问答平台（6），Spring整合Elasticsearch

引入依赖

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

配置 Elasticsearch

# ElasticsearchProperties
spring.data.elasticsearch.cluster-name=nowcoder
spring.data.elasticsearch.cluster-nodes=127.0.0.1:9300（TCP）

解决 netty 启动冲突问题

• CommunityApplication: 修改

  @SpringBootApplication
  public class CommunityApplication {
  
      @PostConstruct
      public void init() {
          // 解决netty启动冲突问题
          // see Netty4Utils.setAvailableProcessors()
          System.setProperty("es.set.netty.runtime.available.processors", "false");
      }
  
      public static void main(String[] args) {
          SpringApplication.run(CommunityApplication.class, args);
      }
  
  }

Spring Data Elasticsearch

- ElasticsearchTemplate
- ElasticsearchRepository

实体类与ES映射（自动）

• entity -> DiscussPost

  @Document(indexName = "discusspost", type = "_doc", shards = 6, replicas = 3)
  public class DiscussPost {
  
      @Id
      private int id;
  
      @Field(type = FieldType.Integer)
      private int userId;
  
      // 互联网校招
      @Field(type = FieldType.Text, analyzer = "ik_max_word", searchAnalyzer = "ik_smart")
      private String title;
  
      @Field(type = FieldType.Text, analyzer = "ik_max_word", searchAnalyzer = "ik_smart")
      private String content;
  
      @Field(type = FieldType.Integer)
      private int type;
  
      @Field(type = FieldType.Integer)
      private int status;
  
      @Field(type = FieldType.Date)
      private Date createTime;
  
      @Field(type = FieldType.Integer)
      private int commentCount;
  
      @Field(type = FieldType.Double)
      private double score;
  }

• dao -> elasticsearch -> DiscussPostRepository

  @Repository
  public interface DiscussPostRepository extends ElasticsearchRepository<DiscussPost, Integer> {
  
  }

测试类

• ElasticsearchTests: 新增

  @RunWith(SpringRunner.class)
  @SpringBootTest
  @ContextConfiguration(classes = CommunityApplication.class)
  public class ElasticsearchTests {
  
      @Autowired
      private DiscussPostMapper discussPostMapper;
  
      @Autowired
      private DiscussPostRepository discussPostRepository;
  
      @Autowired
      private ElasticsearchTemplate elasticsearchTemplate;
  
      @Test
      public void testInsert() {
          discussPostRepository.save(discussPostMapper.selectDiscussPostById(241));
          discussPostRepository.save(discussPostMapper.selectDiscussPostById(242));
          discussPostRepository.save(discussPostMapper.selectDiscussPostById(243));
      }
  
      @Test
      public void testInsertList() {
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(101, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(102, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(103, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(111, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(112, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(131, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(132, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(133, 0, 100));
          discussPostRepository.saveAll(discussPostMapper.selectDiscussPosts(134, 0, 100));
      }
  
      @Test
      public void testUpdate() {
          DiscussPost post = discussPostMapper.selectDiscussPostById(231);
          post.setContent("我是新人,使劲灌水.");
          discussPostRepository.save(post);
      }
  
      @Test
      public void testDelete() {
          // discussPostRepository.deleteById(231);
          discussPostRepository.deleteAll();
      }
  
      @Test
      public void testSearchByRepository() {
          SearchQuery searchQuery = new NativeSearchQueryBuilder()
                  .withQuery(QueryBuilders.multiMatchQuery("互联网寒冬", "title", "content"))
                  .withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC))
                  .withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC))
                  .withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC))
                  .withPageable(PageRequest.of(0, 10))
                  .withHighlightFields(
                          new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),
                          new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")
                  ).build();
  
          // elasticsearchTemplate.queryForPage(searchQuery, class, SearchResultMapper);
          // 底层获取得到了高亮显示的值，但是没有返回.
  
          Page<DiscussPost> page = discussPostRepository.search(searchQuery);
          System.out.println(page.getTotalElements());
          System.out.println(page.getTotalPages());
          System.out.println(page.getNumber());
          System.out.println(page.getSize());
          for (DiscussPost post : page) {
              System.out.println(post);
          }
      }
  
      @Test
      public void testSearchByTemplate() {
          SearchQuery searchQuery = new NativeSearchQueryBuilder()
                  .withQuery(QueryBuilders.multiMatchQuery("互联网寒冬", "title", "content"))
                  .withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC))
                  .withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC))
                  .withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC))
                  .withPageable(PageRequest.of(0, 10))
                  .withHighlightFields(
                          new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),
                          new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")
                  ).build();
  
          Page<DiscussPost> page = elasticsearchTemplate.queryForPage(searchQuery, DiscussPost.class, new SearchResultMapper() {
              @Override
              public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> aClass, Pageable pageable) {
                  SearchHits hits = response.getHits();
                  if (hits.getTotalHits() <= 0) {
                      return null;
                  }
  
                  List<DiscussPost> list = new ArrayList<>();
                  for (SearchHit hit : hits) {
                      DiscussPost post = new DiscussPost();
  
                      String id = hit.getSourceAsMap().get("id").toString();
                      post.setId(Integer.valueOf(id));
  
                      String userId = hit.getSourceAsMap().get("userId").toString();
                      post.setUserId(Integer.valueOf(userId));
  
                      String title = hit.getSourceAsMap().get("title").toString();
                      post.setTitle(title);
  
                      String content = hit.getSourceAsMap().get("content").toString();
                      post.setContent(content);
  
                      String status = hit.getSourceAsMap().get("status").toString();
                      post.setStatus(Integer.valueOf(status));
  
                      String createTime = hit.getSourceAsMap().get("createTime").toString();
                      post.setCreateTime(new Date(Long.valueOf(createTime)));
  
                      String commentCount = hit.getSourceAsMap().get("commentCount").toString();
                      post.setCommentCount(Integer.valueOf(commentCount));
  
                      // 处理高亮显示的结果
                      HighlightField titleField = hit.getHighlightFields().get("title");
                      if (titleField != null) {
                          post.setTitle(titleField.getFragments()[0].toString());
                      }
  
                      HighlightField contentField = hit.getHighlightFields().get("content");
                      if (contentField != null) {
                          post.setContent(contentField.getFragments()[0].toString());
                      }
  
                      list.add(post);
                  }
  
                  return new AggregatedPageImpl(list, pageable,
                          hits.getTotalHits() , response.getAggregations(), response.getScrollId(), hits.getMaxScore());
              }
          });
  
          System.out.println(page.getTotalElements());
          System.out.println(page.getTotalPages());
          System.out.println(page.getNumber());
          System.out.println(page.getSize());
          for (DiscussPost post : page) {
              System.out.println(post);
          }
      }
  }

结果展示