentBuilder jsonBuild = XContentFactory.jsonBuilder(); jsonBuild.startObject().field("id", blog.getId()).field("title", blog.getTitle()) .field("posttime", blog.getPosttime()).field("content",blog.getContent()).endObject(); jsonData = jsonBuild.string(); //System.out.println(jsonData); } catch (IOException e) { e.printStackTrace(); } return jsonData; } }

添加数据，返回一个list：

import java.util.ArrayList;
import java.util.Date; import java.util.List; public class DataFactory { public static DataFactory dataFactory = new DataFactory(); private DataFactory() { } public DataFactory getInstance() { return dataFactory; } public static List<String> getInitJsonData() { List<String> list = new ArrayList<String>(); String data1 = JsonUtil.model2Json(new Blog(1, "git简介", "2016-06-19", "SVN与Git最主要的区别...")); String data2 = JsonUtil.model2Json(new Blog(2, "Java中泛型的介绍与简单使用", "2016-06-19", "学习目标 掌握泛型的产生意义...")); String data3 = JsonUtil.model2Json(new Blog(3, "SQL基本操作", "2016-06-19", "基本操作：CRUD ...")); String data4 = JsonUtil.model2Json(new Blog(4, "Hibernate框架基础", "2016-06-19", "Hibernate框架基础...")); String data5 = JsonUtil.model2Json(new Blog(5, "Shell基本知识", "2016-06-19", "Shell是什么...")); list.add(data1); list.add(data2); list.add(data3); list.add(data4); list.add(data5); return list; } }

创建索引、添加数据：

import java.io.IOException;
import java.net.InetAddress; import java.net.UnknownHostException; import java.util.Date; import java.util.List; import org.elasticsearch.action.index.IndexResponse; import org.elasticsearch.client.Client; import org.elasticsearch.client.transport.TransportClient; import org.elasticsearch.common.transport.InetSocketTransportAddress; import org.elasticsearch.common.xcontent.XContentBuilder; import cn.com.bropen.entity.DataFactory; import static org.elasticsearch.common.xcontent.XContentFactory.*; public class ElasticSearchHandler { public static void main(String[] args) { try { /* 创建客户端 */ // client startup Client client = TransportClient.builder().build() .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300)); List<String> jsonData = DataFactory.getInitJsonData(); for (int i = 0; i < jsonData.size(); i++) { IndexResponse response = client.prepareIndex("blog", "article").setSource(jsonData.get(i)).get(); if (response.isCreated()) { System.out.println("创建成功!"); } } client.close(); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }