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ElasticSearch第四篇 Mapping

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yangyp8110 edited this page Jan 17, 2018 · 2 revisions

Mapping

1.数据类型声明

它类似于静态语言中的数据类型声明，比如声明一个字段为String， 以后这个变量都只能存储String类型的数据。同样的， 一个number类型的 mapping 字段只能存储number类型的数据。

2.Mapping它定义了 Type 的属性。

eg : "_ttl": {"enabled": false｝ 示 ttl关闭，ttl默认就是关闭。

3.指定分词器。

    "id": {
        "index": "not_analyzed",
        "type": "string"
    }

指定字段 id不分词，并且类型为 string。

创建Mapping

http方式创建Maping：

新增Mapping

  • 首先创建一个索引
[root@yyp ~]# curl -XPUT http://192.168.74.129:9200/productindex
{"acknowledged":true,"shards_acknowledged":true}[root@yyp ~]#
  • 没有设置mapping，查看下mapping：
[root@yyp ~]# curl -XGET http://192.168.74.129:9200/productindex/_mapping?pretty

返回结果：

{
  "productindex" : {
    "mappings" : { }
  }
}

从查询的结果可以看到mapping为空 *给productindex这个索引加一个type，type name为product，并设置mapping：

curl -XPOST http://192.168.74.129:9200/productindex/product/_mapping?pretty -d ' 
{
    "product": {
            "properties": {
                "title": {
                    "type": "string",
                    "store": "yes"
                },
                "description": {
                    "type": "string",
                    "index": "not_analyzed"
                },
                "price": {
                    "type": "double"
                },
                "onSale": {
                    "type": "boolean"
                },
                "type": {
                    "type": "integer"
                },
                "createDate": {
                    "type": "date"
                }
            }
        }
  }
'

返回结果：

{
  "acknowledged" : true
}

给productindex加了一个type，并写入了product的mapping信息，查看是否增加成功：

[root@yyp ~]# curl -XGET http://192.168.74.129:9200/productindex/_mapping?pretty

返回结果：

{
  "productindex" : {
    "mappings" : {
      "product" : {
        "properties" : {
          "createDate" : {
            "type" : "date"
          },
          "description" : {
            "type" : "keyword"
          },
          "onSale" : {
            "type" : "boolean"
          },
          "price" : {
            "type" : "double"
          },
          "title" : {
            "type" : "text",
            "store" : true
          },
          "type" : {
            "type" : "integer"
          }
        }
      }
    }
  }
}

修改Mapping

  • 如果想给product新增一个字段，那么需要修改mapping
[root@yyp ~]# curl -XPOST http://192.168.74.129:9200/productindex/product/_mapping?pretty -d '{
     "product": {
                "properties": {
                     "amount":{
                        "type":"integer"
                   }
                }
            }
    }'

返回：

{
  "acknowledged" : true
}
  • 如果要修改一个字段的类型呢，比如onSale字段的类型为boolean，现在想要修改为string类型
[root@yyp ~]# curl -XPOST http://192.168.74.129:9200/productindex/product/_mapping?pretty -d '{
     "product": {
                "properties": {
                 "onSale":{
                    "type":"string" 
               }
            }
        }
}'

返回：

{
  "error" : {
    "root_cause" : [
      {
        "type" : "illegal_argument_exception",
        "reason" : "mapper [onSale] of different type, current_type [boolean], merged_type [text]"
      }
    ],
    "type" : "illegal_argument_exception",
    "reason" : "mapper [onSale] of different type, current_type [boolean], merged_type [text]"
  },
  "status" : 400
}

为什么不能修改一个字段的type？原因是一个字段的类型修改以后，那么该字段的所有数据都需要重新索引。Elasticsearch底层使用的是lucene库，字段类型修改以后索引和搜索要涉及分词方式等操作，不允许修改类型在我看来是符合lucene机制的。

java创建Mapping：

通过Elasticsearch-head(http://192.168.74.129:9100/ )查出存在Elasticsearch内的内容：

按照官网配置，报错如下：

java.lang.ClassNotFoundException: org.elasticsearch.plugins.ActionPlugin
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_101]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_101]
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_101]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_101]
	at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_101]

感谢来自StackOverFlow的解决方案。新增了elasticsearch的依赖

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>5.0.1</version>
        </dependency>

输出查询结果：

2017-02-26 21:09:21.040  INFO 8508 --- [nio-8080-exec-1] c.es.search.controller.SearchController  : res:{"_index":"index","_type":"fulltext","_id":"3","_version":1,"found":true,"_source":
{"content":"中韩渔警冲突调查：韩警平均每天扣1艘中国渔船"}
}，getSourceAsString：
{"content":"中韩渔警冲突调查：韩警平均每天扣1艘中国渔船"}
,index:index

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.es.search.demo</groupId>
    <artifactId>es.search.demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!-- Inherit defaults from Spring Boot -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.0.RELEASE</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <!-- Add typical dependencies for a web application -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>5.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>5.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.7</version>
        </dependency>
    </dependencies>

    <!-- Package as an executable jar -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

项目示例地址：es.search.demo

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