关于版本
| 内容 | 版本 |
|---|---|
| Elasticsearch版本 | 7.2.0 |
| JAVA依赖版本 | 7.2.1 |
Elasticsearch 7.x 和之前版本有相当大的变化，所以本篇内容尤其是JAVA代码的操作对于使用旧版本的同学帮助可能不大。因为本人主要是JAVA开发，在介绍相关操作的时候会附带JAVA代码操作的逻辑。
新增文档
完成了索引和映射的创建之后，我们就可以向ES实例中插入数据。
http请求
ES插入数据的时候，可以选择一个ID作为这次插入文档的ID来使用，当然不设置ID的时候系统会自动生成一个
- 指定ID格式
请求地址
PUT localhost:9200/test_city_info/_doc/1
请求参数
{
"name": "北京",
"population": "特大城市",
"desc": "首都",
"gdp": "万亿级",
"province": "北京",
"college": "清华、北大",
"celebrity": "老舍"
}
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 0,
"_primary_term": 3
}
使用自己的id需要注意一件事情。当指定的id在es中已经存在的时候，这个时候尝试使用上面的操作，系统会执行更新操作，使用新的文档覆盖掉之前的文档。假如你为了避免因为误操作而导致错误更新，可以在操作的时候指定操作类型op_type=create。这个时候系统检测到你对一个已经存在的ID进行新增操作的时候，会抛出异常
localhost:9200/test_city_info/_doc/1?op_type=create
此时尝试保存文档到已经存在的id中的时候会抛出异常
{
"error": {
"root_cause": [
{
"type": "version_conflict_engine_exception",
"reason": "[1]: version conflict, document already exists (current version [6])",
"index_uuid": "ljfFHhspSSmGaBVD3PHjbA",
"shard": "0",
"index": "test_city_info"
}
],
"type": "version_conflict_engine_exception",
"reason": "[1]: version conflict, document already exists (current version [6])",
"index_uuid": "ljfFHhspSSmGaBVD3PHjbA",
"shard": "0",
"index": "test_city_info"
},
"status": 409
}
- 不指定ID格式
不指定插入id的时候系统会默认生成一个id
POST localhost:9200/test_city_info/_doc
请求参数
{
"name": "上海",
"population": "特大城市",
"desc": "经济中心、大城市",
"gdp": "万亿级",
"province": "上海",
"college": "复旦大学",
"celebrity": "黄炎培"
}
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "6MEczm0BIQZGGtiybqNs",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 1,
"_primary_term": 3
}
在新增文档的时候，当你尝试向一个不存在的索引插入数据的时候，会发现系统并不会发生错误，而是直接创建一个默认的索引和映射。这个时候除了数据被保存下来，es中也会多一个新的索引和映射。有的时候这些操作可能并不是我们故意实现的。为了避免系统创建过多错误的索引，这个时候假如不希望es自动创建索引的话，需要修改其action.auto_create_index参数
PUT localhost:9200/_cluster/settings
HEAD Content-Type:application/json
参数
{
"persistent": {
"action.auto_create_index": "false"
}
}
创建文档的java代码
public static void createDoc() throws IOException {
XContentBuilder builder = XContentFactory.jsonBuilder();
builder.startObject();
builder.field("name", "北京");
builder.field("population", "特大城市");
builder.field("desc", "首都");
builder.field("gdp", "万亿级");
builder.field("province", "北京");
builder.field("college", "清华、北大");
builder.field("celebrity", "老舍");
builder.endObject();
IndexRequest indexRequest = new IndexRequest("test_city_info")
.id("1").source(builder);
IndexResponse indexResponse = getClient() .index(indexRequest, RequestOptions.DEFAULT);
}
查询文档
es使用_doc和GET请求方式查询已经保存的文档。
http请求
GET localhost:9200/test_city_info/_doc/6MEczm0BIQZGGtiybqNs
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "6MEczm0BIQZGGtiybqNs",
"_version": 1,
"_seq_no": 1,
"_primary_term": 3,
"found": true,
"_source": {
"name": "上海",
"population": "特大城市",
"desc": "经济中心、大城市",
"gdp": "万亿级",
"province": "上海",
"college": "复旦大学",
"celebrity": "黄炎培"
}
}
查询文档java代码
public static void queryDoc() throws IOException {
GetRequest getRequest = new GetRequest(
"test_city_info", //索引名称
"1"); //文档id
GetResponse response = getClient().get(getRequest, RequestOptions.DEFAULT);
Map<String, Object> source = response.getSource();
System.out.println(source);
}
查询多个文档
和之前索引映射不同。查询多个文档的时候，我们需要将查询参数放入的请求体的JSON中。下面是进行多文档查询JSON的多个写法之一。
http请求
GET localhost:9200/test_city_info/_mget
请求头
HEAD Content-Type:application/json
请求参数
{
"docs": [
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1"
},
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "6MEczm0BIQZGGtiybqNs"
}
]
}
响应内容
{
"docs": [
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 1,
"_seq_no": 0,
"_primary_term": 3,
"found": true,
"_source": {
"name": "北京",
"population": "特大城市",
"desc": "首都",
"gdp": "万亿级",
"province": "北京",
"college": "清华、北大",
"celebrity": "老舍"
}
},
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "6MEczm0BIQZGGtiybqNs",
"_version": 1,
"_seq_no": 1,
"_primary_term": 3,
"found": true,
"_source": {
"name": "上海",
"population": "特大城市",
"desc": "经济中心、大城市",
"gdp": "万亿级",
"province": "上海",
"college": "复旦大学",
"celebrity": "黄炎培"
}
}
]
}
多文档请求JAVA代码
多文档请求JAVA代码中使用了MultiGetRequest对象，后续我们操作的时候会接触到很多Multi*****相关的请求对象，ES中多请求操作的对象都是以此为前缀
public static void queryMultiDoc() throws IOException {
MultiGetRequest multiGetRequest = new MultiGetRequest();
MultiGetRequest.Item item1 = new MultiGetRequest.Item(
"test_city_info", //索引名称
"1");
MultiGetRequest.Item item2 = new MultiGetRequest.Item(
"test_city_info", //索引名称
"6MEczm0BIQZGGtiybqNs");
multiGetRequest.add(item1);
multiGetRequest.add(item2);
MultiGetResponse mget = getClient().mget(multiGetRequest, RequestOptions.DEFAULT);
MultiGetItemResponse[] responses = mget.getResponses();
for (int i = 0; i < responses.length; i++) {
MultiGetItemResponse rest = responses[i];
Map<String, Object> source = rest.getResponse().getSource();
System.out.println(source);
}
}
修改文档
针对更新数据es提供了多种可能，除了传统的全量还提供了了部分字段更新，或者在更新操作中嵌套某些逻辑
http请求
POST localhost:9200/test_city_info/_update/1
请求头
HEAD Content-Type:application/json
请求参数
{
"doc": {
"name": "北京",
"population": "特大城市",
"desc": "首都、特大城市",
"gdp": "万亿级",
"province": "北京",
"college": "清华、北大",
"celebrity": "老舍"
}
}
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 2,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 2,
"_primary_term": 3
}
java
public static void updateDoc() throws IOException {
Map<String, Object> jsonMap = new HashMap<>();
jsonMap.put("name", "北京");
jsonMap.put("population", "特大城市");
jsonMap.put("desc", "首都");
jsonMap.put("gdp", "万亿级");
jsonMap.put("province", "北京");
jsonMap.put("college", "清华、北大");
jsonMap.put("celebrity", "老舍");
UpdateRequest request = new UpdateRequest("test_city_info", "1")
.doc(jsonMap); //作为Map提供的部分文档源会自动转换为JSON格式
}
修改文档中某个字段
使用脚本我们可以更新某个数据部分内容。
http请求
POST localhost:9200/test_city_info/_update/1
请求头
HEAD Content-Type:application/json
请求参数
{
"script": "ctx._source.remove(\"desc\")"
}
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 3,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 3,
"_primary_term": 3
}
查询后内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 3,
"_seq_no": 3,
"_primary_term": 3,
"found": true,
"_source": {
"name": "北京",
"population": "特大城市",
"gdp": "万亿级",
"province": "北京",
"college": "清华、北大",
"celebrity": "老舍"
}
}
在请求值的赋值动作上，我们不需要直接赋上最终结果，可以将其结果使用请求体中的某些参数的值
http请求
POST localhost:9200/test_city_info/_update/1
HEAD Content-Type:application/json
参数
{
"script": {
"source": "ctx._source.desc = params.desc",
"params": {
"desc": "新的描述"
}
}
}
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 5,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 5,
"_primary_term": 3
}
查询后内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 5,
"_seq_no": 5,
"_primary_term": 3,
"found": true,
"_source": {
"name": "北京",
"population": "特大城市",
"gdp": "万亿级",
"province": "北京",
"college": "清华、北大",
"celebrity": "老舍",
"desc": "新的描述"
}
}
删除文档
删除文档内容比较简单，使用DELETE方法，将之前创建请求就可以修改为删除请求
http请求
localhost:9200/test_city_info/_doc/1
响应内容
{
"_index": "test_city_info",
"_type": "_doc",
"_id": "1",
"_version": 7,
"result": "deleted",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 7,
"_primary_term": 3
}
删除文档JAVA逻辑
public static void deleteDoc() throws IOException {
DeleteRequest request = new DeleteRequest(
"test_city_info", //索引
"6MEczm0BIQZGGtiybqNs"); //文档id
DeleteResponse delete = getClient().delete(request, RequestOptions.DEFAULT);
}