Java API 操作ES

POM依賴

 <repositories><!-- 代碼庫 -->
        <repository>
            <id>aliyun</id>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
                <updatePolicy>never</updatePolicy>
            </snapshots>
        </repository>

        <repository>
            <id>elastic.co</id>
            <url>https://artifacts.elastic.co/maven</url>
        </repository>
    </repositories>

    <dependencies>
        <!-- ES的高階的客戶端API -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.6.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.11.1</version>
        </dependency>
        <!-- 阿里巴巴出品的一款將Java物件轉換為JSON、將JSON轉換為Java物件的庫 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.62</version>
        </dependency>
        <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>6.14.3</version>
            <scope>test</scope>
        </dependency>
        <!-- ES SQL驅動 -->
        <dependency>
            <groupId>org.elasticsearch.plugin</groupId>
            <artifactId>x-pack-sql-jdbc</artifactId>
            <version>7.6.1</version>
        </dependency>
    </dependencies>

創建Bean

public class JobDetail {

    @JSONField(serialize = false)
    private long id;
    private String area;
    private String exp;
    private String edu;
    private String salary;
    private String job_type;
    private String cmp;
    private String pv;
    private String title;
    private String jd;
    private int age;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getArea() {
        return area;
    }

    public void setArea(String area) {
        this.area = area;
    }

    public String getExp() {
        return exp;
    }

    public void setExp(String exp) {
        this.exp = exp;
    }

    public String getEdu() {
        return edu;
    }

    public void setEdu(String edu) {
        this.edu = edu;
    }

    public String getSalary() {
        return salary;
    }

    public void setSalary(String salary) {
        this.salary = salary;
    }

    public String getJob_type() {
        return job_type;
    }

    public void setJob_type(String job_type) {
        this.job_type = job_type;
    }

    public String getCmp() {
        return cmp;
    }

    public void setCmp(String cmp) {
        this.cmp = cmp;
    }

    public String getPv() {
        return pv;
    }

    public void setPv(String pv) {
        this.pv = pv;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getJd() {
        return jd;
    }

    public void setJd(String jd) {
        this.jd = jd;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        // 使用FastJSON將一個物件直接轉換為JSON字串
        return id + ":" + JSONObject.toJSONString(this);
    }
}

定義操作資料介面

public interface JobFullTextService {
    // 添加一個職位資料
    void add(JobDetail jobDetail) throws IOException;

    // 根據ID檢索指定職位資料
    JobDetail findById(long id) throws IOException;

    // 修改職位薪資
    void update(JobDetail jobDetail) throws IOException;

    // 根據ID洗掉指定位置資料
    void deleteById(long id) throws IOException;

    // 根據關鍵字檢索資料
    List<JobDetail> searchByKeywords(String keywords) throws IOException;

    // 分頁檢索
    Map<String, Object> searchByPage(String keywords, int pageNum, int pageSize) throws IOException;

    // scroll分頁解決深分頁問題
    Map<String, Object> searchByScrollPage(String keywords, String scrollId, int pageSize) throws IOException;


    // 關閉ES連接
    void close() throws IOException;
}

介面實作類API

public class JobFullTextServiceImpl implements JobFullTextService {

    private RestHighLevelClient restHighLevelClient;
    // 索引庫的名字
    private static final String JOB_IDX = "job_index";

    public JobFullTextServiceImpl() {
        // 建立與ES的連接
        // 1. 使用RestHighLevelClient構建客戶端連接，
        // 2. 基于RestClient.builder方法來構建RestClientBuilder
        // 3. 用HttpHost來添加ES的節點
        RestClientBuilder restClientBuilder = RestClient.builder(
                new HttpHost("192.168.21.130", 9200, "http")
                , new HttpHost("192.168.21.131", 9200, "http")
                , new HttpHost("192.168.21.132", 9200, "http"));
       /* RestClientBuilder restClientBuilder = RestClient.builder(
                new HttpHost("192.168.21.130", 9200, "http"));*/
        restHighLevelClient = new RestHighLevelClient(restClientBuilder);
    }

    @Override
    public void add(JobDetail jobDetail) throws IOException {
        //1.	構建IndexRequest物件，用來描述ES發起請求的資料，
        IndexRequest indexRequest = new IndexRequest(JOB_IDX);

        //2.	設定檔案ID，
        indexRequest.id(jobDetail.getId() + "");

        //3.	使用FastJSON將物體類物件轉換為JSON，
        String json = JSONObject.toJSONString(jobDetail);

        //4.	使用IndexRequest.source方法設定檔案資料，并設定請求的資料為JSON格式，
        indexRequest.source(json, XContentType.JSON);

        //5.	使用ES High level client呼叫index方法發起請求，將一個檔案添加到索引中，
        restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);
    }

    @Override
    public JobDetail findById(long id) throws IOException {
        // 1.	構建GetRequest請求，
        GetRequest getRequest = new GetRequest(JOB_IDX, id + "");

        // 2.	使用RestHighLevelClient.get發送GetRequest請求，并獲取到ES服務器的回應，
        GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);

        // 3.	將ES回應的資料轉換為JSON字串
        String json = getResponse.getSourceAsString();

        // 4.	并使用FastJSON將JSON字串轉換為JobDetail類物件
        JobDetail jobDetail = JSONObject.parseObject(json, JobDetail.class);

        // 5.	記得：單獨設定ID
        jobDetail.setId(id);

        return jobDetail;
    }

    @Override
    public void update(JobDetail jobDetail) throws IOException {
        // 1.	判斷對應ID的檔案是否存在
        // a)	構建GetRequest
        GetRequest getRequest = new GetRequest(JOB_IDX, jobDetail.getId() + "");

        // b)	執行client的exists方法，發起請求，判斷是否存在
        boolean exists = restHighLevelClient.exists(getRequest, RequestOptions.DEFAULT);

        if(exists) {
            // 2.	構建UpdateRequest請求
            UpdateRequest updateRequest = new UpdateRequest(JOB_IDX, jobDetail.getId() + "");

            // 3.	設定UpdateRequest的檔案，并配置為JSON格式
            updateRequest.doc(JSONObject.toJSONString(jobDetail), XContentType.JSON);

            // 4.	執行client發起update請求
            restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);
        }
    }

    @Override
    public void deleteById(long id) throws IOException {
        // 1.	構建delete請求
        DeleteRequest deleteRequest = new DeleteRequest(JOB_IDX, id + "");

        // 2.	使用RestHighLevelClient執行delete請求
        restHighLevelClient.delete(deleteRequest, RequestOptions.DEFAULT);

    }

    @Override
    public List<JobDetail> searchByKeywords(String keywords) throws IOException {
        // 1.構建SearchRequest檢索請求
        // 專門用來進行全文檢索、關鍵字檢索的API
        SearchRequest searchRequest = new SearchRequest(JOB_IDX);

        // 2.創建一個SearchSourceBuilder專門用于構建查詢條件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

        // 3.使用QueryBuilders.multiMatchQuery構建一個查詢條件（搜索title、jd），并配置到SearchSourceBuilder
        MultiMatchQueryBuilder multiMatchQueryBuilder = QueryBuilders.multiMatchQuery(keywords, "title", "jd");

        // 將查詢條件設定到查詢請求構建器中
        searchSourceBuilder.query(multiMatchQueryBuilder);

        // 4.呼叫SearchRequest.source將查詢條件設定到檢索請求
        searchRequest.source(searchSourceBuilder);

        // 5.執行RestHighLevelClient.search發起請求
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHit[] hitArray = searchResponse.getHits().getHits();

        // 6.遍歷結果
        ArrayList<JobDetail> jobDetailArrayList = new ArrayList<>();

        for (SearchHit documentFields : hitArray) {
            // 1)獲取命中的結果
            String json = documentFields.getSourceAsString();

            // 2)將JSON字串轉換為物件
            JobDetail jobDetail = JSONObject.parseObject(json, JobDetail.class);

            // 3)使用SearchHit.getId設定檔案ID
            jobDetail.setId(Long.parseLong(documentFields.getId()));

            jobDetailArrayList.add(jobDetail);
        }

        return jobDetailArrayList;
    }

    @Override
    public Map<String, Object> searchByPage(String keywords, int pageNum, int pageSize) throws IOException {
        // 1.構建SearchRequest檢索請求
        // 專門用來進行全文檢索、關鍵字檢索的API
        SearchRequest searchRequest = new SearchRequest(JOB_IDX);

        // 2.創建一個SearchSourceBuilder專門用于構建查詢條件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

        // 3.使用QueryBuilders.multiMatchQuery構建一個查詢條件（搜索title、jd），并配置到SearchSourceBuilder
        MultiMatchQueryBuilder multiMatchQueryBuilder = QueryBuilders.multiMatchQuery(keywords, "title", "jd");

        // 將查詢條件設定到查詢請求構建器中
        searchSourceBuilder.query(multiMatchQueryBuilder);

        // 每頁顯示多少條
        searchSourceBuilder.size(pageSize);
        // 設定從第幾條開始查詢
        searchSourceBuilder.from((pageNum - 1) * pageSize);

        // 4.呼叫SearchRequest.source將查詢條件設定到檢索請求
        searchRequest.source(searchSourceBuilder);

        // 5.執行RestHighLevelClient.search發起請求
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHit[] hitArray = searchResponse.getHits().getHits();

        // 6.遍歷結果
        ArrayList<JobDetail> jobDetailArrayList = new ArrayList<>();

        for (SearchHit documentFields : hitArray) {
            // 1)獲取命中的結果
            String json = documentFields.getSourceAsString();

            // 2)將JSON字串轉換為物件
            JobDetail jobDetail = JSONObject.parseObject(json, JobDetail.class);

            // 3)使用SearchHit.getId設定檔案ID
            jobDetail.setId(Long.parseLong(documentFields.getId()));

            jobDetailArrayList.add(jobDetail);
        }

        // 8.	將結果封裝到Map結構中（帶有分頁資訊）
        // a)	total -> 使用SearchHits.getTotalHits().value獲取到所有的記錄數
        // b)	content -> 當前分頁中的資料
        long totalNum = searchResponse.getHits().getTotalHits().value;
        HashMap hashMap = new HashMap();
        hashMap.put("total", totalNum);
        hashMap.put("content", jobDetailArrayList);


        return hashMap;
    }

    @Override
    public Map<String, Object> searchByScrollPage(String keywords, String scrollId, int pageSize) throws IOException {
        SearchResponse searchResponse = null;

        if(scrollId == null) {
            // 1.構建SearchRequest檢索請求
            // 專門用來進行全文檢索、關鍵字檢索的API
            SearchRequest searchRequest = new SearchRequest(JOB_IDX);

            // 2.創建一個SearchSourceBuilder專門用于構建查詢條件
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

            // 3.使用QueryBuilders.multiMatchQuery構建一個查詢條件（搜索title、jd），并配置到SearchSourceBuilder
            MultiMatchQueryBuilder multiMatchQueryBuilder = QueryBuilders.multiMatchQuery(keywords, "title", "jd");

            // 將查詢條件設定到查詢請求構建器中
            searchSourceBuilder.query(multiMatchQueryBuilder);

            // 設定高亮
            HighlightBuilder highlightBuilder = new HighlightBuilder();
            highlightBuilder.field("title");
            highlightBuilder.field("jd");
            highlightBuilder.preTags("<font color='red'>");
            highlightBuilder.postTags("</font>");

            // 給請求設定高亮
            searchSourceBuilder.highlighter(highlightBuilder);

            // 每頁顯示多少條
            searchSourceBuilder.size(pageSize);

            // 4.呼叫SearchRequest.source將查詢條件設定到檢索請求
            searchRequest.source(searchSourceBuilder);

            //--------------------------
            // 設定scroll查詢
            //--------------------------
            searchRequest.scroll(TimeValue.timeValueMinutes(5));

            // 5.執行RestHighLevelClient.search發起請求
            searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        }
        // 第二次查詢的時候，直接通過scroll id查詢資料
        else {
            SearchScrollRequest searchScrollRequest = new SearchScrollRequest(scrollId);
            searchScrollRequest.scroll(TimeValue.timeValueMinutes(5));

            // 使用RestHighLevelClient發送scroll請求
            searchResponse = restHighLevelClient.scroll(searchScrollRequest, RequestOptions.DEFAULT);
        }

        //--------------------------
        // 迭代ES回應的資料
        //--------------------------

        SearchHit[] hitArray = searchResponse.getHits().getHits();

        // 6.遍歷結果
        ArrayList<JobDetail> jobDetailArrayList = new ArrayList<>();

        for (SearchHit documentFields : hitArray) {
            // 1)獲取命中的結果
            String json = documentFields.getSourceAsString();

            // 2)將JSON字串轉換為物件
            JobDetail jobDetail = JSONObject.parseObject(json, JobDetail.class);

            // 3)使用SearchHit.getId設定檔案ID
            jobDetail.setId(Long.parseLong(documentFields.getId()));

            jobDetailArrayList.add(jobDetail);

            // 設定高亮的一些文本到物體類中
            // 封裝了高亮
            Map<String, HighlightField> highlightFieldMap = documentFields.getHighlightFields();
            HighlightField titleHL = highlightFieldMap.get("title");
            HighlightField jdHL = highlightFieldMap.get("jd");

            if(titleHL != null) {
                // 獲取指定欄位的高亮片段
                Text[] fragments = titleHL.getFragments();
                // 將這些高亮片段拼接成一個完整的高亮欄位
                StringBuilder builder = new StringBuilder();
                for(Text text : fragments) {
                    builder.append(text);
                }
                // 設定到物體類中
                jobDetail.setTitle(builder.toString());
            }

            if(jdHL != null) {
                // 獲取指定欄位的高亮片段
                Text[] fragments = jdHL.getFragments();
                // 將這些高亮片段拼接成一個完整的高亮欄位
                StringBuilder builder = new StringBuilder();
                for(Text text : fragments) {
                    builder.append(text);
                }
                // 設定到物體類中
                jobDetail.setJd(builder.toString());
            }
        }

        // 8.	將結果封裝到Map結構中（帶有分頁資訊）
        // a)	total -> 使用SearchHits.getTotalHits().value獲取到所有的記錄數
        // b)	content -> 當前分頁中的資料
        long totalNum = searchResponse.getHits().getTotalHits().value;
        HashMap hashMap = new HashMap();
        hashMap.put("scroll_id", searchResponse.getScrollId());
        hashMap.put("content", jobDetailArrayList);

        return hashMap;
    }



    @Override
    public void close() throws IOException {
        restHighLevelClient.close();
    }
}