ElasticSearch 6.8.1动态更新同义词（适配elasticsearch-analysis-dynamic-synonym）

动态更新同义词插件适配

非热更新的同义词配置
elasticsearch-analysis-dynamic-synonym 插件可以动态更新同义词，但github上只有5.1.1的版本了，不适配es6.8.1，通过修改源码适配6.8.1。
首先从github上下载5.1.1的源码和插件压缩包
github地址

下载后解压源码包，并导入idea
POM文件修改
修改如下两个版本号

源码修改
由于修改了导入的elasticsearch版本，源码有些地方会报错，修改DynamicSynonymFilter下的getLogger，并同时修改其它类里的getLogger报错的地方：

// public static Logger logger = ESLoggerFactory.getLogger("dynamic-synonym");// 6.8.1的es去掉了ELLoggerFactory，修改为Loggerspublic static Logger logger = Loggers.getLogger(String.class,"dynamic-synonym");

修改LocalSynonymFile下的getReader，新增一个newBufferedReader方法（6.8.1没有这个方法，从5.1.1的源码里把newBufferedReader方法给copy出来）

/*** Opens the given url for reading returning a {@code BufferedReader} that may be* used to read text from the URL in an efficient manner. Bytes from the* file are decoded into characters using the specified charset.*/// copy from elasticsearch-5.1.1.jar source codepublic static BufferedReader newBufferedReader(URL url, Charset cs) throws IOException {CharsetDecoder decoder = cs.newDecoder();Reader reader = new InputStreamReader(url.openStream(), decoder);return new BufferedReader(reader);}public Reader getReader() {Reader reader = null;BufferedReader br = null;try {reader = newBufferedReader(synonymFilePath.toUri().toURL(), Charsets.UTF_8);/*br = new BufferedReader(new InputStreamReader(synonymFileURL.openStream(), Charsets.UTF_8));StringBuffer sb = new StringBuffer("");String line = null;while ((line = br.readLine()) != null) {logger.info("reload local synonym: {}", line);sb.append(line).append(System.getProperty("line.separator"));}reader = new FastStringReader(sb.toString());*/} catch (IOException e) {logger.error("get local synonym reader {} error!", e, location);throw new IllegalArgumentException("IOException while reading local synonyms file", e);} finally {try {if (br != null) {br.close();}} catch (IOException e) {e.printStackTrace();}}return reader;}

修改DynamicSynonymPlugin里的createComponents，这个方法是从第三方的适配6.6.2的jar包里找到的，放进来也能用

 /* @Overridepublic Collection<Object> createComponents(Client client,ClusterService clusterService,ThreadPool threadPool,ResourceWatcherService resourceWatcherService,ScriptService scriptService,SearchRequestParsers searchRequestParsers) {Collection<Object> components = new ArrayList<>();components.add(pluginComponent);return components;}*/// copy from es-as-dy-syn-6.62 of third partypublic Collection<Object> createComponents(Client client,ClusterService clusterService,ThreadPool threadPool,ResourceWatcherService resourceWatcherService,ScriptService scriptService,NamedXContentRegistry xContentRegistry,Environment environment,NodeEnvironment nodeEnvironment,NamedWriteableRegistry namedWriteableRegistry) {Collection<Object> components = new ArrayList();components.add(this.pluginComponent);return components;}

总之就是有报错的就去解决掉，一般报错的都是6.8.1的es的jar包里少了啥，从5.1.1的es里的jar包里把它找过来就行了

打包解压到es服务器

maven install打成jar包，放进从github上下载的插件包解压出来的文件夹（替换掉5.1.1的插件jar包），并修改其中的properties文件（这个文件应该会被es服务器读取，修改版本号，注释掉jvm\site\isolate否则会报错）

# Elasticsearch plugin descriptor file
# This file must exist as 'plugin-descriptor.properties' at
# the root directory of all plugins.
#
# A plugin can be 'site', 'jvm', or both.
#
### example site plugin for "foo":
#
# foo.zip <-- zip file for the plugin, with this structure:
#   _site/ <-- the contents that will be served
#   plugin-descriptor.properties <-- example contents below:
#
# site=true
# description=My cool plugin
# version=1.0
#
### example jvm plugin for "foo"
#
# foo.zip <-- zip file for the plugin, with this structure:
#   <arbitrary name1>.jar <-- classes, resources, dependencies
#   <arbitrary nameN>.jar <-- any number of jars
#   plugin-descriptor.properties <-- example contents below:
#
# jvm=true
# classname=foo.bar.BazPlugin
# description=My cool plugin
# version=2.0.0-rc1
# elasticsearch.version=2.0
# java.version=1.7
#
### mandatory elements for all plugins:
#
# 'description': simple summary of the plugin
description=Analysis-plugin for synonym
#
# 'version': plugin's version
version=6.8.1
#
# 'name': the plugin name
name=analysis-dynamic-synonym### mandatory elements for site plugins:
#
# 'site': set to true to indicate contents of the _site/
#  directory in the root of the plugin should be served.
#site=${elasticsearch.plugin.site}
#
### mandatory elements for jvm plugins :
#
# 'jvm': true if the 'classname' class should be loaded
#  from jar files in the root directory of the plugin.
#  Note that only jar files in the root directory are
#  added to the classpath for the plugin! If you need
#  other resources, package them into a resources jar.
#jvm=true
#
# 'classname': the name of the class to load, fully-qualified.
classname=com.bellszhu.elasticsearch.plugin.DynamicSynonymPlugin
#
# 'java.version' version of java the code is built against
# use the system property java.specification.version
# version string must be a sequence of nonnegative decimal integers
# separated by "."'s and may have leading zeros
java.version=1.8
#
# 'elasticsearch.version' version of elasticsearch compiled against
# You will have to release a new version of the plugin for each new
# elasticsearch release. This version is checked when the plugin
# is loaded so Elasticsearch will refuse to start in the presence of
# plugins with the incorrect elasticsearch.version.
elasticsearch.version=6.8.1
#
### deprecated elements for jvm plugins :
#
# 'isolated': true if the plugin should have its own classloader.
# passing false is deprecated, and only intended to support plugins
# that have hard dependencies against each other. If this is
# not specified, then the plugin is isolated by default.
#isolated=${elasticsearch.plugin.isolated}
#

打包上传至服务器es目录下的plugins目录下新建的dynamic-synonym目录下解压，重启es服务器即可加载插件成功
修改es服务器的java.policy文件
如果需要远程获取同义词文件，则需要修改这个文件，否则会由于java的什么安全机制，在获取文件时报错
找到jre/lib/security 下的java.policy文件

grant中添加一行
permission java.net.SocketPermission “*”, “connect,resolve”;

之后就是和github上的步骤一样就可以了。
还有一些要注意的地方：
官方示例中的这个需要改成ik_smart或者ik_max_word（whitespace是按空格分词的）

synonym就是自定义的分析器，在建立mapping时使用这个自定义分析器

同义词文件格式：

A=>B
C=>D
即B是A的同义词，D是C的同义词（好像是单向联想的）
A,B
C,D
即AB CD互为同义词（双向联想）
建议用2，因为1实测有bug如
A=>B
B=>C
但实际搜索时 A只能搜出A，搜不出B,C；B能搜出B,C，C也能搜出B,C