最近在网络爬虫、nlp群320349384中，对es搜索应用研发有所增加，在此进一步介绍搜索引擎应用研发的经典操作增删改查，由于在此应用中改的部分是相对很少的，故在此只讲增、查、删，即添加索引、条件检索、索引删除。
一、添加索引
添加索引的步骤包括
A、es搜索客户端创建
B、要添加的目标数据
C、将目标数据转化为可索引对象
D、将索引对象（集合）通过A中的client发送给服务器端进行实际的索引操作。
下面仅以jest第三方包的api方式解决以上提到的步骤
A步代码：
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B步代码:
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//将任意对象要索引的数据对象，转化为可索引地象
private
static
List<Index> convertToIndexList(List pojoList) {
List<Index> indexList =
new
ArrayList<Index>();
Index index =
null
;
for
(Object obj : pojoList) {
index =
new
Index.Builder(obj).build();
indexList.add(index);
}
return
indexList;
}
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C和D步代码：
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// 批量增加对象集合数据加进ES索引中,indexName为索引名称，typeName为索引类型，indexList为批量可索引对象集合
public
void
addIndexToES(String indexName, String typeName,
List<Index> indexList) {
if
(indexList ==
null
|| indexList.isEmpty()) {
return
;
}
// 通过manager类得到jest client
ESJestClientPojo esJestClientPojo = esClientManager.getJestClient();
// 构建索引名称、索引类型的builder，此为加入索引数据的前提条件
Bulk.Builder builder =
new
Bulk.Builder().defaultIndex(indexName)
.defaultType(typeName);
// 每个index就是一个可索引对象，将其批量构建成json串数据
builder.addAction(indexList).build();
// 构造进可执行实质索引操作的批量操作工具类中
Bulk bulk2 =
new
Bulk(builder);
// 遇到time out时，进行重新请求
int
repeat_time =
0
;
int
continious_exception_count =
0
;
while
(repeat_time <= SystemParas.es_index_fail_max_time) {
try
{
//实质执行将数据转化为成索引的索引操作
esJestClientPojo.getJestClient().execute(bulk2);
logger.info(esJestClientPojo.getPrefix_sign() +
"index ok!"
);
break
;
}
catch
(SocketTimeoutException timeout) {
repeat_time++;
logger.info(esJestClientPojo.getPrefix_sign()
+
"occur timeout when indexing,will do it try again!"
);
try
{
Thread.sleep(SystemParas.es_index_fail_waitting_time);
}
catch
(Exception e) {
e.printStackTrace();
}
continious_exception_count++;
// 更换新的jest client
if
(continious_exception_count == SystemParas.es_client_continious_exception_count_max) {
esJestClientPojo = esClientManager
.getNewClient(esJestClientPojo);
}
}
catch
(Exception e) {
repeat_time++;
logger.info(esJestClientPojo.getPrefix_sign()
+
"occur unknown error when indexing,will do it try again!"
);
e.printStackTrace();
try
{
Thread.sleep(SystemParas.es_index_fail_waitting_time);
}
catch
(Exception sleepException) {
sleepException.printStackTrace();
}
continious_exception_count++;
// 更换新的jest client
if
(continious_exception_count == SystemParas.es_client_continious_exception_count_max) {
esJestClientPojo = esClientManager
.getNewClient(esJestClientPojo);
}
}
if
(repeat_time > SystemParas.es_index_fail_max_time) {
logger.info(
"the error index times is to the max try,will abandom this data!"
);
break
;
}
}
esClientManager.pushJestClient(esJestClientPojo);
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二、条件检索
步骤包括
A、创建客户端client对象，类同于一中的。
B、构建查询对象SearchSourceBuilder
C、搜索操作及结果转化
其中B步代码：
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// 通过各种查询条件构建可查询对象SearchSourceBuilder,其逻辑类似于sql查询
private
static
SearchSourceBuilder getSearchSourceBuilder(
SearchConditionPojo searchConditionPojo) {
List<SearchConditionItem> searchConditionItemList =
null
;
if
(searchConditionPojo ==
null
|| StringOperatorUtil
.isBlankCollection(searchConditionItemList = searchConditionPojo
.getSearchConditionList())) {
return
null
;
}
// 布尔查询
BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
// 把list转化为es searchbuilder
for
(SearchConditionItem conditionPojo : searchConditionItemList) {
// and查询构建
if
(conditionPojo.getSearchType() == SearchType.AND) {
boolQueryBuilder = boolQueryBuilder.must(QueryBuilders
.termQuery(conditionPojo.getName(),
conditionPojo.getValue()));
}
else
if
(conditionPojo.getSearchType() == SearchType.RANGE) {
// 范围查询构建
boolQueryBuilder = boolQueryBuilder.must(QueryBuilders
.rangeQuery(conditionPojo.getName())
.from(conditionPojo.getFromObj())
.to(conditionPojo.getToObj())
.includeLower(conditionPojo.isIncludeLower())
.includeUpper(conditionPojo.isIncludeHigher()));
}
}
SearchSourceBuilder searchSourceBuilder =
new
SearchSourceBuilder();
searchSourceBuilder.query(boolQueryBuilder);
// 排序字段构建
for
(SearchConditionItem conditionPojo : searchConditionItemList) {
if
(conditionPojo.getSearchType() == SearchType.SORT) {
if
(conditionPojo.getSortOrderEnum().toString()
.equals(SortOrder.ASC.toString())) {
searchSourceBuilder.sort(conditionPojo.getName(),
SortOrder.ASC);
}
else
{
searchSourceBuilder.sort(conditionPojo.getName(),
SortOrder.DESC);
}
}
}
// 选择搜索命中结果集的起始偏移量及多少个元素
searchSourceBuilder.from(searchConditionPojo.getStart());
searchSourceBuilder.size(searchConditionPojo.getPageSize());
return
searchSourceBuilder;
}
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C步代码：
有两种结果的返回形式，即对象和json串形式
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// 通过搜索返回结果，以对象形式
public
List<T> search4RetObj(String indexName, String indexType,
SearchSourceBuilder searchSourceBuilder, Class<T> resultClass) {
SearchResult searchResult = search(indexName, indexType,
searchSourceBuilder);
if
(searchResult ==
null
) {
return
null
;
}
List<SearchResult.Hit<T, Void>> hits = searchResult
.getHits(resultClass);
List<T> resultClassList =
new
LinkedList<T>();
Iterator<Hit<T, Void>> hitsList = hits.iterator();
while
(hitsList.hasNext()) {
resultClassList.add(hitsList.next().source);
}
return
resultClassList;
}
// 通过搜索返回结果，以json串形式
public
String search4RetJson(String indexName, String indexType,
SearchSourceBuilder searchSourceBuilder, Class<T> resultClass) {
SearchResult searchResult = search(indexName, indexType,
searchSourceBuilder);
if
(searchResult ==
null
) {
return
null
;
}
String jsonResult = searchResult.getJsonString();
return
jsonResult;
}
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三、索引删除
有多种情况，如直接删除某索引库，或是按指定条件删除索引
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//直接删除指定索引库
public
void
deleteByIndexName(String indexName) {
ESJestClientPojo esJestClientPojo = esClientManager.getJestClient();
DeleteIndex dIndex =
new
DeleteIndex(
new
DeleteIndex.Builder(indexName));
// 遇到time out时，进行重新请求
int
repeat_time =
0
;
while
(repeat_time < SystemParas.es_index_fail_max_time) {
try
{
esJestClientPojo.getJestClient().execute(dIndex);
logger.info(esJestClientPojo.getPrefix_sign()
+
"delete index ok!"
);
break
;
}
catch
(SocketTimeoutException timeout) {
repeat_time++;
logger.info(esJestClientPojo.getPrefix_sign()
+
"occur timeout when deleteByIndexName,will do it try again!"
);
try
{
Thread.sleep(SystemParas.es_index_fail_waitting_time);
}
catch
(Exception e) {
e.printStackTrace();
}
continue
;
}
catch
(Exception e) {
e.printStackTrace();
logger.info(esJestClientPojo.getPrefix_sign()
+
"to add one item index occur error,will jump the item!"
);
break
;
}
}
esClientManager.pushJestClient(esJestClientPojo);
}
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/**
* 以下是ES端提供的client来操作索引端,通过构建QueryBuilder来达到按指定条件来删除索引
* @param args
*/
public
void
deleteIndexByQuery(String indexName, QueryBuilder queryBuilder) {
ESSelfClientPojo esClientPojo = esClientManager.getESClient();
// 遇到time out时，进行重新请求
int
repeat_time =
0
;
while
(repeat_time < SystemParas.es_index_fail_max_time) {
try
{
esClientPojo.getEsClient().prepareDeleteByQuery(indexName)
.setQuery(queryBuilder).execute().actionGet();
logger.info(esClientPojo.getPrefix_sign() +
"delete index ok!"
);
break
;
}
catch
(Exception e) {
e.printStackTrace();
logger.info(esClientPojo.getPrefix_sign()
+
"delete index fail,please try again!"
);
}
repeat_time++;
}
esClientManager.pushESClient(esClientPojo);
}
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时间原因就暂写到这，有发现问题欢迎交流。交流促进成长，共享成就未来，欢迎加入网络技术、nlp群320349384，共同交流进步。