Couldn‘t store trigger ‘‘ for ‘‘ job:Couldn‘t retrieve job because the BLOB couldn‘t be ...

解决方案在底部，可以直接跳过前面的分析部分。

具体错误日志如下：

org.quartz.JobPersistenceException: Couldn't store trigger 'Axxxx' for 'Bxxxx' job:Couldn't retrieve job because the BLOB couldn't be deserialized: com.demo.TaskClass; local class incompatible: stream classdesc serialVersionUID = 4545949010006210417, local class serialVersionUID = -7472559171496155799  at org.quartz.impl.jdbcjobstore.JobStoreSupport.storeTrigger(JobStoreSupport.java:1228)  at org.quartz.impl.jdbcjobstore.JobStoreSupport.doUpdateOfMisfiredTrigger(JobStoreSupport.java:1042)  at org.quartz.impl.jdbcjobstore.JobStoreSupport.recoverMisfiredJobs(JobStoreSupport.java:991)  at org.quartz.impl.jdbcjobstore.JobStoreSupport.doRecoverMisfires(JobStoreSupport.java:3264)  at org.quartz.impl.jdbcjobstore.JobStoreSupport$MisfireHandler.manage(JobStoreSupport.java:4012)  at org.quartz.impl.jdbcjobstore.JobStoreSupport$MisfireHandler.run(JobStoreSupport.java:4033) Caused by: org.quartz.JobPersistenceException: Couldn't retrieve job because the BLOB couldn't be deserialized: com.demo.TaskClass; local class incompatible: stream classdesc serialVersionUID = 4545949010006210417, local class serialVersionUID = -7472559171496155799  at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveJob(JobStoreSupport.java:1397)  at org.quartz.impl.jdbcjobstore.JobStoreSupport.storeTrigger(JobStoreSupport.java:1210)  ... 5 common frames omitted Caused by: java.io.InvalidClassException: com.demo.TaskClass; local class incompatible: stream classdesc serialVersionUID = 4545949010006210417, local class serialVersionUID = -7472559171496155799  at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:699)  at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:2003)  at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1850)  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2160)  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1667)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:503)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:461)  at java.util.HashSet.readObject(HashSet.java:341)  at sun.reflect.GeneratedMethodAccessor1011.invoke(Unknown Source)  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)  at java.lang.reflect.Method.invoke(Method.java:498)  at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1184)  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2296)  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2187)  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1667)  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2405)  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2329)  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2187)  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1667)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:503)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:461)  at java.util.HashMap.readObject(HashMap.java:1412)  at sun.reflect.GeneratedMethodAccessor486.invoke(Unknown Source)  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)  at java.lang.reflect.Method.invoke(Method.java:498)  at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1184)  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2296)  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2187)  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1667)  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2405)  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2329)  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2187)  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1667)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:503)  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:461)  at org.quartz.impl.jdbcjobstore.StdJDBCDelegate.getObjectFromBlob(StdJDBCDelegate.java:3201)  at org.quartz.impl.jdbcjobstore.StdJDBCDelegate.selectJobDetail(StdJDBCDelegate.java:860)  at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveJob(JobStoreSupport.java:1390)  ... 6 common frames omitted

1.这个错误真的让我头疼。一开始我不太明白错误在哪里，一直在搜索。"Couldn't retrieve job because the BLOB couldn't be deserialized"关键错误，网上有关于这个错误的解决方案，可以参考https://www.yepk.cn/archives/quartz-error.html

2.通过对计划的查阅，我了解到是因为任务实体类com.demo.TaskClass它被改变了，导致定时器以前不知道这类

其实主要的错误日志就在这里：local class incompatible: stream classdesc serialVersionUID = 12345, local class serialVersionUID = 6789。错误复制步骤，创建A定时任务，定时任务正常工作，然后更改实体类TaskCass的数据结构，比如加个属性，启动服务后就会报这个错，这是因为没有自定义序列化serialVersionUID。

4、创建定时任务实体类要实现Serizlizable接口，这时候启动服务这个类会被分配一个序列化ID也就是serialVersionUID，如果没有自定义序列化ID，那么系统就会给这个类自动生成一个序列化ID，这个序列化ID是根据这个类的hash值生成的，所以修改实体类数据结构后，hash值会变，序列化ID也就变了，就像第三个步骤里由12345变成了6789，导致了定时器去反序列化的时候会去找6789，但是找到了老任务A时，A的序列化ID是12345，定时器就不认识了，就没办法反序列化，就会报错。

5、解决方案：给实体类自定义序列化ID为老的12345即可。

6、代码展示：

//实体类 此时序列化ID是12345
public  class TaskClass implements Serializable {

    private String name;

}
//修改实体类数据结构 此时序列化ID会变成6789
public  class TaskClass implements Serializable {

    private String name;

    private String age;

}
//解决方法 自定义序列化ID为12345,这时这个类的序列化ID就不会因为改变结构而变化了 因为被写死了

public  class TaskClass implements Serializable {

    private static final long serialVersionUID = 12345L;

    private String name;

    private String age;

}

7、关于序列化ID自动生成，因为我们一般也不会自己去定义序列化ID，毕竟自己可能会定义到一个重复的，IDEA有自动生成序列化ID的快捷方式，保证会根据类的HASH值生成序列化ID，这样就不会重复了，操作步骤如下：

进入IDEA->File->setting->Editor->inspections,然后搜索serialVersionUID，勾选以下两个选项，然后Apply

 光标放在类名下面，按Alt+Enter 创建UID即可