📢 本文由 gemini-2.5-flash 翻譯
Elasticsearch 系列
文件的查詢相同地使用 RestHighLevelClient 物件
match_all
發出請求如下：
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| @Test
public void testMatchAll() throws IOException {
// 準備request
SearchRequest request = new SearchRequest("hotel");
// 組織DSL參數
request.source().query(QueryBuilders.matchAllQuery());
// 傳送請求
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
System.out.println(response);
}
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解析回應
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| @Test
public void testMatchAll() throws IOException {
// 準備request
SearchRequest request = new SearchRequest("hotel");
// 組織DSL參數
request.source().query(QueryBuilders.matchAllQuery());
// 傳送請求
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
// 解析結果
SearchHits searchHits = response.getHits();
// 查詢的總筆數
long total = searchHits.getTotalHits().value;
// 查詢結果陣列
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
System.out.println(json);
}
}
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es 回傳的結果是一個 JSON 字串，包含：
- hits：命中結果
- total：總筆數，其中 value 是具體的總筆數值
- max_score：所有結果中得分最高的文件的相關性分數
- hits：搜尋結果的文件陣列，其中的每個文件都是一個 JSON 物件
- source：文件中的原始資料，也是 JSON 物件
因此，解析回應結果，就是逐層解析 JSON 字串，流程如下：
SearchHits：透過 response.getHits() 取得，就是 JSON 中的最外層 hits，代表命中的結果SearchHits.getTotalHits().value：取得總筆數資訊SearchHits.getHits()：取得 SearchHit 陣列，也就是文件陣列SearchHit.getSourceAsString()：取得文件結果中的 _source，也就是原始的 JSON 文件資料
match 與 multi_match
與 match_all 類似，差別在於查詢條件
match 程式碼
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| @Test
public void testMatch() throws IOException {
SearchRequest request = new SearchRequest("hotel");
request.source().query(QueryBuilders.matchQuery("all", "如家"));
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
SearchHits searchHits = response.getHits();
long total = searchHits.getTotalHits().value;
System.out.println(total);
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
System.out.println(json);
}
}
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multi_match 程式碼
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| @Test
public void testMultiMatch() throws IOException {
SearchRequest request = new SearchRequest("hotel");
request.source().query(QueryBuilders.multiMatchQuery("如家", "brand", "name"));
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
SearchHits searchHits = response.getHits();
long total = searchHits.getTotalHits().value;
System.out.println(total);
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
System.out.println(json);
}
}
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可以看到程式碼重複部分較多，使用 Ctrl+Alt+M 進行程式碼提取，term 程式碼展現了提取
精準查詢
term 詞條精確比對查詢
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| @Test
public void testTerm() throws IOException {
SearchRequest request = new SearchRequest("hotel");
request.source().query(QueryBuilders.termQuery("city", "上海"));
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
responseHandle(response);
}
// 回應處理程式碼提取
private static void responseHandle(SearchResponse response) {
SearchHits searchHits = response.getHits();
long total = searchHits.getTotalHits().value;
System.out.println(total);
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
System.out.println(json);
}
}
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range 範圍查詢
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| @Test
public void testRange() throws IOException {
SearchRequest request = new SearchRequest("hotel");
request.source().query(QueryBuilders
.rangeQuery("price")
.gte(100)
.lte(400));
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
responseHandle(response);
}
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布林查詢
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| @Test
public void testBool() throws IOException {
SearchRequest request = new SearchRequest("hotel");
// 建構布林查詢
BoolQueryBuilder booledQuery = QueryBuilders.boolQuery();
// 加入must條件
booledQuery.must(QueryBuilders.termQuery("city", "上海"));
// 加入filter元件
booledQuery.filter(QueryBuilders.rangeQuery("price").lte(300));
request.source().query(booledQuery);
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
responseHandle(response);
}
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排序與分頁
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| @Test
public void testSort() throws IOException {
SearchRequest request = new SearchRequest("hotel");
request.source().query(QueryBuilders.matchAllQuery());
request.source().from(10).size(10);
request.source().sort("price", SortOrder.ASC);
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
responseHandle(response);
}
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高亮
高亮與上述程式碼差異較大，請求建構
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| @Test
public void testHigh() throws IOException {
SearchRequest request = new SearchRequest("hotel");
// DSL
request.source().query(QueryBuilders.matchQuery("all", "漢庭"));
// 高亮
request.source().highlighter(
new HighlightBuilder()
.field("name")
.requireFieldMatch(false)
);
// 傳送請求
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
// 解析
responseHandle(response);
}
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因為查詢文件結果與高亮分離，結果解析需要額外處理
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| @Test
public void testHigh() throws IOException {
SearchRequest request = new SearchRequest("hotel");
// DSL
request.source().query(QueryBuilders.matchQuery("all", "漢庭"));
// 高亮
request.source().highlighter(
new HighlightBuilder()
.field("name")
.requireFieldMatch(false)
);
// 傳送請求
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
// 解析
SearchHits searchHits = response.getHits();
// 總筆數
long total = searchHits.getTotalHits().value;
System.out.println(total);
// 文件陣列
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
// 反序列化
HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
// 取得高亮結果
Map<String, HighlightField> highlightFields = hit.getHighlightFields();
if(!CollectionUtils.isEmpty(highlightFields)){
// 取得高亮結果
HighlightField highlightField = highlightFields.get("name");
if (highlightField != null){
String name = highlightField.getFragments()[0].toString();
// 覆寫非高亮
hotelDoc.setName(name);
}
}
System.out.println(hotelDoc);
}
}
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飯店查詢案例
實現四部分功能：
- 飯店搜尋與分頁
- 飯店結果篩選
- 我周邊的飯店
- 飯店競價排名
搜尋與分頁
搜尋請求：
- 請求方式：POST
- 請求路徑：/hotel/list
- 請求參數：JSON 物件，包含 4 個欄位：
- key：搜尋關鍵字
- page：頁碼
- size：每頁大小
- sortBy：排序，目前暫不實作
- 回傳值：分頁查詢，需要回傳分頁結果 PageResult，包含兩個屬性：
total：總筆數List<HotelDoc>：當前頁的資料
首先定義實體類別，接收參數
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| @Data
public class RequestParams {
private String key;
private Integer page;
private Integer size;
private String sortBy;
}
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定義回傳類別
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| @Data
public class PageResult {
private Long total;
private List<HotelDoc> hotels;
public PageResult(){
}
public PageResult(Long total, List<HotelDoc> hotels) {
this.total = total;
this.hotels = hotels;
}
}
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定義 Controller
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| @RestController
@RequestMapping("/hotel")
public class HotelController {
@Autowired
private IHotelService hotelService;
@PostMapping("/list")
public PageResult search(@RequestBody RequestParams params){
return hotelService.search(params);
}
}
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實作搜尋業務，首先註冊一個 Bean 物件
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| @Bean
public RestHighLevelClient client(){
return new RestHighLevelClient(RestClient
.builder(HttpHost.create("http://ip:9200")
));
}
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撰寫邏輯
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| public PageResult search(RequestParams params) {
// request
SearchRequest request = new SearchRequest("hotel");
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
// DSL
String key = params.getKey();
if (key == null || "".equals(key)){
boolQuery.must(QueryBuilders.matchAllQuery());
}else {
boolQuery.must(QueryBuilders.matchQuery("all", key));
}
// 分頁
int page = params.getPage();
int size = params.getSize();
request.source().from((page - 1) * size).size(size);
// 查詢
request.source().query(boolQuery);
// 傳送請求
try {
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
// 回應解析
SearchHits searchHits = response.getHits();
// 總數
long total = searchHits.getTotalHits().value;
// 文件
SearchHit[] hits = searchHits.getHits();
// 遍歷
List<HotelDoc> hotels = new ArrayList<>();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
hotels.add(hotelDoc);
}
return new PageResult(total, hotels);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
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結果篩選
包含的篩選條件：
- brand：品牌值
- city：城市
- minPrice~maxPrice：價格範圍
- starName：星級
修改實體類別
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| @Data
public class RequestParams {
private String key;
private Integer page;
private Integer size;
private String sortBy;
// 下面是新增的篩選條件參數
private String city;
private String brand;
private String starName;
private Integer minPrice;
private Integer maxPrice;
}
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修改查詢條件
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| @Override
public PageResult search(RequestParams params) {
// request
SearchRequest request = new SearchRequest("hotel");
basicQuery(params, request);
// 分頁
int page = params.getPage();
int size = params.getSize();
request.source().from((page - 1) * size).size(size);
// 傳送請求
try {
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
// 回應解析
SearchHits searchHits = response.getHits();
// 總數
long total = searchHits.getTotalHits().value;
// 文件
SearchHit[] hits = searchHits.getHits();
// 遍歷
List<HotelDoc> hotels = new ArrayList<>();
for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
hotels.add(hotelDoc);
}
return new PageResult(total, hotels);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private static void basicQuery(RequestParams params, SearchRequest request) {
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
// 輸入內容
String key = params.getKey();
if (key == null || "".equals(key)){
boolQuery.must(QueryBuilders.matchAllQuery());
}else {
boolQuery.must(QueryBuilders.matchQuery("all", key));
}
// brand
if (params.getBrand() != null && !params.getBrand().equals("")){
boolQuery.filter(QueryBuilders.termQuery("brand", params.getBrand()));
}
// starName
if (params.getStarName() != null && !params.getStarName().equals("")){
boolQuery.filter(QueryBuilders.termQuery("starName", params.getStarName()));
}
// city
if (params.getCity() != null && !params.getStarName().equals("")){
boolQuery.filter(QueryBuilders.termQuery("city", params.getCity()));
}
// price
if (params.getMinPrice() != null && params.getMaxPrice() != null){
boolQuery.filter(QueryBuilders.rangeQuery("price").gte(params.getMinPrice()).lte(params.getMaxPrice()));
}
// 查詢
request.source().query(boolQuery);
}
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附近的飯店
基於 location 座標，依距離對周圍的飯店排序
修改實體類別
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| @Data
public class RequestParams {
private String key;
private Integer page;
private Integer size;
private String sortBy;
private String city;
private String brand;
private String starName;
private Integer minPrice;
private Integer maxPrice;
// 我目前的地理座標
private String location;
}
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加入距離排序
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| if (params.getLocation() != null) {
// 距離排序
request.source().sort(SortBuilders
.geoDistanceSort("location", new GeoPoint(params.getLocation()))
.order(SortOrder.ASC)
.unit(DistanceUnit.KILOMETERS)
);
}
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距離顯示
修改 HotelDoc，加入距離
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| @Data
@NoArgsConstructor
public class HotelDoc {
private Long id;
private String name;
private String address;
private Integer price;
private Integer score;
private String brand;
private String city;
private String starName;
private String business;
private String location;
private String pic;
// 距離
private Object distance;
public HotelDoc(Hotel hotel) {
this.id = hotel.getId();
this.name = hotel.getName();
this.address = hotel.getAddress();
this.price = hotel.getPrice();
this.score = hotel.getScore();
this.brand = hotel.getBrand();
this.city = hotel.getCity();
this.starName = hotel.getStarName();
this.business = hotel.getBusiness();
this.location = hotel.getLatitude() + ", " + hotel.getLongitude();
this.pic = hotel.getPic();
}
}
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修改回應處理
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| for (SearchHit hit : hits) {
String json = hit.getSourceAsString();
HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
Object[] sortValues = hit.getSortValues();
if (sortValues.length > 0){
Object sortValue = sortValues[0];
hotelDoc.setDistance(sortValue);
}
hotels.add(hotelDoc);
}
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加入廣告飯店
需求：讓指定的飯店在搜尋結果中排名置頂
給指定飯店加入標記，在篩選條件中根據此標記判斷是否提高 function_score
在 HotelDoc 加入廣告標記欄位
用 DSL 給一些飯店加入標記
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| # 加入廣告
POST /hotel/_update/607915
{
"doc": {
"isAD": true
}
}
POST /hotel/_update/728461
{
"doc": {
"isAD": true
}
}
POST /hotel/_update/7094829
{
"doc": {
"isAD": true
}
}
POST /hotel/_update/198323591
{
"doc": {
"isAD": true
}
}
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加入算分函式查詢，修改 basicQuery() 方法
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| private static void basicQuery(RequestParams params, SearchRequest request) {
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
// 輸入內容
String key = params.getKey();
if (key == null || "".equals(key)){
boolQuery.must(QueryBuilders.matchAllQuery());
}else {
boolQuery.must(QueryBuilders.matchQuery("all", key));
}
// brand
if (params.getBrand() != null && !params.getBrand().equals("")){
boolQuery.filter(QueryBuilders.termQuery("brand", params.getBrand()));
}
// starName
if (params.getStarName() != null && !params.getStarName().equals("")){
boolQuery.filter(QueryBuilders.termQuery("starName", params.getStarName()));
}
// city
if (params.getCity() != null && !params.getStarName().equals("")){
boolQuery.filter(QueryBuilders.termQuery("city", params.getCity()));
}
// price
if (params.getMinPrice() != null && params.getMaxPrice() != null){
boolQuery.filter(QueryBuilders
.rangeQuery("price")
.gte(params.getMinPrice())
.lte(params.getMaxPrice())
);
}
// 算分 function_score
FunctionScoreQueryBuilder functionScoreQuery = QueryBuilders.functionScoreQuery(
// 原始查詢
boolQuery,
// 陣列
new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
// 其中一個 function score 元素
new FunctionScoreQueryBuilder.FilterFunctionBuilder(
// 篩選條件
QueryBuilders.termQuery("isAD", true),
// 算分函式
ScoreFunctionBuilders.weightFactorFunction(10)
)
}
);
// 查詢
request.source().query(functionScoreQuery);
}
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