Example code for using the powerful Elastisearch search engine in Java

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

2. Unzip

unzip elasticsearch-5.4.0.zip

3. Run

elasticsearch-5.4.0/bin/elasticsearch

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

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

-Xms512M
-Xmx512M

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

4. Whether the test is successful

curl  'http://localhost:9200/?pretty'

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"
}

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>

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();
    }

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);
  }

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);
    }
  }

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());
    }
  }

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);
  }

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);
  }

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);
  }

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);
  }

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);
  }

10. Delete

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

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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