记druid 在配置中心下的一个大坑： cpu 达到 100%

把我们的dubbo 应用移步到配置中心上去之后，发现我们的应用过一段时间就会出现cpu 100%的情况 （大概是12个小时），一开始cpu占用是2-5% 的样子，什么都没做，后面竟然用尽了cpu。。

把jvm 线程堆栈打印一下，发现线程数竟然达到了上万.....   发现最多是这样的一个线程：

"com.alibaba.nacos.client.Worker.fixed-192.168.11.196_8848-1f3c60b6-3e28-44eb-9798-7f7eeeff6a8d" #138 daemon prio=5 os_prio=0 tid=0x0000000026c49000 nid=0xf60 waiting on condition [0x000000002aebe000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x000000079c3a15a8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

我们的配置中心是nacos，从com.alibaba.nacos.client.Worker.fixed来看， 跟nacos 好像有点关系。事实也是如此，我们之前的没有用nacos ， 是根本没有这个问题的。 但是，也不是每个应用都是这样， 我们的网关应用就没这个问题。。

spring-cloud-alibaba-dependencies 刚刚从0.2.1.RELEASE 升级到了 0.2.2.RELEASE， 难道这个有关系？ 和 spring-cloud-dependencies 的兼容性问题？和 spring-cloud-starter的兼容性问题？

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Finchley.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>0.2..RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter</artifactId>
                <version>2.0..RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

但退回原来的版本，问题依旧。

重新写了一个spring boot 程序，没有问题。 把原来的那一套加上，问题出现了。 观察发现数据源似乎有问题。

怀疑是nacos 的坑。com.alibaba.nacos.client.Worker 是什么鬼？ 全局搜索类名， 没发现，难道不是一个类吗？ fixed 是一个方法吗？ 找不到。 如是把nacos 1.0.0 的源码下载了下来。 全局搜索类com.alibaba.nacos.client.Worker， 还是没发现。全局全文搜索fixed ,发现了com/alibaba/nacos/client/config/impl/ServerListManager.java。通过本机调试，发现了 com.alibaba.nacos.client.config.impl.ClientWorker， 同时发现了com.alibaba.nacos.client.Worker 字眼 , 原来是写死的！ 依然不清楚问题原因。

直觉告诉我 正是 ClientWorker 不断创建了我们的 “问题线程”， 但是其机制我并不太清楚。贸然的调试没有发现根本原因，反而把我弄得一头雾水。 我得看一下源码。

不断的加断点， 发现了 com.alibaba.nacos.client.config.impl.CacheData 的 safeNotifyListener 方法， 其中的 listener.receiveConfigInfo 方法似乎出现了问题， 执行到了1的地方，2却不会执行，真是奇了怪了， 难道陷入了死循环？

private void safeNotifyListener(final String dataId, final String group, final String content, final String md5, final ManagerListenerWrap listenerWrap) {
        final Listener listener = listenerWrap.listener;
        Runnable job = new Runnable() {
            public void run() {
                ClassLoader myClassLoader = Thread.currentThread().getContextClassLoader();
                ClassLoader appClassLoader = listener.getClass().getClassLoader();

                try {
                    if (listener instanceof AbstractSharedListener) {
                        AbstractSharedListener adapter = (AbstractSharedListener)listener;
                        adapter.fillContext(dataId, group);
                        CacheData.LOGGER.info("[{}] [notify-context] dataId={}, group={}, md5={}", new Object[]{CacheData.this.name, dataId, group, md5});
                    }

                    Thread.currentThread().setContextClassLoader(appClassLoader);
                    ConfigResponse cr = new ConfigResponse();
                    cr.setDataId(dataId);
                    cr.setGroup(group);
                    cr.setContent(content);
                    CacheData.this.configFilterChainManager.doFilter((IConfigRequest)null, cr);
                    String contentTmp = cr.getContent();
                    listener.receiveConfigInfo(contentTmp); //1 出错！
                    listenerWrap.lastCallMd5 = md5; // 2
                    CacheData.LOGGER.info("[{}] [notify-ok] dataId={}, group={}, md5={}, listener={} ", new Object[]{CacheData.this.name, dataId, group, md5, listener});
                } catch (NacosException var9) {
                    CacheData.LOGGER.error("[{}] [notify-error] dataId={}, group={}, md5={}, listener={} errCode={} errMsg={}", new Object[]{CacheData.this.name, dataId, group, md5, listener, var9.getErrCode(), var9.getErrMsg()});
                } catch (Throwable var10) { //3 异常到了这里来， 但是这个异常并没有打印出来！！
                    CacheData.LOGGER.error("[{}] [notify-error] dataId={}, group={}, md5={}, listener={} tx={}", new Object[]{CacheData.this.name, dataId, group, md5, listener, var10.getCause()});
                } finally { // 4
                    Thread.currentThread().setContextClassLoader(myClassLoader);
                }

            }
        };
        long startNotify = System.currentTimeMillis();

        try {
            if (null != listener.getExecutor()) {
                listener.getExecutor().execute(job);
            } else {
                job.run();
            }
        } catch (Throwable var12) {
            LOGGER.error("[{}] [notify-error] dataId={}, group={}, md5={}, listener={} throwable={}", new Object[]{this.name, dataId, group, md5, listener, var12.getCause()});
        }

        long finishNotify = System.currentTimeMillis();
        LOGGER.info("[{}] [notify-listener] time cost={}ms in ClientWorker, dataId={}, group={}, md5={}, listener={} ", new Object[]{this.name, finishNotify - startNotify, dataId, group, md5, listener});
    }

结果发现并不是的，原因在于 我没有在3 和 4的 地方打断点， 所以误以为是 死循环。 其实1 的地方有报错， 直接跳到了3， 所以2没有执行。 加断点给3 和 4 就发现了问题原因！listener.receiveConfigInfo 是一个接口， 其实现不确定， F7 跳入发现 实际是 com.alibaba.nacos.api.config.listener.Listener#receiveConfigInfo 方法，跟进去， 发现执行到NacosContextRefresher.this.applicationContext.publishEvent(new RefreshEvent(this, (Object)null, "Refresh Nacos config")); 的时候， 下一行似乎没有执行。。 可是publishEvent 方法怎么跟进去，这就太麻烦了。。

从3 处， 我知道了问题的cause：

Error creating bean with name 'writeDataSource': Could not bind properties to 'DruidDataSource' : prefix=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true

t = {ConfigurationPropertiesBindException@} "org.springframework.boot.context.properties.ConfigurationPropertiesBindException: Error creating bean with name 'writeDataSource': Could not bind properties to 'DruidDataSource' : prefix=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'spring.datasource.write' to com.alibaba.druid.pool.DruidDataSource"
 beanType = {Class@} "class com.alibaba.druid.pool.DruidDataSource"
 annotation = {$Proxy30@} "@org.springframework.boot.context.properties.ConfigurationProperties(prefix=spring.datasource.write, value=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true)"
 beanName = "writeDataSource"
 resourceDescription = null
 relatedCauses = null
 detailMessage = "Error creating bean with name 'writeDataSource': Could not bind properties to 'DruidDataSource' : prefix=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true"
 cause = {BindException@} "org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'spring.datasource.write' to com.alibaba.druid.pool.DruidDataSource"
  target = {Bindable@} "[Bindable@7edd0fc7 type = com.alibaba.druid.pool.DruidDataSource, value = 'provided', annotations = array<Annotation>[@org.springframework.boot.context.properties.ConfigurationProperties(prefix=spring.datasource.write, value=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true)]]"
  property = {ConfigurationProperty@} "[ConfigurationProperty@3794965c name = spring.datasource.write.url, value = '${MYSQL_WRITE_URL:jdbc:mysql://192.168.11.200:3418/elppmdb}?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&useSSL=false', origin = "spring.datasource.write.url" from property source "bootstrapProperties"]"
  name = {ConfigurationPropertyName@} "spring.datasource.write"
  detailMessage = "Failed to bind properties under 'spring.datasource.write' to com.alibaba.druid.pool.DruidDataSource"
  cause = {IllegalStateException@} "java.lang.IllegalStateException: Unable to set value for property url"
   detailMessage = "Unable to set value for property url"
   cause = {InvocationTargetException@} "java.lang.reflect.InvocationTargetException"
   stackTrace = {StackTraceElement[]@}
   suppressedExceptions = {Collections$UnmodifiableRandomAccessList@}  size =
  stackTrace = {StackTraceElement[]@}
  suppressedExceptions = {Collections$UnmodifiableRandomAccessList@}  size =
 stackTrace = {StackTraceElement[]@}
 suppressedExceptions = {Collections$UnmodifiableRandomAccessList@}  size =
CacheData.this.name = "fixed-192.168.11.196_8848-1f3c60b6-3e28-44eb-9798-7f7eeeff6a8d"

可以看到根本原因是：Unable to set value for property url ， 难道是 nacos 上的配置中心的配置有问题？

spring:
  application:
    name:  erdp_discuss_app
  profile:
    active: ${PROFILE_ACTIVE:local}
  cloud:
    nacos:
      discovery:
        server-addr: ${NACOS_SERVER_ADDR:192.168.11.196:}
  profiles:
    active: ${PROFILE_ACTIVE:local}
  jackson:
    time-zone: GMT+
    date-format: yyyy-MM-dd HH:mm:ss
    serialization:
      write_dates_as_timestamps: false

  datasource:
    write:
      url: jdbc:mysql://192.168.11.200:3418/elppmdb?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&useSSL=false
      username: elppm_user
      password: elppm
      driver-class-name: com.mysql.jdbc.Driver
      max-active:
      initial-size:
      min-idle:
      max-wait:
      time-between-eviction-runs-millis:
      min-evictable-idle-time-millis:
      validation-query: SELECT 'x' FROM DUAL
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
      filters: stat,wall,log4j
      # 通过connectProperties属性来打开mergeSql功能；慢SQL记录
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=
      # 合并多个DruidDataSource的监控数据
      #spring.datasource.useGlobalDataSourceStat=true
    read:
      url: ${MYSQL_READ_URL:jdbc:mysql://192.168.11.200:3418/elppmdb}?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&useSSL=false
      username: ${MYSQL_DB_USERNAME:elppm_user}
      password: ${MYSQL_DB_PASSWORD:elppm}
      driver-class-name: com.mysql.jdbc.Driver
      max-active:
      initial-size:
      min-idle:
      max-wait:
      time-between-eviction-runs-millis:
      min-evictable-idle-time-millis:
      validation-query: SELECT 'x' FROM DUAL
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
      filters: stat,wall,log4j
      # 通过connectProperties属性来打开mergeSql功能；慢SQL记录
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=
      # 合并多个DruidDataSource的监控数据
      #spring.datasource.useGlobalDataSourceStat=true

  redis:
    host: ${APP_REDIS_HOST:192.168.11.200}
    password: ${APP_REDIS_PW:Redis!} #password: # Login password of the redis server.
    port: ${APP_REDIS_PORT:}
    database:
    timeout:
    pool:
      max-active:  #最大连接数
      max-idle:  #最大空闲连接数
      max-wait: - #最大等待时间
      min-idle:  #初始化连接数
  http:
    multipart:
      enabled: true # Enable support of multi-part uploads.
      file-size-threshold: 4KB # Threshold after which files will be written to disk. Values can use the suffixed "MB" or "KB" to indicate a Megabyte or Kilobyte size.
      location: /tmp # Intermediate location of uploaded files.
      max-file-size: 5Mb # Max file size. Values can use the suffixed "MB" or "KB" to indicate a Megabyte or Kilobyte size.
      max-request-size: 50Mb # Max request size. Values can use the suffixed "MB" or "KB" to indicate a Megabyte or Kilobyte size.

  data:
    mongodb:
      uri: mongodb://${MONGODB_SERV_URL:192.168.11.200:27117/docs}

mybatis:
  typeAliasesPackage: com.lkk.ppm.discuss.domain
  configLocation: classpath:mybatis-config.xml
  mapperLocations: classpath:mybatis/*.xml

server:
  port: ${SERVER_PORT:8092}

erdpapp:
  basepath: ${RDP_BASE_PATH:/eRDPServer}
  logcharset: ${RDP_LOG_CHARSET:UTF-8}

可以看到，我们的配置是 数据源读写分离的， 并不是原始的那种。

我们的代码配置是：

package com.lkk.platform.common.service.datasource;

import com.alibaba.druid.pool.DruidDataSource;
import com.baomidou.mybatisplus.entity.GlobalConfiguration;
import com.baomidou.mybatisplus.enums.DBType;
import com.baomidou.mybatisplus.enums.IdType;
import com.baomidou.mybatisplus.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.spring.MybatisSqlSessionFactoryBean;
import com.lkk.platform.common.exception.SystemException;

import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.boot.autoconfigure.MybatisProperties;
import org.mybatis.spring.boot.autoconfigure.SpringBootVFS;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

import javax.sql.DataSource;

/**
 * 数据源配置
 *
 * @author luo
 *
 */
@Configuration
public class DatasourceConfig {

    @Autowired
    Environment env;

    /**
     * Write data source druid data source.
     *
     * @return the druid data source
     */
    @Primary
    @Bean(name = "writeDataSource")
    @ConfigurationProperties("spring.datasource.write")
    public DruidDataSource writeDataSource() {

        System.out.println("+++++++++++++++++" + env.getProperty("spring.datasource.write.url"));
        return new DruidDataSource();
    }

    /**
     * Read data source druid data source.
     *
     * @return the druid data source
     */
    @Bean(name = "readDataSource")
    @ConfigurationProperties("spring.datasource.read")
    public DruidDataSource readDataSource() {
        return new DruidDataSource();
    }

    /**
     * Dynamic data source data source.
     *
     * @return the data source
     */
    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        dynamicDataSource.setWriteDataSource(writeDataSource());
        dynamicDataSource.setReadDataSource(readDataSource());

        return dynamicDataSource;
    }

    /**
     * Dynamic transaction manager data source transaction manager.
     *
     * @param dynamicDataSource the dynamic data source
     * @return the data source transaction manager
     */
    @Bean(name = "dynamicTransactionManager")
    public DataSourceTransactionManager dynamicTransactionManager(@Qualifier("dynamicDataSource") DataSource dynamicDataSource) {
        return new DynamicDataSourceTransactionManager(dynamicDataSource);
    }

    /**
     * Dynamic sql session factory sql session factory.
     *
     * @param dynamicDataSource the dynamic data source
     * @param properties        the properties
     * @return the sql session factory
     */
    @Bean
    @ConfigurationProperties(prefix = MybatisProperties.MYBATIS_PREFIX)
    public SqlSessionFactory dynamicSqlSessionFactory(
            @Qualifier("dynamicDataSource") DataSource dynamicDataSource,
            MybatisProperties properties) {

//        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
//        sessionFactory.setDataSource(dynamicDataSource);
//        sessionFactory.setVfs(SpringBootVFS.class);
//        sessionFactory.setTypeAliasesPackage(properties.getTypeAliasesPackage());
//        sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(properties.getConfigLocation()));
//        sessionFactory.setMapperLocations(properties.resolveMapperLocations());

        final MybatisSqlSessionFactoryBean sessionFactory = new MybatisSqlSessionFactoryBean();
        sessionFactory.setDataSource(dynamicDataSource);
        sessionFactory.setVfs(SpringBootVFS.class);
        if (StringUtils.hasLength(properties.getTypeAliasesPackage())) {
            sessionFactory.setTypeAliasesPackage(properties.getTypeAliasesPackage());
        }
        if (StringUtils.hasText(properties.getConfigLocation())) {
            sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(properties.getConfigLocation()));
        }
        if (!ObjectUtils.isEmpty(properties.resolveMapperLocations())) {
            sessionFactory.setMapperLocations(properties.resolveMapperLocations());
        }

        //翻页插件
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        paginationInterceptor.setLocalPage(true);
        sessionFactory.setPlugins(new Interceptor[]{
                paginationInterceptor
        });
        //全局配置
        GlobalConfiguration globalConfig = new GlobalConfiguration();
        globalConfig.setDbType(DBType.MYSQL.getDb());
        globalConfig.setIdType(IdType.INPUT.getKey());
        globalConfig.setDbColumnUnderline(true);
        //热加载
        //globalConfig.setRefresh(true);
        //自动填充
        globalConfig.setMetaObjectHandler(new MyMetaObjectHandler());
        sessionFactory.setGlobalConfig(globalConfig);

        try {
            return sessionFactory.getObject();
        } catch (Exception e) {
            throw new SystemException(e);
        }
    }
}

根本原因都找到了，但是却不知道是哪一行报错的。 就像水中的月亮，看起来近在咫尺，却远在天边。干脆DruidDataSource 进去看看， 加几个断点吧！

做了一些代码上的注释/调整后，发现这样的错误：

detailMessage = "Error creating bean with name 'writeDataSource': Could not bind properties to 'DruidDataSource' : prefix=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true"
cause = {BindException@} "org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'spring.datasource.write' to com.alibaba.druid.pool.DruidDataSource"
 target = {Bindable@} "[Bindable@36eeef8b type = com.alibaba.druid.pool.DruidDataSource, value = 'provided', annotations = array<Annotation>[@org.springframework.boot.context.properties.ConfigurationProperties(prefix=spring.datasource.write, value=spring.datasource.write, ignoreInvalidFields=false, ignoreUnknownFields=true)]]"
 property = {ConfigurationProperty@} "[ConfigurationProperty@49384031 name = spring.datasource.write.username, value = '${MYSQL_DB_USERNAME:elppm_user}', origin = "spring.datasource.write.username" from property source "bootstrapProperties"]"
 name = {ConfigurationPropertyName@} "spring.datasource.write"
 detailMessage = "Failed to bind properties under 'spring.datasource.write' to com.alibaba.druid.pool.DruidDataSource"
 cause = {IllegalStateException@} "java.lang.IllegalStateException: Unable to set value for property username"
  detailMessage = "Unable to set value for property username"
  cause = {InvocationTargetException@} "java.lang.reflect.InvocationTargetException"
  stackTrace = {StackTraceElement[]@}
  suppressedExceptions = {Collections$UnmodifiableRandomAccessList@}  size =
 stackTrace = {StackTraceElement[]@}
 suppressedExceptions = {Collections$UnmodifiableRandomAccessList@}  size = 

这个错误依旧没能解决问题。 但 这回我聪明了， 不断的展开cause， 我发现了 InvocationTargetException, 但是 这个发型并没有什么用。

调试 DruidDataSource 找找setUsername看看， 没有发现，找父类 DruidAbstractDataSource， 发现了，

    public void setUsername(String username) {
        if (this.inited) {
            throw new UnsupportedOperationException();
        } else {
            this.username = username;
        }
    }

原来如此， inited 引起的。 加断点， 果然如此， 就是说， 如果init 过了， 再次setUsername 是会报错的！ 线程堆栈是这样的：

setUsername:, DruidAbstractDataSource (com.alibaba.druid.pool)
invoke:-, GeneratedMethodAccessor275 (sun.reflect)
invoke:, DelegatingMethodAccessorImpl (sun.reflect)
invoke:, Method (java.lang.reflect)
setValue:, JavaBeanBinder$BeanProperty (org.springframework.boot.context.properties.bind)
bind:, JavaBeanBinder (org.springframework.boot.context.properties.bind)
bind:, JavaBeanBinder (org.springframework.boot.context.properties.bind)
bind:, JavaBeanBinder (org.springframework.boot.context.properties.bind)
lambda$null$:, Binder (org.springframework.boot.context.properties.bind)
apply:-,  (org.springframework.boot.context.properties.bind.Binder$$Lambda$)
accept:, ReferencePipeline$$ (java.util.stream)
tryAdvance:, ArrayList$ArrayListSpliterator (java.util)
forEachWithCancel:, ReferencePipeline (java.util.stream)
copyIntoWithCancel:, AbstractPipeline (java.util.stream)
copyInto:, AbstractPipeline (java.util.stream)
wrapAndCopyInto:, AbstractPipeline (java.util.stream)
evaluateSequential:, FindOps$FindOp (java.util.stream)
evaluate:, AbstractPipeline (java.util.stream)
findFirst:, ReferencePipeline (java.util.stream)
lambda$bindBean$:, Binder (org.springframework.boot.context.properties.bind)
get:-,  (org.springframework.boot.context.properties.bind.Binder$$Lambda$)
withIncreasedDepth:, Binder$Context (org.springframework.boot.context.properties.bind)
withBean:, Binder$Context (org.springframework.boot.context.properties.bind)
access$:, Binder$Context (org.springframework.boot.context.properties.bind)
bindBean:, Binder (org.springframework.boot.context.properties.bind)
bindObject:, Binder (org.springframework.boot.context.properties.bind)
bind:, Binder (org.springframework.boot.context.properties.bind)
bind:, Binder (org.springframework.boot.context.properties.bind)
bind:, Binder (org.springframework.boot.context.properties.bind)
bind:, ConfigurationPropertiesBinder (org.springframework.boot.context.properties)
bind:, ConfigurationPropertiesBindingPostProcessor (org.springframework.boot.context.properties)
postProcessBeforeInitialization:, ConfigurationPropertiesBindingPostProcessor (org.springframework.boot.context.properties)
applyBeanPostProcessorsBeforeInitialization:, AbstractAutowireCapableBeanFactory (org.springframework.beans.factory.support)
initializeBean:, AbstractAutowireCapableBeanFactory (org.springframework.beans.factory.support)
initializeBean:, AbstractAutowireCapableBeanFactory (org.springframework.beans.factory.support)
rebind:, ConfigurationPropertiesRebinder (org.springframework.cloud.context.properties)
rebind:, ConfigurationPropertiesRebinder (org.springframework.cloud.context.properties)
onApplicationEvent:, ConfigurationPropertiesRebinder (org.springframework.cloud.context.properties)
onApplicationEvent:, ConfigurationPropertiesRebinder (org.springframework.cloud.context.properties)
doInvokeListener:, SimpleApplicationEventMulticaster (org.springframework.context.event)
invokeListener:, SimpleApplicationEventMulticaster (org.springframework.context.event)
multicastEvent:, SimpleApplicationEventMulticaster (org.springframework.context.event)
publishEvent:, AbstractApplicationContext (org.springframework.context.support)
publishEvent:, AbstractApplicationContext (org.springframework.context.support)
refresh:, ContextRefresher (org.springframework.cloud.context.refresh)
handle:, RefreshEventListener (org.springframework.cloud.endpoint.event)
invoke:-, GeneratedMethodAccessor286 (sun.reflect)
invoke:, DelegatingMethodAccessorImpl (sun.reflect)
invoke:, Method (java.lang.reflect)
doInvoke:, ApplicationListenerMethodAdapter (org.springframework.context.event)
processEvent:, ApplicationListenerMethodAdapter (org.springframework.context.event)
onApplicationEvent:, ApplicationListenerMethodAdapter (org.springframework.context.event)
doInvokeListener:, SimpleApplicationEventMulticaster (org.springframework.context.event)
invokeListener:, SimpleApplicationEventMulticaster (org.springframework.context.event)
multicastEvent:, SimpleApplicationEventMulticaster (org.springframework.context.event)
publishEvent:, AbstractApplicationContext (org.springframework.context.support)
publishEvent:, AbstractApplicationContext (org.springframework.context.support)
receiveConfigInfo:, NacosContextRefresher$ (org.springframework.cloud.alibaba.nacos.refresh)
run:, CacheData$ (com.alibaba.nacos.client.config.impl)
safeNotifyListener:, CacheData (com.alibaba.nacos.client.config.impl)
checkListenerMd5:, CacheData (com.alibaba.nacos.client.config.impl)
run:, ClientWorker$LongPollingRunnable (com.alibaba.nacos.client.config.impl)
runWorker:, ThreadPoolExecutor (java.util.concurrent)
run:, ThreadPoolExecutor$Worker (java.util.concurrent)
run:, Thread (java.lang)

可以看到publishEvent ， 可以肯定的是 这个publishEvent 正是前面的 NacosContextRefresher.this.applicationContext.publishEvent 方法 ！！ （这堆栈好深啊！） 仔细观察堆栈，发现 有个rebind 方法，感觉好奇怪（ 后面发现问题就是这个引起的！！)

那第一次init 是什么时候呢？ 调试发现是dynamicSqlSessionFactory 方法的 return sessionFactory.getObject();

还是不清楚 咋回事。 问题可怎么解决呢？？

Oh my God!!!

上网一把搜索，无果！ 没见到同样问题的出现。 难道这个问题就我一个人碰到吗？ 难道nacos 就我一个人用吗？？？

查看 https://blog.csdn.net/qq_37859539/article/details/81592954  https://blog.csdn.net/JAdroid/article/details/80490679  https://github.com/alibaba/druid/issues/2507 ， 难道是  filter 的问题？

查看https://github.com/alibaba/nacos issue， 没有。。

不至于这么大的坑， 就一个人碰到吧！ 感觉是哪个哪个的版本 问题吧，  druid 从 1.0.26  升级到了 1.1.5 ， 再次观察 setUsername 方法：

    public void setUsername(String username) {
        if (!StringUtils.equals(this.username, username)) {
            if (this.inited) {
                throw new UnsupportedOperationException();
            } else {
                this.username = username;
            }
        }
    }

我一下子就豁然开朗！

原来如此， 这里的这个判断是不可少的吧！ nacos 会每个30 s 就去获取配置， 然后rebind， 但是druid-1.0.26 rebind 就会报错， 报错有没有打印出来！ 我擦。 druid-1.1.5 就不会有这个问题了！检查其他方法， 发现都做了 !StringUtils.equals 判断。

升级就对了嘛！原来 nacos 并没有错， 30s 重新获取配置然后重新绑定都是正确的， 逻辑都是没有问题的！ 原来是 druid的 大坑！！