Elasticsearch系列(八)----ES生成JSON与解析JSON的方式

一、生成JSON

四种方式如下,官网文档：https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/java-docs-index.html :

1.1手写方式生成

String json = "{" +"\"user\":\"fendo\"," +"\"postDate\":\"2013-01-30\"," +"\"message\":\"Hell word\"" +"}";

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","2013-01-30");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 mapperObjectMapper mapper = new ObjectMapper(); // create once, reuse// generate jsonbyte[] json = mapper.writeValueAsBytes(yourbeaninstance);

1.4使用ElasticSearch 帮助类

XContentBuilder builder = jsonBuilder().startObject().field("user", "kimchy").field("postDate", new Date()).field("message", "trying out Elasticsearch").endObject() String json = builder.string();

完整示例:

package com.fendo.temp;import java.io.IOException;import java.net.InetAddress;import java.net.UnknownHostException;import java.util.Date;import java.util.HashMap;import java.util.Map;import org.elasticsearch.action.index.IndexResponse;import org.elasticsearch.client.transport.TransportClient;import org.elasticsearch.common.settings.Settings;import org.elasticsearch.common.transport.InetSocketTransportAddress;import org.elasticsearch.common.xcontent.XContentBuilder;import org.elasticsearch.common.xcontent.XContentFactory;import org.elasticsearch.transport.client.PreBuiltTransportClient;import org.junit.Before;import org.junit.Test;import com.fasterxml.jackson.core.JsonProcessingException;import com.fasterxml.jackson.databind.ObjectMapper;public class CreateIndex {private TransportClient client;@Beforepublic void getClient() throws Exception{        //设置集群名称        Settings settings = Settings.builder().put("cluster.name", "my-application").build();// 集群名        //创建client        client  = new PreBuiltTransportClient(settings)                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));}/** * 手动生成JSON */@Testpublic void CreateJSON(){String json = "{" +        "\"user\":\"fendo\"," +        "\"postDate\":\"2013-01-30\"," +        "\"message\":\"Hell word\"" +    "}";IndexResponse response = client.prepareIndex("fendo", "fendodate")        .setSource(json)        .get();System.out.println(response.getResult());}/** * 使用集合 */@Testpublic void CreateList(){Map<String, Object> json = new HashMap<String, Object>();json.put("user","kimchy");json.put("postDate","2013-01-30");json.put("message","trying out Elasticsearch");IndexResponse response = client.prepareIndex("fendo", "fendodate")        .setSource(json)        .get();System.out.println(response.getResult());}/** * 使用JACKSON序列化 * @throws Exception */@Testpublic void CreateJACKSON() throws Exception{CsdnBlog csdn=new CsdnBlog();csdn.setAuthor("fendo");csdn.setContent("这是JAVA书籍");csdn.setTag("C");csdn.setView("100");csdn.setTitile("编程");csdn.setDate(new Date().toString());// instance a json mapperObjectMapper mapper = new ObjectMapper(); // create once, reuse// generate jsonbyte[] json = mapper.writeValueAsBytes(csdn);IndexResponse response = client.prepareIndex("fendo", "fendodate")        .setSource(json)        .get();System.out.println(response.getResult());}/** * 使用ElasticSearch 帮助类 * @throws IOException  */@Testpublic void CreateXContentBuilder() throws IOException{XContentBuilder builder = XContentFactory.jsonBuilder()    .startObject()        .field("user", "ccse")        .field("postDate", new Date())        .field("message", "this is Elasticsearch")    .endObject();        IndexResponse response = client.prepareIndex("fendo", "fendodata").setSource(builder).get();        System.out.println("创建成功!");        }}

二、解析JSON

Jest对获取的JSON数据,有两种解析方式

1、手动解析

   /**     * 手动解析     * @throws IOException      */    @Test    public void ManualOperation() throws IOException{        int pageNumber=1;    int pageSize=10;        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();    searchSourceBuilder.query(QueryBuilders.queryStringQuery("JAVA"));    searchSourceBuilder.from((pageNumber - 1) * pageSize);//设置起始页        searchSourceBuilder.size(pageSize);//设置页大小        Search search = new Search.Builder(searchSourceBuilder.toString())                .addIndex(indexName)// 索引名称                .build();        SearchResult result = jestClient.execute(search);                                // 手动解析        JsonObject jsonObject = result.getJsonObject();        JsonObject hitsobject = jsonObject.getAsJsonObject("hits");        long took = jsonObject.get("took").getAsLong();        long total = hitsobject.get("total").getAsLong();        JsonArray jsonArray = hitsobject.getAsJsonArray("hits");                System.out.println("took:"+took+"  "+"total:"+total);                List<CsdnBlog> csdnBlogs=new ArrayList<CsdnBlog>();                 for (int i = 0; i < jsonArray.size(); i++) {            JsonObject jsonHitsObject = jsonArray.get(i).getAsJsonObject();            // 获取返回字段            JsonObject sourceObject = jsonHitsObject.get("_source").getAsJsonObject();            // 封装Article对象            CsdnBlog article = new CsdnBlog();            article.setTitile(sourceObject.get("titile").getAsString());            article.setContent(sourceObject.get("content").getAsString());            article.setAuthor(sourceObject.get("author").getAsString());            article.setDate(sourceObject.get("date").getAsString());            article.setTag(sourceObject.get("tag").getAsString());            article.setView(sourceObject.get("view").getAsString());            csdnBlogs.add(article);                  }             System.out.println(csdnBlogs.size());            }

2、自动解析:

   /**     * 自动解析     * @throws Exception     */    @Test    public void Auto() throws Exception{            int pageNumber=1;    int pageSize=10;        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();    searchSourceBuilder.query(QueryBuilders.queryStringQuery("JAVA"));    searchSourceBuilder.from((pageNumber - 1) * pageSize);//设置起始页        searchSourceBuilder.size(pageSize);//设置页大小        Search search = new Search.Builder(searchSourceBuilder.toString())                .addIndex(indexName)// 索引名称                .build();        SearchResult result = jestClient.execute(search);                        // 自动解析        JsonObject jsonObject = result.getJsonObject();        JsonObject hitsobject = jsonObject.getAsJsonObject("hits");        long took = jsonObject.get("took").getAsLong();        long total = hitsobject.get("total").getAsLong();                System.out.println("took:"+took+"  "+"total:"+total);                List<SearchResult.Hit<CsdnBlog, Void>> hits = result.getHits(CsdnBlog.class);                List<CsdnBlog> csdnBlogs=new ArrayList<CsdnBlog>();         for (SearchResult.Hit<CsdnBlog, Void> hit : hits) {                CsdnBlog source = hit.source;        csdnBlogs.add(source);                }        System.out.println(csdnBlogs.size());            }