Springboot整合Elasticsearch(查询数据的方式)

参考文档地址:
Elasticsearch 官方文档地址:点击链接
Spring Data Elasticsearch 官方文档地址:点击链接

添加maven依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</dependency>

1.初始化Elasticsearch

• 在yml配置文件中配置es的连接参数(略)
• 新建一个config类，配置es(如下)

@Configuration
public class ElasticsearchConfig {

    @Bean
    public RestHighLevelClient restHighLevelClient() {
        // 这个是springboot的文档推荐写法
//        ClientConfiguration clientConfiguration = ClientConfiguration.builder()
//                .connectedTo("192.168.203.129:9200").build();
//
//        return RestClients.create(clientConfiguration).rest();

        // es官方文档推荐写法
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("192.168.203.129", 9200, "http")));
        return client;
    }
}

2.简单查询

Spring Data Elasticsearch提供了一个ElasticsearchRepository接口，可以很方便的自定义简单的查询方法。

public interface MyRepository extends ElasticsearchRepository<User, Long> {

    /**
     * 根据id或者年龄或者名字查询
     * @param id
     * @param age
     * @param name
     * @return
     */
    User findByIdOrAgeOrName(Long id, Integer age, String name);

    /**
     * 删除年龄大于或等于给定值的数据
     * @param age
     */
    void deleteByAgeGreaterThanEqual(Integer age);

    /**
     * 搜索指定年龄段的user
     * @param start 开始年龄
     * @param end 结束年龄
     * @return
     */
    User findAllByAgeBetween(int start,int end);


}

这里要注意，自定义方法的名字是有规则的，idea会自动提示，根据提示，以及自己想要的操作，书写方法名和对应参数即可。在Spring Data Elasticsearch的文档里也有相关说明：

 

1.1测试代码

@Autowired  
private MyRepository myRepository;

// 查询年龄为27岁的用户数据
@Test
void myTest6() {
    User rico = myRepository.findByIdOrAgeOrName(null, 27, null);
    System.out.println(rico);
}

// 插入一条user数据
@Test
void myTest7() throws IOException {
    User user = User.builder()
            .name("rico3")
            .age(35)
            .id(3L)
            .birthday(new Date())
            .build();

    User save = myRepository.save(user);
    System.out.println(save);
    restHighLevelClient.close();
}

// 删除年龄大于或等于29岁的用户的数据
@Test
void myTest8() throws IOException {
    myRepository.deleteByAgeGreaterThanEqual(29);
    restHighLevelClient.close();
}

3.复杂查询

　　3.1使用ElasticsearchRestTemplate

先看测试代码

@Autowired
private ElasticsearchRestTemplate elasticsearchRestTemplate;

// 使用elasticsearchRestTemplate来查询数据
@Test
void myTest9() {
    // 创建一个query，QueryBuilders下可以选择查询方式
    NativeSearchQuery nativeSearchQuery = new NativeSearchQuery(QueryBuilders.matchAllQuery());
    SearchHits<User> search = elasticsearchRestTemplate.search(nativeSearchQuery, User.class);
    for (org.springframework.data.elasticsearch.core.SearchHit<User> userSearchHit : search) {
        User content = userSearchHit.getContent();
        System.out.println(content);
    }
}

@Test
void myTest11() {
    NativeSearchQueryBuilder builder = new NativeSearchQueryBuilder();
    builder.withQuery(QueryBuilders.matchAllQuery());
    // 搜索age大于27的user数据,这里的写法其实和json查询语句的写法一样的，如下
    /*
    GET /bank/_search
    {
      "query": {
        "bool": {
          "must": { "match_all": {} },
          "filter": {
            "range": {
              "balance": {
                "gte": 20000,
                "lte": 30000
              }
            }
          }
        }
      }
    }
     */
    builder.withQuery(QueryBuilders.boolQuery()
            .must(QueryBuilders.matchAllQuery())
            .filter(QueryBuilders.rangeQuery("age").gte(27)));
    NativeSearchQuery query = builder.build();
    SearchHits<User> searchHits = elasticsearchRestTemplate.search(query, User.class);
    for (org.springframework.data.elasticsearch.core.SearchHit<User> searchHit : searchHits) {
        System.out.println(searchHit.getContent());
    }
}

// 查询年龄大于10岁的用户的数量
@Test
public void myTest14() {
    NativeSearchQueryBuilder builder = new NativeSearchQueryBuilder();
    builder.addAggregation(AggregationBuilders
            .filter("age_gt_10", QueryBuilders.rangeQuery("age").gt(10))
            .subAggregation(AggregationBuilders.count("group_by_count").field("name")));
    NativeSearchQuery searchQuery = builder.build();
    SearchHits<User> search = elasticsearchRestTemplate.search(searchQuery, User.class);
    Filter age_gt_10 = search.getAggregations().get("age_gt_10");
    Aggregations aggregations = age_gt_10.getAggregations();
    ValueCount count = aggregations.get("group_by_count");
    System.out.println(count.getValue());
}

ElasticsearchRestTemplate适合做一些复杂的搜索操作，比如聚合搜索等。需要注意的是，ElasticsearchRestTemplate查询返回的结果需要传入我们的数据实体类User.class。

@Data
@Document(indexName = "users") // 将此类标记为Document，索引是users，对应es里的数据
@Builder
public class User {
    @Id
    private Long id;
    @Field(type = FieldType.Keyword)
    private String name;
    @Field(type = FieldType.Long)
    private Integer age;
    @Field(type = FieldType.Date,format= DateFormat.basic_date)
    private Date birthday;
}

还有一个需要注意：在上面的代码myTest14函数中，builder的写法需要基本是和es的json查询语句一样的，如下：

 输出结果是：

3.2使用RestHighLevelClient

@Autowired  
private RestHighLevelClient restHighLevelClient;

@Test
void myTest() throws IOException {
    // 创建一个索引，并设置了id为1的文档数据
    IndexRequest request = new IndexRequest("spring-data3")
            .id("1")
            .opType(DocWriteRequest.OpType.CREATE)
            .source("name", "rico2")
            .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
    IndexResponse response = restHighLevelClient.index(request, RequestOptions.DEFAULT);
    System.out.println(response.toString());
    restHighLevelClient.close();

// 获取文档内容
@Test
void myTest4() throws IOException {
    GetRequest getRequest = new GetRequest("users", "1");
    boolean exists = restHighLevelClient.indices().exists(new GetIndexRequest(getRequest.index()), RequestOptions.DEFAULT);
    if (exists) {
        GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
        System.out.println(getResponse.getSourceAsString());
    } else {
        System.out.println("索引不存在!");
    }
    restHighLevelClient.close();
}

// 搜索index为users下的所有文档
@Test
void myTest5() throws IOException {
    SearchRequest searchRequest = new SearchRequest("users");
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    searchSourceBuilder.query(QueryBuilders.matchAllQuery());
    searchRequest.source(searchSourceBuilder);
    SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
    SearchHit[] hits = search.getHits().getHits();
    for (SearchHit hit : hits) {
        System.out.println(hit.getSourceAsString());
        System.out.println("=================================");
    }

}

// 查询users下所有用户的年龄平均值
@Test
public void myTest12() throws IOException {
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    AvgAggregationBuilder avgAggregationBuilder = AggregationBuilders.avg("average_age").field("age");
    searchSourceBuilder.aggregation(avgAggregationBuilder);

    SearchRequest request = new SearchRequest("users");
    request.source(searchSourceBuilder);

    SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
    Aggregations aggregations = response.getAggregations();
    Avg average_age = aggregations.get("average_age");
    System.out.println(average_age.getValue());
}

// 查询年龄大于10岁的用户的数量，使用restHighLevelClient
@Test
public void myTest13() throws IOException {
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    FilterAggregationBuilder filter = AggregationBuilders
            .filter("age_gt_10", QueryBuilders.rangeQuery("age").gt(10));
    filter.subAggregation(AggregationBuilders.count("group_by_count").field("name"));
    searchSourceBuilder.aggregation(filter);

    SearchRequest request = new SearchRequest("users");
    request.source(searchSourceBuilder);

    SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
    Aggregations aggregations = response.getAggregations();
    Filter age_gt_10 = aggregations.get("age_gt_10");
    Aggregations aggregations1 = age_gt_10.getAggregations();
    ValueCount group_by_count = aggregations1.get("group_by_count");
    System.out.println(group_by_count.getValue());
}

可以看出，RestHighLevelClient既可以做简单的查询，也可以做复杂的查询。如果只需要做简单的数据操作，还是建议用ElasticsearchRepository，代码更简单。和ElasticsearchRestTemplate一样，建立查询条件的代码要参照es的json查询语句的写法，比如这里的myTest13用的就是嵌套查询。