Java日记——使用强大的Elastisearch搜索引擎

Elastisearch是一个很强大,易用的搜索引擎
在系统上运行Elastisearch只需以下几步

1.下载Elastisearch

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

2.解压

unzip elasticsearch-5.4.0.zip

3.运行

elasticsearch-5.4.0/bin/elasticsearch

这时有可能会直接被Killed掉，因为内存溢出（OOM），elastisearch占用的内存非常大，所以在内存比较小的服务器上运行要先修改jvm的内存大小

vi elasticsearch-5.4.0/config/jvm.options

将22和23行的栈堆大小改为512M

-Xms512M-Xmx512M

如果重新启动后还是killed就再改小一点

4.测试是否成功

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

你能看到以下返回信息:

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

则表明启动成功

接下来我们用Java的API来操作Elasticsearch

首先是导入elastisearch和log4j的包

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>

以下是常用的几种操作

1.创建client

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

2.创建索引

/**     * 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.插入数据

/**     * 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.查询所有

    /**     * 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.关键词查询

    /**     * 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.数值范围过滤

    /**     * 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.排序

    /**     * 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.高亮关键字

/**     * 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.根据id查找

    /**     * 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.删除

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

11.更新

    /**     * 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();        }    }

常用的操作就这些,代码上传到https://github.com/jkgeekJack/ElasticsearchExample

建议大家还可以看看Elasticsearch: 权威指南,这里有更详细的介绍