Elastisearch是一个很强大,易用的搜索引擎
在系统上运行Elastisearch只需以下几步
1.下载Elastisearch
复制代码 代码如下:
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-5.4.0.zip
2.解压
unzip elasticsearch-5.4.0.zip
3.运行
elasticsearch-5.4.0/bin/elasticsearch
这时有可能会直接被Killed掉，因为内存溢出（OOM），elastisearch占用的内存非常大，所以在内存比较小的服务器上运行要先修改jvm的内存大小
vi elasticsearch-5.4.0/config/jvm.options
将22和23行的栈堆大小改为512M
-Xms512M -Xmx512M
如果重新启动后还是killed就再改小一点
4.测试是否成功
curl 'http://localhost:9200/?pretty'
你能看到以下返回信息:
{
"status": 200,
"name": "Shrunken Bones",
"version": {
"number": "1.4.0",
"lucene_version": "4.10"
},
"tagline": "You Know, for Search"
}
则表明启动成功
接下来我们用Java的API来操作Elasticsearch
首先是导入elastisearch和log4j的包
POM
4.0.0 com.jk ElasticsearchExample1.0-SNAPSHOT org.elasticsearch.client transport5.4.0 org.apache.logging.log4j log4j-api2.7
以下是常用的几种操作
1.创建client
Client client = null;
try {
client = new PreBuiltTransportClient(Settings.EMPTY)
.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
} catch (Exception e) {
e.printStackTrace();
}
2.创建索引
private static void recreateIndex(Client client) {
if (client.admin().indices().prepareExists(index).execute().actionGet()
.isExists()) {
DeleteIndexResponse deleteIndexResponse = client.admin().indices()
.delete(new DeleteIndexRequest(index)).actionGet();
System.out.println("delete index :");
System.out.println(deleteIndexResponse);
}
CreateIndexResponse createIndexResponse = client.admin().indices()
.prepareCreate(index).execute().actionGet();
System.out.println("create index :");
System.out.println(createIndexResponse);
}
3.插入数据
@SuppressWarnings({"rawtypes", "unchecked"})
private static void doIndex(final Client client) {
Map s11 = new linkedHashMap();
s11.put("title", "Think in java");
s11.put("origin", "美国");
s11.put("description", "初级java开发人员必读的书");
s11.put("author", "Bruce Eckel");
s11.put("price", 108);
Map s12 = new linkedHashMap();
s12.put("title", "Head First Java");
s12.put("origin", "英国");
s12.put("description", "java入门教材");
s12.put("author", "Kathy Sierra");
s12.put("price", 54);
Map s21 = new linkedHashMap();
s21.put("title", "Design Pattern");
s21.put("origin", "法国");
s21.put("description", "程序员不得不读的设计模式");
s21.put("author", "Kathy Sierra");
s21.put("price", 89);
Map s22 = new linkedHashMap();
s22.put("title", "黑客与画家");
s22.put("origin", "法国");
s22.put("description", "读完之后脑洞大开");
s22.put("author", "Paul Graham");
s22.put("price", 35);
BulkResponse bulkResponse = client
.prepareBulk()
.add(client.prepareIndex(index, type).setId("11").setSource(s11).setOpType(IndexRequest.OpType.INDEX).request())
.add(client.prepareIndex(index, type).setId("12").setSource(s12).setOpType(IndexRequest.OpType.INDEX).request())
.add(client.prepareIndex(index, type).setId("21").setSource(s21).setOpType(IndexRequest.OpType.INDEX).request())
.add(client.prepareIndex(index, type).setId("22").setSource(s22).setOpType(IndexRequest.OpType.INDEX).request())
.execute().actionGet();
if (bulkResponse.hasFailures()) {
System.err.println("index docs ERROR:" + bulkResponse.buildFailureMessage());
} else {
System.out.println("index docs SUCCESS:");
System.out.println(bulkResponse);
}
}
4.查询所有
private static void searchAll(Client client) {
SearchResponse response = client.prepareSearch(index)
.setQuery(QueryBuilders.matchAllQuery())
.setExplain(true).execute().actionGet();
System.out.println("searchAll : ");
for (SearchHit searchHit : response.getHits()) {
System.out.println("********");
System.out.println(searchHit.getSource());
}
}
5.关键词查询
private static void searchKeyWord(Client client) {
SearchResponse response = client.prepareSearch(index)
//查询所有字段匹配关键字
.setQuery(QueryBuilders.matchQuery("_all", "法国"))
//设置最小匹配程度
// .setQuery(QueryBuilders.matchQuery("_all", "法国").minimumShouldMatch("100%"))
.execute().actionGet();
System.out.println("searchKeyWord : ");
System.out.println(response);
}
6.数值范围过滤
private static void searchRange(Client client) {
SearchResponse response = client.prepareSearch(index).
//大于80，小于100
setQuery(QueryBuilders.rangeQuery("price").gt(80).lt(100))
.execute()
.actionGet();
System.out.println("searchRange : ");
System.out.println(response);
}
7.排序
private static void searchOrdered(Client client) {
SearchResponse response = client.prepareSearch(index)
.setQuery(QueryBuilders.matchAllQuery())
//根据价格降序排序
.addSort(SortBuilders.fieldSort("price")
.order(SortOrder.DESC)).execute().actionGet();
System.out.println("searchOrdered : ");
System.out.println(response);
}
8.高亮关键字
private static void searchHightlight(Client client) {
//高亮多个字段
HighlightBuilder highlightBuilder = new HighlightBuilder();
highlightBuilder.field("title");
highlightBuilder.field("description");
SearchResponse response = client.prepareSearch(index)
//单条件匹配，高亮时只能高亮该字段
// .setQuery(QueryBuilders.matchQuery("title", "java"))
//多条件匹配，高亮时只能高亮多个字段
.setQuery(QueryBuilders.multiMatchQuery("开发人员必读", "title", "description"))
.highlighter(highlightBuilder)
.execute()
.actionGet();
System.out.println("searchHightlight : ");
System.out.println(response);
}
9.根据id查找
private static void findById(final Client client) {
String id="12";
GetResponse response = client.prepareGet(index, type, id).get();
System.out.println("findById");
System.out.println(response);
}
10.删除
private static void deleteById(Client client) {
String id="12";
DeleteResponse response = client.prepareDelete(index, type, id).get();
}
11.更新
private static void updateById(Client client) {
try {
String id="11";
client.prepareUpdate(index, type, id)
.setDoc(jsonBuilder()
.startObject()
.field("title", "白鹿原")
.endObject())
.get();
} catch (IOException e) {
e.printStackTrace();
}
}
常用的操作就这些,代码上传到https://github.com/jkgeekJack/ElasticsearchExample
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。
