[大数据]ElasticSearch编程--基本的创建与查询操作

创建测试项目，导包

创建一个maven项目，导入ElasticSearch相关包

    <dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>5.6.8</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>5.6.8</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-to-slf4j</artifactId>
            <version>2.9.1</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.24</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.21</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

创建索引

    @Test
    //创建索引
    public void createIndex() throws Exception{
        //1.设置加入的集群
        Settings settings = Settings.builder().put("cluster.name","my-elasticsearch").build();
        //2.创建client连接对象
        TransportClient client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.111.129"),9300));
        //3.创建名称为blog2的索引
        client.admin().indices().prepareCreate("blog2").get();
        //4.释放资源
        client.close();
    }

运行结果可以在elasticsearch-head-master中看到

创建映射mapping

因为无论创建索引还是mapping，以及之后的创建数据和查询操作都需要创建client连接对象，所以我们将其封装成一个单独的方法。此处注解Before的作用为在点击运行test之前都会限制行一遍getTransportClient()方法

    TransportClient client ;

    @Before
    public void getTransportClient() throws UnknownHostException {
        Settings settings = Settings.builder().put("cluster.name","my-elasticsearch").build();
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.111.129"), 9300));
    }

创建映射

    @Test
    //创建映射
    public void createMappings() throws Exception {

        //添加映射
        /**
        "mappings": {
            "article": {
                "properties": {
                    "id": {
                        "store": true,
                        "type": "integer"
                    },
                    "title": {
                        "analyzer": "ik_smart",
                        "store": true,
                        "type": "text"
                    },
                    "content": {
                        "analyzer": "ik_smart",
                        "store": true,
                        "type": "text"
                    }
                }
            }
         }
         */

        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .startObject("article")
                .startObject("properties")
                .startObject("id")
                .field("type","integer").field("store","yes")
                .endObject()
                .startObject("title")
                .field("type","string").field("store","yes").field("analyzer","ik_smart")
                .endObject()
                .startObject("content")
                .field("type","string").field("store","yes").field("analyzer","ik_smart")
                .endObject()
                .endObject()
                .endObject()
                .endObject();

        //创建映射
        PutMappingRequest mapping = Requests.putMappingRequest("blog2")
                .type("article").source(builder);
        client.admin().indices().putMapping(mapping).get();
        //释放资源
        client.close();
    }

运行后可以在elasticsearch-head-master中看到

建立文档操作

建立文档1–通过XContentBuilder

此处要注意id格式默认为长整型

    @Test
    //建立文档--通过XContentBuilder
    public void  createDoc() throws Exception{
        //创建client对象
        //创建一个文档对象
        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .field("id", 2L)
                .field("title","桂林大暴雨")
                .field("content","桂林下雨了！桂林又下雨了！")
                .endObject();
        //把文档对象添加到索引库
        client.prepareIndex()
                //设置索引名称
                .setIndex("blog2")
                //设置type
                .setType("article")
                //设置文档的id,如果不设置的话自动生成一个id
                .setId("2")
                //设置文档信息
                .setSource(builder)
                //执行操作
                .get();
        //关闭客户端
        client.close();
        
    }

可以在elasticsearch-head-master中看到

建立文档2–通过Jackson转换实体

字面意思通过传入对象的方式创建文档
首先创建Article实体类

public class Article {
    private long id;
    private String title;
    private String content;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

然后使?Jackson转换实体

    @Test
    //创建文档第二种方式--通过ackson转换实体
    public void createDoc2() throws Exception{
        //创建一个Article对象
        Article article = new Article();
        //设置对象的属性
        article.setId(3);
        article.setTitle("桂林大暴雪");
        article.setContent("这是不可能的！这是不可能的！");
        //把article对象转换成json格式的字符串
        ObjectMapper objectMapper = new ObjectMapper();
        String jsonDocument = objectMapper.writeValueAsString(article);
        System.out.println(jsonDocument);
        //使用client对象把文档写入索引库
        client.prepareIndex("blog2","article","3")
                .setSource(jsonDocument, XContentType.JSON)
                .get();
        //关闭客户端
    }

同样可以在elasticsearch-head-master中看到，文档同样创建成功

查询文档操作

TermQuery

TermQuery：对搜索的关键词不分词

	@Test
    //termQuery查询
    public void testQueryByTerm() throws Exception{
        //创建一个QueryBuilder对象
        //参数1:要搜索的字段
        //参数2:要搜索的关键词
        QueryBuilder queryBuilder = QueryBuilders.termQuery("title","桂林暴雪");
        //执行查询
        SearchResponse searchResponse = client.prepareSearch("blog2")
                .setTypes("article")
                .setQuery(queryBuilder)
                .get();
        //得到查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果的总记录数
        System.out.println("查询结果总记录数:"+searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while(iterator.hasNext()) {
            SearchHit searchHit = iterator.next();
            //打印?档对象，以json格式输出
            System.out.println(searchHit.getSourceAsString());
            //取?档的属性
            System.out.println("-----------?档的属性-----------");
            Map<String, Object> document = searchHit.getSource();
            System.out.println(document.get("id"));
            System.out.println(document.get("title"));
            System.out.println(document.get("content"));
        }
        //关闭client
        client.close();

    }

QueryString

query_string：搜索之前对搜索的关键词分词,搜索结果取决于分词器

@Test
    public void testQueryByQueryString() throws Exception {
        //创建?个QueryBuilder对象
        //参数1：要搜索的字段
        //参数2：要搜索的关键词
        QueryBuilder queryBuilder = QueryBuilders.queryStringQuery("桂林暴雪").defaultField("title");
                //执?查询
                SearchResponse searchResponse = client.prepareSearch("blog2")
                        .setTypes("article")
                        .setQuery(queryBuilder)
                        .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果的总记录数
        System.out.println("查询结果总记录数：" + searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while(iterator.hasNext()) {
            SearchHit searchHit = iterator.next();
            //打印?档对象，以json格式输出
            System.out.println(searchHit.getSourceAsString());
            //取?档的属性
            System.out.println("-----------?档的属性-----------");
            Map<String, Object> document = searchHit.getSource();
            System.out.println(document.get("id"));
            System.out.println(document.get("title"));
            System.out.println(document.get("content"));
        }
        //关闭client
        client.close();
    }

MatchQuery

match查询时，对查询字符串会进行分词处理。

 @Test
    public void testQueryByMatchQuery() throws Exception {
        //创建?个QueryBuilder对象
        //参数1：要搜索的字段
        //参数2：要搜索的关键词
        QueryBuilder queryBuilder = QueryBuilders.matchQuery("title", "桂暴雪");
                //执?查询
                SearchResponse searchResponse = client.prepareSearch("blog2")
                        .setTypes("article")
                        .setQuery(queryBuilder)
                        .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果的总记录数
        System.out.println("查询结果总记录数：" + searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while(iterator.hasNext()) {
            SearchHit searchHit = iterator.next();
            //打印?档对象，以json格式输出
            System.out.println(searchHit.getSourceAsString());
            //取?档的属性
            System.out.println("-----------?档的属性-----------");
            Map<String, Object> document = searchHit.getSource();
            System.out.println(document.get("id"));
            System.out.println(document.get("title"));
            System.out.println(document.get("content"));
        }
        //关闭client
        client.close();
    }

查询后分页

 //查询后分页方法
    private void search(QueryBuilder queryBuilder) throws Exception {
        //执?查询
        SearchResponse searchResponse = client.prepareSearch("blog2")
                .setTypes("article")
                .setQuery(queryBuilder)
                //设置分?信息
                .setFrom(0)
                //每?显示的?数
                .setSize(5)
                .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果的总记录数
        System.out.println("查询结果总记录数：" + searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while(iterator.hasNext()) {
            SearchHit searchHit = iterator.next();
            //打印?档对象，以json格式输出
            System.out.println(searchHit.getSourceAsString());
            //取?档的属性
            System.out.println("-----------?档的属性");
            Map<String, Object> document = searchHit.getSource();
            System.out.println(document.get("id"));
            System.out.println(document.get("title"));
            System.out.println(document.get("content"));
        }
        //关闭client
        client.close();
    }

使用文档id查询

//使用文档ID查询文档
    @Test
    public void testSearchById() throws Exception {
        //创建?个client对象
        //创建?个查询对象
        QueryBuilder queryBuilder = QueryBuilders.idsQuery().addIds("2", "3");
        search(queryBuilder);
    }

查询结果高亮操作

比如在京东商城搜索“笔记本”

通过开发者?具查看?亮数据的html代码实现：

ElasticSearch可以对查询出的内容中关键字部分进?标签和样式的设置，但是你需要告诉ElasticSearch
使?什么标签对?亮关键字进?包裹

代码实现如下：

//高亮代码实现
    @Test
    public void highlightSearchTest() throws Exception {
        QueryBuilder queryBuilder = QueryBuilders.multiMatchQuery("桂林", "title", "content");
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        highlightBuilder.field("title").field("content");
        highlightBuilder.preTags("<em>");
        highlightBuilder.postTags("</em>");
        //执?查询
        SearchResponse searchResponse = client.prepareSearch("blog2")
                .setTypes("article")
                .setQuery(queryBuilder)
                //设置?亮信息
                .highlighter(highlightBuilder)
                .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果的总记录数
        System.out.println("查询结果总记录数：" + searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while(iterator.hasNext()) {
            SearchHit searchHit = iterator.next();
            //取?档的属性
            System.out.println("-----------?档的属性-----------");
            Map<String, Object> document = searchHit.getSource();
            System.out.println(document.get("id"));
            System.out.println(document.get("title"));
            System.out.println(document.get("content"));
            System.out.println("************高亮结果************");
            Map<String, HighlightField> highlightFields =
                    searchHit.getHighlightFields();
            //取title?亮显示的结果
            if (highlightFields.size() <=0) continue;
            for (Map.Entry<String, HighlightField> entry :
                    highlightFields.entrySet()) {
                System.out.println(entry.getKey() + ":\t" +
                        Arrays.toString(entry.getValue().getFragments()));
            }
        }
        //关闭client
        client.close();
    }

查询结果如下

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