标签：col target link 组合 odi 为什么 creat book 基本使用
前面几篇文章详细讲解了 ElasticSearch 的搭建以及使用 SpringDataElasticSearch 来完成搜索查询，但是搜索一般都会有搜索关键字高亮的功能，今天我们把它给加上。
本文以及后续 es 系列文章都基于 5.5.3 这个版本的 elasticsearch ，这个版本比较稳定，可以用于生产环境。
SpringDataElasticSearch 的基本使用可以看我的上一篇文章 和我一起打造个简单搜索之SpringDataElasticSearch入门，本文就不再赘述。
前文查询是通过写一个接口来继承 ElasticsearchRepository 来实现的，但是如果要实现高亮，我们就不能这样做了，我们需要使用到 ElasticsearchTemplate来完成。
查看这个类的源码
public class ElasticsearchTemplate implements ElasticsearchOperations, ApplicationContextAware {
...
}可以看到，ElasticsearchTemplate 实现了接口 ApplicationContextAware，所以这个类是被 Spring 管理的，可以在类里面直接注入使用。
代码如下:
@Slf4j
@Component
public class HighlightBookRepositoryTest extends EsSearchApplicationTests {
@Autowired
private ElasticsearchTemplate elasticsearchTemplate;
@Resource
private ExtResultMapper extResultMapper;
@Test
public void testHighlightQuery() {
BookQuery query = new BookQuery();
query.setQueryString("穿越");
// 复合查询
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
// 以下为查询条件, 使用 must query 进行查询组合
MultiMatchQueryBuilder matchQuery = QueryBuilders.multiMatchQuery(query.getQueryString(), "name", "intro", "author");
boolQuery.must(matchQuery);
PageRequest pageRequest = PageRequest.of(query.getPage() - 1, query.getSize());
NativeSearchQuery searchQuery = new NativeSearchQueryBuilder()
.withQuery(boolQuery)
.withHighlightFields(
new HighlightBuilder.Field("name").preTags("<span style=\"color:red\">").postTags("</span>"),
new HighlightBuilder.Field("author").preTags("<span style=\"color:red\">").postTags("</span>"))
.withPageable(pageRequest)
.build();
Page<Book> books = elasticsearchTemplate.queryForPage(searchQuery, Book.class, extResultMapper);
books.forEach(e -> log.info("{}", e));
// <span style="color:red">穿越</span>小道人
}
}注意这里 的
Page<Book> books = elasticsearchTemplate.queryForPage(searchQuery, Book.class, extResultMapper);这里返回的是分页对象。
查询方式和上文的差不多，只不过是是 Repository 变成了 ElasticsearchTemplate，操作方式也大同小异。
这里用到了 ExtResultMapper，请接着看下文。
ResultMapper 是用于将 ES 文档转换成 Java 对象的映射类，因为 SpringDataElasticSearch 默认的的映射类 DefaultResultMapper 不支持高亮，因此，我们需要自己定义一个 ResultMapper。
复制 DefaultResultMapper 类，重命名为 ExtResultMapper，对构造方法名称修改为正确的值。
新增一个方法，用于将高亮的内容赋值给需要转换的 Java 对象内。
在 mapResults 方法内调用这个方法。
注意：这个类可以直接拷贝到你的项目中直接使用！
我写这么多，只是想说明为什么这个类是这样的。
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import org.apache.commons.beanutils.PropertyUtils;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.get.MultiGetItemResponse;
import org.elasticsearch.action.get.MultiGetResponse;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.common.text.Text;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHitField;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.springframework.data.domain.Pageable;
import org.springframework.data.elasticsearch.ElasticsearchException;
import org.springframework.data.elasticsearch.annotations.Document;
import org.springframework.data.elasticsearch.annotations.ScriptedField;
import org.springframework.data.elasticsearch.core.AbstractResultMapper;
import org.springframework.data.elasticsearch.core.DefaultEntityMapper;
import org.springframework.data.elasticsearch.core.EntityMapper;
import org.springframework.data.elasticsearch.core.aggregation.AggregatedPage;
import org.springframework.data.elasticsearch.core.aggregation.impl.AggregatedPageImpl;
import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
import org.springframework.data.mapping.context.MappingContext;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.nio.charset.Charset;
import java.util.*;
/**
* 类名称：ExtResultMapper
* 类描述：自定义结果映射类
* 创建人：WeJan
* 创建时间：2018-09-13 20:47
*/
@Component
public class ExtResultMapper extends AbstractResultMapper {
private MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext;
public ExtResultMapper() {
super(new DefaultEntityMapper());
}
public ExtResultMapper(MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext) {
super(new DefaultEntityMapper());
this.mappingContext = mappingContext;
}
public ExtResultMapper(EntityMapper entityMapper) {
super(entityMapper);
}
public ExtResultMapper(
MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext,
EntityMapper entityMapper) {
super(entityMapper);
this.mappingContext = mappingContext;
}
@Override
public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable) {
long totalHits = response.getHits().totalHits();
List<T> results = new ArrayList<>();
for (SearchHit hit : response.getHits()) {
if (hit != null) {
T result = null;
if (StringUtils.hasText(hit.sourceAsString())) {
result = mapEntity(hit.sourceAsString(), clazz);
} else {
result = mapEntity(hit.getFields().values(), clazz);
}
setPersistentEntityId(result, hit.getId(), clazz);
setPersistentEntityVersion(result, hit.getVersion(), clazz);
populateScriptFields(result, hit);
// 高亮查询
populateHighLightedFields(result, hit.getHighlightFields());
results.add(result);
}
}
return new AggregatedPageImpl<T>(results, pageable, totalHits, response.getAggregations(), response.getScrollId());
}
private <T> void populateHighLightedFields(T result, Map<String, HighlightField> highlightFields) {
for (HighlightField field : highlightFields.values()) {
try {
PropertyUtils.setProperty(result, field.getName(), concat(field.fragments()));
} catch (InvocationTargetException | IllegalAccessException | NoSuchMethodException e) {
throw new ElasticsearchException("failed to set highlighted value for field: " + field.getName()
+ " with value: " + Arrays.toString(field.getFragments()), e);
}
}
}
private String concat(Text[] texts) {
StringBuffer sb = new StringBuffer();
for (Text text : texts) {
sb.append(text.toString());
}
return sb.toString();
}
private <T> void populateScriptFields(T result, SearchHit hit) {
if (hit.getFields() != null && !hit.getFields().isEmpty() && result != null) {
for (java.lang.reflect.Field field : result.getClass().getDeclaredFields()) {
ScriptedField scriptedField = field.getAnnotation(ScriptedField.class);
if (scriptedField != null) {
String name = scriptedField.name().isEmpty() ? field.getName() : scriptedField.name();
SearchHitField searchHitField = hit.getFields().get(name);
if (searchHitField != null) {
field.setAccessible(true);
try {
field.set(result, searchHitField.getValue());
} catch (IllegalArgumentException e) {
throw new ElasticsearchException("failed to set scripted field: " + name + " with value: "
+ searchHitField.getValue(), e);
} catch (IllegalAccessException e) {
throw new ElasticsearchException("failed to access scripted field: " + name, e);
}
}
}
}
}
}
private <T> T mapEntity(Collection<SearchHitField> values, Class<T> clazz) {
return mapEntity(buildJSONFromFields(values), clazz);
}
private String buildJSONFromFields(Collection<SearchHitField> values) {
JsonFactory nodeFactory = new JsonFactory();
try {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
JsonGenerator generator = nodeFactory.createGenerator(stream, JsonEncoding.UTF8);
generator.writeStartObject();
for (SearchHitField value : values) {
if (value.getValues().size() > 1) {
generator.writeArrayFieldStart(value.getName());
for (Object val : value.getValues()) {
generator.writeObject(val);
}
generator.writeEndArray();
} else {
generator.writeObjectField(value.getName(), value.getValue());
}
}
generator.writeEndObject();
generator.flush();
return new String(stream.toByteArray(), Charset.forName("UTF-8"));
} catch (IOException e) {
return null;
}
}
@Override
public <T> T mapResult(GetResponse response, Class<T> clazz) {
T result = mapEntity(response.getSourceAsString(), clazz);
if (result != null) {
setPersistentEntityId(result, response.getId(), clazz);
setPersistentEntityVersion(result, response.getVersion(), clazz);
}
return result;
}
@Override
public <T> LinkedList<T> mapResults(MultiGetResponse responses, Class<T> clazz) {
LinkedList<T> list = new LinkedList<>();
for (MultiGetItemResponse response : responses.getResponses()) {
if (!response.isFailed() && response.getResponse().isExists()) {
T result = mapEntity(response.getResponse().getSourceAsString(), clazz);
setPersistentEntityId(result, response.getResponse().getId(), clazz);
setPersistentEntityVersion(result, response.getResponse().getVersion(), clazz);
list.add(result);
}
}
return list;
}
private <T> void setPersistentEntityId(T result, String id, Class<T> clazz) {
if (mappingContext != null && clazz.isAnnotationPresent(Document.class)) {
ElasticsearchPersistentEntity<?> persistentEntity = mappingContext.getRequiredPersistentEntity(clazz);
ElasticsearchPersistentProperty idProperty = persistentEntity.getIdProperty();
// Only deal with String because ES generated Ids are strings !
if (idProperty != null && idProperty.getType().isAssignableFrom(String.class)) {
persistentEntity.getPropertyAccessor(result).setProperty(idProperty, id);
}
}
}
private <T> void setPersistentEntityVersion(T result, long version, Class<T> clazz) {
if (mappingContext != null && clazz.isAnnotationPresent(Document.class)) {
ElasticsearchPersistentEntity<?> persistentEntity = mappingContext.getPersistentEntity(clazz);
ElasticsearchPersistentProperty versionProperty = persistentEntity.getVersionProperty();
// Only deal with Long because ES versions are longs !
if (versionProperty != null && versionProperty.getType().isAssignableFrom(Long.class)) {
// check that a version was actually returned in the response, -1 would indicate that
// a search didn‘t request the version ids in the response, which would be an issue
Assert.isTrue(version != -1, "Version in response is -1");
persistentEntity.getPropertyAccessor(result).setProperty(versionProperty, version);
}
}
}
}注意这里使用到了 PropertyUtils ，需要引入一个 Apache 的依赖。
<dependency>
<groupId>commons-beanutils</groupId>
<artifactId>commons-beanutils</artifactId>
<version>1.9.3</version>
</dependency>自定义 ResultMapper 写好之后，添加 @Component 注解，表示为 Spring 的一个组件，在类中进行注入使用即可。
本文示例项目地址：https://github.com/Mosiki/SpringDataElasticSearchQuickStartExample
欢迎来信，给我写信
和我一起打造个简单搜索之SpringDataElasticSearch关键词高亮
标签：col target link 组合 odi 为什么 creat book 基本使用
原文地址：https://www.cnblogs.com/vcmq/p/9966693.html
