ElasticSearch专题(七)-JAVA客户端

1.本章目标

1. 能够使用java客户端完成创建、删除索引的操作
2. 能够使用java客户端完成文档的增删改的操作
3. 能够使用java客户端完成文档的查询操作
4. 能够完成文档的分页操作
5. 能够完成文档的高亮查询操作

2.创建工程，导入坐标

pom.xml坐标

 <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>

3.创建索引index

 @Test
 //创建索引
 public void test1() throws Exception {
     // 创建Client连接对象
     Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
     TransportClient client = new PreBuiltTransportClient(settings).addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
     //创建名称为blog2的索引
     client.admin().indices().prepareCreate("blog2").get();
     //释放资源
     client.close();
     System.out.println("blog2索引库创建成功！");
 }

4.创建映射mapping

@Test
//创建映射
public void test3() throws Exception{
    // 创建Client连接对象
    Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
    TransportClient client = new PreBuiltTransportClient(settings)
            .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

    // 添加映射
    /**
     * 格式：
     * "mappings" : {
     "article" : {
     "dynamic" : "false",
     "properties" : {
     "id" : { "type" : "string" },
     "content" : { "type" : "string" },
     "author" : { "type" : "string" }
     }
     }
     }
     */
    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();
    System.out.println("blog2创建Mapping创建成功！");
}

5.建立文档document

5.1.建立文档（通过XContentBuilder）

@Test
//创建文档(通过XContentBuilder)
public void test4() throws Exception {
    // 创建Client连接对象
    Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
    TransportClient client = new PreBuiltTransportClient(settings)
            .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

    //创建文档信息
    XContentBuilder builder = XContentFactory.jsonBuilder()
            .startObject()
            .field("id", 1)
            .field("title", "ElasticSearch是一个基于Lucene的搜索服务器")
            .field("content",
                    "它提供了一个分布式多用户能力的全文搜索引擎，基于RESTful web接口。Elasticsearch是用Java开发的，并作为Apache许可条款下的开放源码发布，是当前流行的企业级搜索引擎。设计用于云计算中，能够达到实时搜索，稳定，可靠，快速，安装使用方便。")
            .endObject();

    // 建立文档对象
    /**
     * 参数一blog1：表示索引对象
     * 参数二article：类型
     * 参数三1：建立id
     */
    client.prepareIndex("blog2", "article", "1").setSource(builder).get();

    //释放资源
    client.close();
}

5.2.建立文档（使用Jackson转换实体）

1）创建Article实体

/**
 * @Auther: bruceliu
 * @Date: 2019/12/2 23:06
 * @QQ:1241488705
 * @Description:
 */
public class Article {

    private Integer id;
    private String title;
    private String content;

    public Article(Integer id, String title, String content) {
        this.id = id;
        this.title = title;
        this.content = content;
    }

    public Article() {
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }

    @Override
    public String toString() {
        return "Article{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", content='" + content + '\'' +
                '}';
    }
}

2）添加jackson坐标

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.8.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.8.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.8.1</version>
</dependency>

3）代码实现

@Test
//创建文档(通过实体转json)
public void test5() throws Exception{
    // 创建Client连接对象
    Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
    TransportClient client = new PreBuiltTransportClient(settings)
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

    // 描述json 数据
    //{id:xxx, title:xxx, content:xxx}
    Article article = new Article();
    article.setId(2);
    article.setTitle("搜索工作其实很快乐");
    article.setContent("我们希望我们的搜索解决方案要快，我们希望有一个零配置和一个完全免费的搜索模式，我们希望能够简单地使用JSON通过HTTP的索引数据，我们希望我们的搜索服务器始终可用，我们希望能够一台开始并扩展到数百，我们要实时搜索，我们要简单的多租户，我们希望建立一个云的解决方案。Elasticsearch旨在解决所有这些问题和更多的问题。");

    ObjectMapper objectMapper = new ObjectMapper();

    // 建立文档
    client.prepareIndex("blog2", "article", article.getId().toString())
        //.setSource(objectMapper.writeValueAsString(article)).get();
        .setSource(objectMapper.writeValueAsString(article).getBytes(), XContentType.JSON).get();

    //释放资源
    client.close();
}

6.查询文档操作

6.1.关键词查询

@Test
 public void testTermQuery() throws Exception{
     //1、创建es客户端连接对象
     Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
     TransportClient client = new PreBuiltTransportClient(settings)
             .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

     //2、设置搜索条件
     SearchResponse searchResponse = client.prepareSearch("blog2")
             .setTypes("article")
             .setQuery(QueryBuilders.termQuery("content", "搜索")).get();

     //3、遍历搜索结果数据
     SearchHits hits = searchResponse.getHits(); // 获取命中次数，查询结果有多少对象
     System.out.println("查询结果有：" + hits.getTotalHits() + "条");
     Iterator<SearchHit> iterator = hits.iterator();
     while (iterator.hasNext()) {
         SearchHit searchHit = iterator.next(); // 每个查询对象
         System.out.println(searchHit.getSourceAsString()); // 获取字符串格式打印
         System.out.println("title:" + searchHit.getSource().get("title"));
     }
     //4、释放资源
     client.close();
 }

6.2.字符串查询

 @Test
public void testStringQuery() throws Exception{
    //1、创建es客户端连接对象
    Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
    TransportClient client = new PreBuiltTransportClient(settings)
            .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

    //2、设置搜索条件
    SearchResponse searchResponse = client.prepareSearch("blog2")
            .setTypes("article")
            .setQuery(QueryBuilders.queryStringQuery("搜索")).get();

    //3、遍历搜索结果数据
    SearchHits hits = searchResponse.getHits(); // 获取命中次数，查询结果有多少对象
    System.out.println("查询结果有：" + hits.getTotalHits() + "条");
    Iterator<SearchHit> iterator = hits.iterator();
    while (iterator.hasNext()) {
        SearchHit searchHit = iterator.next(); // 每个查询对象
        System.out.println(searchHit.getSourceAsString()); // 获取字符串格式打印
        System.out.println("title:" + searchHit.getSource().get("title"));
    }

    //4、释放资源
    client.close();

}

6.3.使用文档ID查询文档

 @Test
public void testIdQuery() throws Exception {
     Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
     TransportClient client = new PreBuiltTransportClient(settings)
             .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
     //client对象为TransportClient对象
     SearchResponse response = client.prepareSearch("blog1")
             .setTypes("article")
             //设置要查询的id
             .setQuery(QueryBuilders.idsQuery().addIds("1"))
             //执行查询
             .get();
     //取查询结果
     SearchHits searchHits = response.getHits();
     //取查询结果总记录数
     System.out.println(searchHits.getTotalHits());
     Iterator<SearchHit> hitIterator = searchHits.iterator();
     while(hitIterator.hasNext()) {
         SearchHit searchHit = hitIterator.next();
         //打印整行数据
         System.out.println(searchHit.getSourceAsString());
     }

7.查询文档分页操作

7.1 批量插入数据

@Test
//批量插入100条数据
public void test9() throws Exception{
    	// 创建Client连接对象
        Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
        TransportClient client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

        ObjectMapper objectMapper = new ObjectMapper();

        for (int i = 1; i <= 100; i++) {
            // 描述json 数据
            Article article = new Article();
            article.setId(i);
            article.setTitle(i + "搜索工作其实很快乐");
            article.setContent(i
                    + "我们希望我们的搜索解决方案要快，我们希望有一个零配置和一个完全免费的搜索模式，我们希望能够简单地使用JSON通过HTTP的索引数据，我们希望我们的搜索服务器始终可用，我们希望能够一台开始并扩展到数百，我们要实时搜索，我们要简单的多租户，我们希望建立一个云的解决方案。Elasticsearch旨在解决所有这些问题和更多的问题。");

            // 建立文档
            client.prepareIndex("blog2", "article", article.getId().toString())
                    //.setSource(objectMapper.writeValueAsString(article)).get();
                    .setSource(objectMapper.writeValueAsString(article).getBytes(),XContentType.JSON).get();
        }

        //释放资源
        client.close();
}

7.2 分页查询

 @Test
    //分页查询
    public void test10() throws Exception{
        // 创建Client连接对象
        Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
        TransportClient client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

        // 搜索数据
        SearchRequestBuilder searchRequestBuilder = client.prepareSearch("blog2").setTypes("article")
                .setQuery(QueryBuilders.matchAllQuery());//默认每页10条记录

        // 查询第2页数据，每页20条
        //setFrom()：从第几条开始检索，默认是0。
        //setSize():每页最多显示的记录数。
        searchRequestBuilder.setFrom(0).setSize(5);
        SearchResponse searchResponse = searchRequestBuilder.get();

        SearchHits hits = searchResponse.getHits(); // 获取命中次数，查询结果有多少对象
        System.out.println("查询结果有：" + hits.getTotalHits() + "条");
        Iterator<SearchHit> iterator = hits.iterator();
        while (iterator.hasNext()) {
            SearchHit searchHit = iterator.next(); // 每个查询对象
            System.out.println(searchHit.getSourceAsString()); // 获取字符串格式打印
            System.out.println("id:" + searchHit.getSource().get("id"));
            System.out.println("title:" + searchHit.getSource().get("title"));
            System.out.println("content:" + searchHit.getSource().get("content"));
            System.out.println("-----------------------------------------");
        }

        //释放资源
        client.close();
    }

8.什么是高亮显示

在进行关键字搜索时，搜索出的内容中的关键字会显示不同的颜色，称之为高亮

百度搜索关键字"Java搜索引擎"

京东商城搜索"笔记本"

8.1.高亮显示的html分析

通过开发者工具查看高亮数据的html代码实现：

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

8.2. 高亮显示代码实现

@Test
//高亮查询
public void test11() throws Exception{
    // 创建Client连接对象
    Settings settings = Settings.builder().put("cluster.name", "my-elasticsearch").build();
    TransportClient client = new PreBuiltTransportClient(settings)
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

    // 搜索数据
    SearchRequestBuilder searchRequestBuilder = client
        .prepareSearch("blog2").setTypes("article")
        .setQuery(QueryBuilders.termQuery("title", "搜索"));

    //设置高亮数据
    HighlightBuilder hiBuilder=new HighlightBuilder();
    hiBuilder.preTags("<font style='color:red'>");
    hiBuilder.postTags("</font>");
    hiBuilder.field("title");
    searchRequestBuilder.highlighter(hiBuilder);

    //获得查询结果数据
    SearchResponse searchResponse = searchRequestBuilder.get();

    //获取查询结果集
    SearchHits searchHits = searchResponse.getHits();
    System.out.println("共搜到:"+searchHits.getTotalHits()+"条结果!");
    //遍历结果
    for(SearchHit hit:searchHits){
        System.out.println("String方式打印文档搜索内容:");
        System.out.println(hit.getSourceAsString());
        System.out.println("Map方式打印高亮内容");
        System.out.println(hit.getHighlightFields());

        System.out.println("遍历高亮集合，打印高亮片段:");
        Text[] text = hit.getHighlightFields().get("title").getFragments();
        for (Text str : text) {
            System.out.println(str);
        }
    }

    //释放资源
    client.close();
}