此文是ElasticSearch入门的第三篇，主要介绍下ES的Java API开发。
1. 环境准备JDK ：1.8
ES ：7.15.2（es的客户端版本要和本地部署的服务端版本保持一致）
IDEA：2020.1
新建一个maven项目，导入如下的pom文件
2. 代码 2.1 创建客户端连接org.elasticsearch.client transport 7.15.2 org.elasticsearch.client elasticsearch-rest-high-level-client 7.15.2 org.elasticsearch.client elasticsearch-rest-client 7.15.2 org.apache.logging.log4j log4j-core 2.9.1 junit junit 4.12 test org.testng testng 6.14.3 test com.alibaba fastjson 1.2.47 org.junit.jupiter junit-jupiter RELEASE compile org.junit.jupiter junit-jupiter RELEASE compile
创建es的客户端有两种方式，一种是通过TransportClient方式，使用内部通信端口；另一种是通过RestHighLevelClient方式，使用http端口，是目前ES官方主推的模式。
因为笔者是学习状态，本文主要还是通过TransportClient方式，两种方式可以转换
private TransportClient transportClient;
private RestHighLevelClient restHighLevelClient;
@BeforeEach
public void createClinet() throws UnknownHostException {
Settings settings = Settings.builder()
.put("cluster.name", "zero")
.put("client.transport.sniff", "false")//本地测试要设置成false
.build();
transportClient = new PreBuiltTransportClient(settings)
.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9300))//内部通信端口
.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9301))//内部通信端口
.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9302));//内部通信端口
System.out.println("TransportClient 连接成功");
restHighLevelClient = new RestHighLevelClient(
RestClient.builder(
new HttpHost("localhost", 9200, "http"),//http的通信端口
new HttpHost("localhost", 8200, "http"),//http的通信端口
new HttpHost("localhost",8000,"http")));//http的通信端口
System.out.println("RestHighLevelClient 连接成功");
}
2.2 关闭客户端连接
@AfterEach
public void closeClinet(){
try {
transportClient.close();
System.out.println("TransportClient 连接关闭成功");
restHighLevelClient.close();
System.out.println("RestHighLevelClient 连接关闭成功");
} catch (IOException e) {
e.printStackTrace();
}
}
2.3 实际操作
@Test
public void createIndex_1() {
//
transportClient.admin().indices().prepareCreate("mytest_index_1").get();
System.out.println("创建Index成功");
IndexRequest indexRequest = new IndexRequest("mytest_index_1");
indexRequest.type("_doc");
indexRequest.id("1");
indexRequest.source("{" + ""name": "商品2","
+ ""price": "10"," + ""number": "10"" + "}", XContentType.JSON);
try {
restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
@Test
public void createIndex_2() throws Exception {
HashMap jsonMap = new HashMap();
jsonMap.put("name", "zero");
jsonMap.put("sex", "1");
jsonMap.put("age", "25");
jsonMap.put("address", "hf");
IndexResponse indexResponse = transportClient.prepareIndex("mytest_index_2", "doc", "2")
.setSource(jsonMap)
.get();
System.out.println("创建Index成功");
}
@Test
public void deleteIndex(){
transportClient.admin().indices().prepareDelete("mytest_index_2").get();
System.out.println("删除索引成功");
}
@Test
public void getSearch(){
GetResponse documentField = transportClient.prepareGet("employee","_doc","1").get();
//直接输出string类型的结果字符串
System.out.println(documentField.getSourceAsString());
//输出index、type、id等内部属性字段值
String index = documentField.getIndex();
String type_ = documentField.getType();
String id = documentField.getId();
System.out.println("index: "+index+", type: "+type_+", id: "+id);
//输出自定的字段的结果
Map source = documentField.getSource();
for(String field:source.keySet()){
System.out.println(field +" : "+source.get(field));
}
//输出某个自定义字段的值
String name = (String) documentField.getSource().get("name");
System.out.println(name);
}
@Test
public void searchAllData(){
SearchResponse searchResponse = transportClient.prepareSearch("employee")
// .setTypes("_doc")
.setQuery(new MatchAllQueryBuilder())
.get();
SearchHits searchHits = searchResponse.getHits();
SearchHit[] hits = searchHits.getHits();
for(SearchHit hit:hits){
String sourceString = hit.getSourceAsString();
System.out.println(sourceString);
};
}
@Test
public void rangeQuery(){
SearchResponse searchResponse = transportClient.prepareSearch("employee")
.setQuery(new RangeQueryBuilder("sal").gte(10000).lte(20000))
.get();
SearchHits hits = searchResponse.getHits();
SearchHit[] hits1 = hits.getHits();
for (SearchHit documentFields : hits1) {
System.out.println(documentFields.getSourceAsString());
}
}
@Test
public void termQuery(){
String[] include_source = {"name","age","job"};
String[] exclude_a = null;
String[] exclude_b = {"age"};
SearchResponse searchResponse = transportClient.prepareSearch("employee")
.setQuery(new TermQueryBuilder("job", "java"))
// .setFetchSource(include_source,exclude_a)//设置只返回指定的字段或者不回哪些字段,
.setFetchSource(include_source,exclude_b) //设置不返回age
.get();
SearchHits hits = searchResponse.getHits();
SearchHit[] hits1 = hits.getHits();
for (SearchHit documentFields : hits1) {
System.out.println(documentFields.getSourceAsString());
}
}
@Test
public void fuzzy_search(){
SearchResponse searchResponse = transportClient.prepareSearch("employee")
.setQuery(new FuzzyQueryBuilder("job","jaVA").fuzziness(Fuzziness.TWO))
.get();
SearchHits searchHit = searchResponse.getHits();
SearchHit[] hits = searchHit.getHits();
for (SearchHit hit:hits) {
System.out.println(hit.getSourceAsString());
}
}
@Test
public void boolQuery(){
int pageSize = 3;
int pageNum = 2;
int startNum = (pageNum-1)*pageSize;
TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("job","html");
RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("sal").gt("10000").lt("25000");
FuzzyQueryBuilder fuzzyQueryBuilder = QueryBuilders.fuzzyQuery("gender","fe").fuzziness(Fuzziness.ONE);
SearchResponse searchResponse = transportClient.prepareSearch("employee")
.setQuery(QueryBuilders.boolQuery().must(termQueryBuilder)
.should(QueryBuilders.boolQuery().must(rangeQueryBuilder).must(fuzzyQueryBuilder)))
.addSort("id",SortOrder.ASC)
.setFrom(startNum)
.setSize(pageSize)
.get();
SearchHits searchHit = searchResponse.getHits();
SearchHit[] hits = searchHit.getHits();
for (SearchHit hit:hits) {
System.out.println(hit.getSourceAsString());
}
}
@Test
public void pageQuery(){
int pageSize = 5;
int pageNum = 1;
int startNum = (pageNum-1)*pageSize;
SearchResponse searchResponse = transportClient.prepareSearch("employee")
.setQuery(QueryBuilders.matchAllQuery())
.addSort("id", SortOrder.ASC)
.setSize(pageSize)
.setFrom(startNum)
.get();
SearchHits searchHits = searchResponse.getHits();
SearchHit[] hits = searchHits.getHits();
for(SearchHit searchHit:hits){
System.out.println(searchHit.getSourceAsString());
}
}
