Java High Level REST Client 7.4 for elasticsearch examples
昨天折腾了一下Elasticsearch, 今天把过程记录下来免得忘记。
首先当然是安装，我用的mac, 所以安装很简单:
brew tap elastic/tap
brew install elastic/tap/elasticsearch-full
elasticsearch
搞定。
然后就是按照官方的教程, 用curl把这几个页面上(index, search, aggregations)的命令跑了一遍。 为了免得以后重新打命令，我把这个命令都放到一个reference.sh里面去了，想要跑哪一行，就把那个命令前面的#去掉，然后bash reference.sh就可以了。
最后还折腾了一下官方的Java REST Client 7.4, 其中有一个坑就是Maven Repository页面上写的是7.4.1，但是我在pom.xml里面用7.4.1死活编译不了，我还以为是因为我用了阿里云的maven源，里面没有更新，换成官方的源还是不行，我去官方的源上一看，到今天(2019-10-23)为止, 官方源上最新的版本是7.4.0，所以上面应该写7.4.0.
其它的就没什么了，先搞个project:
mvn -B archetype:generate -DarchetypeGroupId=org.apache.maven.archetypes -DgroupId=com.laogongshuo.es -DartifactId=elasticsearch
cd elasticsearch
然后把依赖关系加到pom.xml里面去:
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.encoding>UTF-8</maven.compiler.encoding>
<java.version>1.8</java.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.4.0</version>
</dependency>
</dependencies>
在src/main/java/com/laogongshuo/es/App.java里面撸一些代码:
package com.laogongshuo.es;
import java.io.IOException;
import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.builder.SearchSourceBuilder;
public class App {
private static final String[] FETCH_FIELDS = {
"account_number",
"balance",
"firstname",
"lastname",
"age",
"gender",
"address",
"employer",
"email",
"city",
"state"
};
public static void matchAll() throws IOException {
RestHighLevelClient client =
new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http")));
SearchRequest searchRequest = new SearchRequest("bank");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(searchSourceBuilder);
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
if (searchResponse.getHits().getTotalHits().value > 0) {
System.out.println(searchResponse.getHits().getTotalHits());
for (SearchHit hit : searchResponse.getHits()) {
System.out.println("Match: ");
for (String fetchField : FETCH_FIELDS) {
System.out.println(" - " + fetchField + " " + hit.getSourceAsMap().get(fetchField));
}
}
} else {
System.out.println("No results matching the criteria.");
}
client.close();
}
public static void search() throws IOException {
RestHighLevelClient client =
new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http")));
SearchRequest searchRequest = new SearchRequest("bank");
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.termQuery("account_number", "49"));
searchRequest.source(sourceBuilder);
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
if (searchResponse.getHits().getTotalHits().value > 0) {
System.out.println(searchResponse.getHits().getTotalHits());
for (SearchHit hit : searchResponse.getHits()) {
System.out.println("Match: ");
for (String fetchField : FETCH_FIELDS) {
System.out.println(" - " + fetchField + " " + hit.getSourceAsMap().get(fetchField));
}
}
} else {
System.out.println("No results matching the criteria.");
}
client.close();
}
public static void main(String[] args) throws IOException {
matchAll();
search();
}
}
最后编译运行：
mvn clean package
mvn exec:java -Dexec.mainClass="com.laogongshuo.es.App"
因为没有在pom.xml里面写执行的mainClass，所以只能这么跑，不过能看到结果就行了。
后续： 在pom.xml中加上下面一段:
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>com.laogongshuo.es.App</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
然后就可以java -jar运行了。
mvn clean compile assembly:single
java -jar target/elasticsearch-1.0-SNAPSHOT-jar-with-dependencies.jar
在match_all后面我用调用一些其它代码：
matchAll();
search();
count();
index();
get();
exist();
delete();
update();
bulk();
info();
这些代码都是根据官方的api, https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-query-builders.html来实现的，没有什么难度，有需要调用其它方法，直接参考官方api就可以了。
文中全部代码都在这里，github, 欢迎star.
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