Elasticsearch 之（25）重写IK分词器源码来基于mysql热更新词库
热更新
在上一节《IK分词器配置文件讲解以及自定义词库》自定义词库，每次都是在es的扩展词典中，手动添加新词语，很坑（1）每次添加完，都要重启es才能生效，非常麻烦
（2）es是分布式的，可能有数百个节点，你不能每次都一个一个节点上面去修改
es不停机，直接我们在外部某个地方添加新的词语，es中立即热加载到这些新词语
热更新的方案
（1）修改ik分词器源码，然后手动支持从mysql中每隔一定时间，自动加载新的词库（2）基于ik分词器原生支持的热更新方案，部署一个web服务器，提供一个http接口，通过modified和tag两个http响应头，来提供词语的热更新
用第一种方案，第二种，ik git社区官方都不建议采用，觉得不太稳定
1、下载源码
https://github.com/medcl/elasticsearch-analysis-ik/tree/v5.2.0
ik分词器，是个标准的java maven工程，直接导入eclipse就可以看到源码
2、修改源码
Dictionary单例类的初始化方法initial，在这里需要创建一个我们自定义的线程，并且启动它
/**
* 词典初始化 由于IK Analyzer的词典采用Dictionary类的静态方法进行词典初始化
* 只有当Dictionary类被实际调用时，才会开始载入词典， 这将延长首次分词操作的时间 该方法提供了一个在应用加载阶段就初始化字典的手段
*
* @return Dictionary
*/
public static synchronized Dictionary initial(Configuration cfg) {
if (singleton == null) {
synchronized (Dictionary.class) {
if (singleton == null) {
singleton = new Dictionary(cfg);
singleton.loadMainDict();
singleton.loadSurnameDict();
singleton.loadQuantifierDict();
singleton.loadSuffixDict();
singleton.loadPrepDict();
singleton.loadStopWordDict();
new Thread(new HotDictReloadThread()).start();
if(cfg.isEnableRemoteDict()){
// 建立监控线程
for (String location : singleton.getRemoteExtDictionarys()) {
// 10 秒是初始延迟可以修改的 60是间隔时间 单位秒
pool.scheduleAtFixedRate(new Monitor(location), 10, 60, TimeUnit.SECONDS);
}
for (String location : singleton.getRemoteExtStopWordDictionarys()) {
pool.scheduleAtFixedRate(new Monitor(location), 10, 60, TimeUnit.SECONDS);
}
}
return singleton;
}
}
}
return singleton;
}HotDictReloadThread类：就是死循环，不断调用Dictionary.getSingleton().reLoadMainDict()，去重新加载词典public class HotDictReloadThread implements Runnable {
private static final Logger logger = ESLoggerFactory.getLogger(HotDictReloadThread.class.getName());
@Override
public void run() {
while(true) {
logger.info("[==========]reload hot dict from mysql......");
Dictionary.getSingleton().reLoadMainDict();
}
}
}Dictionary类：更新词典 this.loadMySQLExtDict()/**
* 加载主词典及扩展词典
*/
private void loadMainDict() {
// 建立一个主词典实例
_MainDict = new DictSegment((char) 0);
// 读取主词典文件
Path file = PathUtils.get(getDictRoot(), Dictionary.PATH_DIC_MAIN);
InputStream is = null;
try {
is = new FileInputStream(file.toFile());
} catch (FileNotFoundException e) {
logger.error(e.getMessage(), e);
}
try {
BufferedReader br = new BufferedReader(new InputStreamReader(is, "UTF-8"), 512);
String theWord = null;
do {
theWord = br.readLine();
if (theWord != null && !"".equals(theWord.trim())) {
_MainDict.fillSegment(theWord.trim().toCharArray());
}
} while (theWord != null);
} catch (IOException e) {
logger.error("ik-analyzer", e);
} finally {
try {
if (is != null) {
is.close();
is = null;
}
} catch (IOException e) {
logger.error("ik-analyzer", e);
}
}
// 加载扩展词典
this.loadExtDict();
// 加载远程自定义词库
this.loadRemoteExtDict();
// 从mysql加载词典
this.loadMySQLExtDict();
}
/**
* 从mysql加载热更新词典
*/
private void loadMySQLExtDict() {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Path file = PathUtils.get(getDictRoot(), "jdbc-reload.properties");
prop.load(new FileInputStream(file.toFile()));
logger.info("[==========]jdbc-reload.properties");
for(Object key : prop.keySet()) {
logger.info("[==========]" + key + "=" + prop.getProperty(String.valueOf(key)));
}
logger.info("[==========]query hot dict from mysql, " + prop.getProperty("jdbc.reload.sql") + "......");
conn = DriverManager.getConnection(
prop.getProperty("jdbc.url"),
prop.getProperty("jdbc.user"),
prop.getProperty("jdbc.password"));
stmt = conn.createStatement();
rs = stmt.executeQuery(prop.getProperty("jdbc.reload.sql"));
while(rs.next()) {
String theWord = rs.getString("word");
logger.info("[==========]hot word from mysql: " + theWord);
_MainDict.fillSegment(theWord.trim().toCharArray());
}
Thread.sleep(Integer.valueOf(String.valueOf(prop.get("jdbc.reload.interval"))));
} catch (Exception e) {
logger.error("erorr", e);
} finally {
if(rs != null) {
try {
rs.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
if(stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
if(conn != null) {
try {
conn.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
}
}Dictionary类：更新分词 this.loadMySQLStopwordDict();
/**
* 从mysql加载停用词
*/
private void loadMySQLStopwordDict() {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Path file = PathUtils.get(getDictRoot(), "jdbc-reload.properties");
prop.load(new FileInputStream(file.toFile()));
logger.info("[==========]jdbc-reload.properties");
for(Object key : prop.keySet()) {
logger.info("[==========]" + key + "=" + prop.getProperty(String.valueOf(key)));
}
logger.info("[==========]query hot stopword dict from mysql, " + prop.getProperty("jdbc.reload.stopword.sql") + "......");
conn = DriverManager.getConnection(
prop.getProperty("jdbc.url"),
prop.getProperty("jdbc.user"),
prop.getProperty("jdbc.password"));
stmt = conn.createStatement();
rs = stmt.executeQuery(prop.getProperty("jdbc.reload.stopword.sql"));
while(rs.next()) {
String theWord = rs.getString("word");
logger.info("[==========]hot stopword from mysql: " + theWord);
_StopWords.fillSegment(theWord.trim().toCharArray());
}
Thread.sleep(Integer.valueOf(String.valueOf(prop.get("jdbc.reload.interval"))));
} catch (Exception e) {
logger.error("erorr", e);
} finally {
if(rs != null) {
try {
rs.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
if(stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
if(conn != null) {
try {
conn.close();
} catch (SQLException e) {
logger.error("error", e);
}
}
}
}配置jdbc.url=jdbc:mysql://localhost:3306/test?serverTimezone=GMT jdbc.user=root jdbc.password=root jdbc.reload.sql=select word from hot_words jdbc.reload.stopword.sql=select stopword as word from hot_stopwords jdbc.reload.interval=1000
3、mvn package打包代码
target\releases\elasticsearch-analysis-ik-5.2.0.zip
4、解压缩ik压缩包
将mysql驱动jar，放入ik的目录下
5、重启es
6、在mysql中添加词库与停用词
7、kibana分词验证
GET /my_index/_analyze
{
"text": "一人饮酒醉",
"analyzer": "ik_max_word"
}
{
"tokens": [
{
"token": "一人饮酒醉",
"start_offset": 0,
"end_offset": 5,
"type": "CN_WORD",
"position": 0
},
{
"token": "一人",
"start_offset": 0,
"end_offset": 2,
"type": "CN_WORD",
"position": 1
},
{
"token": "一",
"start_offset": 0,
"end_offset": 1,
"type": "TYPE_CNUM",
"position": 2
},
{
"token": "人",
"start_offset": 1,
"end_offset": 2,
"type": "COUNT",
"position": 3
},
{
"token": "饮酒",
"start_offset": 2,
"end_offset": 4,
"type": "CN_WORD",
"position": 4
},
{
"token": "饮",
"start_offset": 2,
"end_offset": 3,
"type": "CN_WORD",
"position": 5
},
{
"token": "酒醉",
"start_offset": 3,
"end_offset": 5,
"type": "CN_WORD",
"position": 6
},
{
"token": "酒",
"start_offset": 3,
"end_offset": 4,
"type": "CN_WORD",
"position": 7
},
{
"token": "醉",
"start_offset": 4,
"end_offset": 5,
"type": "CN_WORD",
"position": 8
}
]
}
