elasticsearch两个字段对比（近距离感受一下Elasticsearch的CRUD）
elasticsearch两个字段对比（近距离感受一下Elasticsearch的CRUD）<pre class="prettyprint hljs go" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto;
在基本了解并在Kibana Dev Tools控制台操作Elasticsearch的查询语法之后，是时候在实际应用中使用ES了。那么怎么在Java中使用ES呢？
可以有下面几种方式来实现：
- Transport Client
- java High Level REST Client
- Spring Data Elasticsearch
TransportClient 可用于老版本的Elasticsearch；新版本建议使用 Java High Level REST Client （向下兼容）；当然还可以使用Spring Data提供的 Spring Data Elasticsearch 。
本文先只介绍一下 Transport Client API，后面慢慢来 REST Client 和 Spring Data Elasticsearch 。
Transport Client注意：在7.0.0中弃用。不推荐使用TransportClient，而推荐使用Java High Level REST Client，并将在Elasticsearch 8.0中将其删除。
Elasticsearch 8.x版本将会删除 TransportClient 。这里为什么还要介绍一下它的API呢？毕竟有些老铁用的还是以前的版本，而且API很多地方是相通的，那就多学习一点吧！
引入jar包<pre class="prettyprint hljs xml" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"><dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>transport</artifactId>
<version>7.9.0</version>
</dependency>
注意版本号，一定要和你安装的Elasticsearch的版本号一致。
创建到ES的连接必须得先连接到ES才能进行一系列的API测试，连接的代码如下：
<pre class="prettyprint hljs go" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">// 创建连接
TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
.addTransportAddress(
new TransportAddress(
InetAddress.getByName("localhost") 9300));
//一系列操作...
//关闭连接
client.close();
可以看到， TransportClient 是deprecated，弃用了，我用的是ES 7.9版本，它在7.0.0中被弃用。
注意：
- InetAddress.getByName("localhost") 9300) 这里绑定的端口 9300 是通讯端口，不是服务端口（服务端口是9200）
- 如果使用与 Elasticsearch 不同的集群名称，则必须设置集群名称：
<pre class="prettyprint hljs dockerfile" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Settings settings = Settings.builder()
.put("Cluster.name" "myClusterName").build();
TransportClient client = new PreBuiltTransportClient(settings);
//Add transport addresses and do something with the client...
比如我的：
单节点ES默认的集群名称就是 elasticsearch 。
Index API索引API允许将输入的JSON文档索引到特定索引中并使之可搜索。
生成JSON文档生成json文档有很多种方法，比如：
- 手动构造
<pre class="prettyprint hljs vbscript" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">String json = "{"
"\"user\":\"kimchy\" "
"\"postDate\":\"2013-01-30\" "
"\"message\":\"trying out Elasticsearch\""
"}";
- 使用Map
<pre class="prettyprint hljs javascript" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Map<String Object> json = new HashMap<String Object>();
json.put("user" "kimchy");
json.put("postDate" new Date());
json.put("message" "trying out Elasticsearch");
Map是一个key：values对集合。它可以表示一个JSON结构。
- Jackson
可以使用Jackson将bean序列化为JSON。
<pre class="prettyprint hljs verilog" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">import com.fasterxml.jackson.databind.*;
// instance a json mapper
ObjectMapper mapper = new ObjectMapper(); // create once reuse
// generate json
byte[] json = mapper.writeValueAsBytes(yourbeaninstance);
- fastjson
com.alibaba.fastjson.JSONObject
它的转换方法，包括Java对象转成JSON串、JSON对象，JSON串转成java对象、JSON对象，JSON对象转换Java对象、JSON串等。
<pre class="prettyprint hljs xquery" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">String stuString = "{\"age\":2 \"name\":\"公众号行百里er\" \"sex\":\"m\"}";
//JSON字符串转换成JSON对象
JSONObject jsonObject1 = JSONObject.parseObject(stuString);
- 等等
当然，Elasticsearch 也提供了内置的帮助器以生成JSON内容：
<pre class="prettyprint hljs vbscript" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">XContentBuilder builder = jsonBuilder()
.startObject()
.field("user" "kimchy")
.field("postDate" new Date())
.field("message" "trying out Elasticsearch")
.endObject()
增删改查APICreate 创建索引、文档相关API
向索引添加文档，如果索引不存在，则该API会自动给我们创建索引
<pre class="prettyprint hljs dart" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">@Test
@SneakyThrows
void esCRUD() {
// 创建连接
TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
.addTransportAddress(
new TransportAddress(
InetAddress.getByName("localhost") 9300));
//增
//create(client);
//查
//get(client);
//getAll(client);
//改
//update(client);
//删
delete(client);
}
@SneakyThrows
void create(TransportClient client){
for (int i = 0; i < 5; i ) {
XContentBuilder builder = XContentFactory.jsonBuilder()
.startObject()
.field("empName" "name" i)
.field("age" new Random().nextInt(100))
.field("createTime" new Date())
.endObject();
IndexResponse response = client.prepareIndex("emp" "_doc" String.valueOf(i))
.setSource(builder)
.get();
// //还可以不指定id
// IndexResponse response = client.prepareIndex("emp" "_doc")
// .setSource(builder)
// .get();
System.out.println(response.getResult());
}
}
这里我用prepareIndex指定id和不指定id分别执行了一遍，所以应该有10条文档产生。
通过Kibana控制台验证一下执行结果：
结果是执行成功的！
正好，用查询API来验证一下。
GET API 查询单个、所有文档相关API代码生成的时候，又生成id为0~4的文档，就查一下id为3的吧先：
<pre class="prettyprint hljs typescript" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void get(TransportClient client) {
GetResponse response = client.prepareGet("emp" "_doc" "3").get();
String index = response.getIndex();//获取索引名称
String type = response.getType();//获取索引类型
String id = response.getId();//获取索引id
System.out.println("index:" index);
System.out.println("type:" type);
System.out.println("id:" id);
System.out.println(response.getSourceAsString());
}
执行成功！
查询所有的API试一下：
<pre class="prettyprint hljs vbscript" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void getAll(TransportClient client) {
SearchResponse response = client.prepareSearch("emp").get();
SearchHits searchHits = response.getHits();
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
String res = hit.getSourceAsString();
System.out.println("res" res);
}
}
OK，成功查询出所有文档。
这里可以对比Kibana Dev Tools控制台返回的json结果，
<pre class="prettyprint hljs xquery" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">{
"took" : 134
"timed_out" : false
"_shards" : {
"total" : 1
"successful" : 1
"skipped" : 0
"failed" : 0
}
"hits" : {
"total" : {
"value" : 10
"relation" : "eq"
}
"max_score" : 1.0
"hits" : [
{
"_index" : "emp"
"_type" : "_doc"
"_id" : "ze2qFnQBZf6fz3EOVZFP"
"_score" : 1.0
"_source" : {
"empName" : "name0"
"age" : 35
"createTime" : "2020-08-22T14:54:54.999Z"
}
}
// 中间的结果略...
{
"_index" : "emp"
"_type" : "_doc"
"_id" : "4"
"_score" : 1.0
"_source" : {
"empName" : "name4"
"age" : 56
"createTime" : "2020-08-22T15:05:58.480Z"
}
}
]
}
}
Java API的一些方法名和ES查询结果JSON先关字段一般能对的上，如果平时控制台操作比较熟悉的话，再来使用API其实很简单了！
Update API修改id为3的记录，将其name改为鲁班7号：
<pre class="prettyprint hljs cs" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void update(TransportClient client) {
try {
UpdateResponse response = client.prepareUpdate("emp" "_doc" "3")
.setDoc(XContentFactory.jsonBuilder()
.startObject()
.field("name" "鲁班7号")
.endObject())
.get();
System.out.println(response.getResult());
} catch (IOException e) {
e.printStackTrace();
}
}
验证一下：
删除id为3的文档记录：
<pre class="prettyprint hljs cs" style="padding: 0.5em; font-family: Menlo Monaco Consolas "Courier New" monospace; color: rgb(68 68 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246 246 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void delete(TransportClient client) {
DeleteResponse response = client.prepareDelete("emp" "_doc" "3").get();
System.out.println(response.getResult());
}
