标签： elasticsearchapijavaes

2016-06-19 23:25 33925人阅读 评论(30) 收藏 举报

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Elasticsearch（31） 

ElasticSearch JavaAPI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();

        }

    }

}

查看插入的数据： 

2016.12.12 日更新

使用5.X版本的移步到这里：Elasticsearch 5.0下Java API使用指南