Example code for using the powerful Elastisearch search engine in Java-javaTutorial-php.cn

This article mainly introduces the use of powerful Elastisearch in Java Search engine example code, which has certain reference value. Those who are interested can learn about it

Elastisearch is a very powerful and easy-to-use engine. SearchIndexEngine

To run Elastisearch on the system, you only need the following steps

1. Download Elastisearch

The code is as follows:

wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-5.4.0.zip

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2. Unzip

unzip elasticsearch-5.4.0.zip

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3. Run

elasticsearch-5.4.0/bin/elasticsearch

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At this time, it may be killed directly. Because of memory overflow (OOM), elastisearch takes up a very large amount of memory. Therefore, when running on a server with relatively small memory, you must first modify the memory size of the jvm

vi elasticsearch-5.4.0/config/jvm.options

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Change the stack size of lines 22 and 23 to 512M

-Xms512M
-Xmx512M

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If it is still killed after restarting, try again Change it to a smaller size

4. Whether the test is successful

curl  &#39;http://localhost:9200/?pretty&#39;

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You can see the following return information:

{
      "status":  200,
      "name":  "Shrunken  Bones",
      "version":  {
            "number":  "1.4.0",
            "lucene_version":  "4.10"
      },
      "tagline":  "You  Know,  for  Search"
}

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It means the startup is successful

Connect Next, we use Java's API to operate Elasticsearch

First, import the elastisearch and log4j packages

POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.jk</groupId>
  <artifactId>ElasticsearchExample</artifactId>
  <version>1.0-SNAPSHOT</version>
  <dependencies>
    <dependency>
      <groupId>org.elasticsearch.client</groupId>
      <artifactId>transport</artifactId>
      <!--用哪个版本就填什么-->
      <version>5.4.0</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.7</version>
    </dependency>
  </dependencies>

</project>

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The following are commonly used Several operations

1. Create client

Client client = null;
    try {
      client = new PreBuiltTransportClient(Settings.EMPTY)
          .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
    } catch (Exception e) {
      e.printStackTrace();
    }

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2. Create index

/**
   * 创建索引，有则先删除
   * @param client
   */
  private static void recreateIndex(Client client) {
    if (client.admin().indices().prepareExists(index).execute().actionGet()
        .isExists()) {
      DeleteIndexResponse deleteIndexResponse = client.admin().indices()
          .delete(new DeleteIndexRequest(index)).actionGet();
      System.out.println("delete index :");
      System.out.println(deleteIndexResponse);
    }

    CreateIndexResponse createIndexResponse = client.admin().indices()
        .prepareCreate(index).execute().actionGet();
    System.out.println("create index :");
    System.out.println(createIndexResponse);
  }

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3.Insert data

/**
   * 插入数据
   * @param client
   */
  @SuppressWarnings({"rawtypes", "unchecked"})
  private static void doIndex(final Client client) {
    Map s11 = new LinkedHashMap();
    s11.put("title", "Think in java");
    s11.put("origin", "美国");
    s11.put("description", "初级java开发人员必读的书");
    s11.put("author", "Bruce Eckel");
    s11.put("price", 108);

    Map s12 = new LinkedHashMap();
    s12.put("title", "Head First Java");
    s12.put("origin", "英国");
    s12.put("description", "java入门教材");
    s12.put("author", "Kathy Sierra");
    s12.put("price", 54);

    Map s21 = new LinkedHashMap();
    s21.put("title", "Design Pattern");
    s21.put("origin", "法国");
    s21.put("description", "程序员不得不读的设计模式");
    s21.put("author", "Kathy Sierra");
    s21.put("price", 89);

    Map s22 = new LinkedHashMap();
    s22.put("title", "黑客与画家");
    s22.put("origin", "法国");
    s22.put("description", "读完之后脑洞大开");
    s22.put("author", "Paul Graham");
    s22.put("price", 35);

    BulkResponse bulkResponse = client
        .prepareBulk()
        .add(client.prepareIndex(index, type).setId("11").setSource(s11).setOpType(IndexRequest.OpType.INDEX).request())
        .add(client.prepareIndex(index, type).setId("12").setSource(s12).setOpType(IndexRequest.OpType.INDEX).request())
        .add(client.prepareIndex(index, type).setId("21").setSource(s21).setOpType(IndexRequest.OpType.INDEX).request())
        .add(client.prepareIndex(index, type).setId("22").setSource(s22).setOpType(IndexRequest.OpType.INDEX).request())
        .execute().actionGet();
    if (bulkResponse.hasFailures()) {
      System.err.println("index docs ERROR:" + bulkResponse.buildFailureMessage());
    } else {
      System.out.println("index docs SUCCESS:");
      System.out.println(bulkResponse);
    }
  }

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4.QueryAll

  /**
   * 查询所有
   */
  private static void searchAll(Client client) {
    SearchResponse response = client.prepareSearch(index)
        .setQuery(QueryBuilders.matchAllQuery())
        .setExplain(true).execute().actionGet();
    System.out.println("searchAll : ");
    for (SearchHit searchHit : response.getHits()) {
      System.out.println("********");
      System.out.println(searchHit.getSource());
    }
  }

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5.Keyword query

  /**
   * 关键词查询
   *
   * @param client
   */
  private static void searchKeyWord(Client client) {
    SearchResponse response = client.prepareSearch(index)
        //查询所有字段匹配关键字
        .setQuery(QueryBuilders.matchQuery("_all", "法国"))
        //设置最小匹配程度
//        .setQuery(QueryBuilders.matchQuery("_all", "法国").minimumShouldMatch("100%"))
        .execute().actionGet();
    System.out.println("searchKeyWord : ");
    System.out.println(response);
  }

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6. Numeric range filtering

  /**
   * 数值范围过滤
   *
   * @param client
   */
  private static void searchRange(Client client) {
    SearchResponse response = client.prepareSearch(index).
        //大于80，小于100
        setQuery(QueryBuilders.rangeQuery("price").gt(80).lt(100))
        .execute()
        .actionGet();
    System.out.println("searchRange : ");
    System.out.println(response);
  }

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7. Sorting

  /**
   * 排序
   *
   * @param client
   */
  private static void searchOrdered(Client client) {
    SearchResponse response = client.prepareSearch(index)
        .setQuery(QueryBuilders.matchAllQuery())
        //根据价格降序排序
        .addSort(SortBuilders.fieldSort("price")
            .order(SortOrder.DESC)).execute().actionGet();
    System.out.println("searchOrdered : ");
    System.out.println(response);
  }

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8.Highlight keywords

/**
   * 高亮关键字
   * @param client
   */
  private static void searchHightlight(Client client) {
    //高亮多个字段
    HighlightBuilder highlightBuilder = new HighlightBuilder();
    highlightBuilder.field("title");
    highlightBuilder.field("description");
    SearchResponse response = client.prepareSearch(index)
        //单条件匹配，高亮时只能高亮该字段
//        .setQuery(QueryBuilders.matchQuery("title", "java"))
        //多条件匹配，高亮时只能高亮多个字段
        .setQuery(QueryBuilders.multiMatchQuery("开发人员必读", "title", "description"))
        .highlighter(highlightBuilder)
        .execute()
        .actionGet();
    System.out.println("searchHightlight : ");
    System.out.println(response);
  }

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9. Search

 /**
   * 根据id查找
   * @param client
   */
  private static void findById(final Client client) {
    String id="12";
    GetResponse response = client.prepareGet(index, type, id).get();
    System.out.println("findById");
    System.out.println(response);
  }

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10. Delete

   /**
   * 删除
   * @param client
   */
  private static void deleteById(Client client) {
    String id="12";
    DeleteResponse response = client.prepareDelete(index, type, id).get();
  }

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11.Update

  /**
   * 更新
   * @param client
   */
  private static void updateById(Client client) {
    try {
      String id="11";
      client.prepareUpdate(index, type, id)
          .setDoc(jsonBuilder()
              .startObject()
              .field("title", "白鹿原")
              .endObject())
          .get();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

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