java - CacheException - 反序列化对象时出错 - MyBatis 和 Play

Question

我将 MyBatis 与 playframework 一起使用，一切都运行良好，除了:

当我尝试使用 MyBatis 中内置的默认缓存(xml 映射器文件中的 <cache/> 标记)时，在检索缓存的 select 语句时，我得到了这个堆栈跟踪。

如果我在单元测试(或不涉及 playframework 的另一个应用程序)中运行相同的语句，一切都会正常。

所以，我猜这与 playframework 加载/编译类的方式(某种类加载器问题)有关。

我的项目的目录布局看起来像这样(相关位):

app
  controllers
  data // xml mapping files and java interfaces for ibatis
       // & a class that returns a SqlSessionFactory
    domain // Pojos for SQL results (e.g. User.java)
  models
  views
lib // here is myibatis jar file
(...) // the rest of the standard play framework project

抛出异常的模型方法是这样的:

  public static UserAuthentication findAuthenticatonIdentity(UserId userId){
    SqlSessionFactory sessionFactory = IbatisSessionFactory.getSqlMapper();
    SqlSession session = sessionFactory.openSession();
    AuthMapper authMapper = session.getMapper(AuthMapper.class);

    UserAuthentication ua = authMapper.selectByUserId(userId); // line 162
    session.close();
    return ua;
  }

并且 UserAuthentication 实现了可序列化!

这是堆栈跟踪:

Execution exception (In /app/models/UserModel.java around line 162)
PersistenceException occured : 
 ### Error querying database.  Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
 ### Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication

play.exceptions.JavaExecutionException: 
### Error querying database.  Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
### Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:231)
    at Invocation.HTTP Request(Play!)
Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
### Cause: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:94)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:58)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:90)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:40)
    at $Proxy8.selectByUserId(Unknown Source)
    at models.UserModel.findAuthenticatonIdentity(UserModel.java:162)
    at controllers.securesocial.MySecureSocial.checkAccess(MySecureSocial.java:97)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:504)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:478)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:473)
    at play.mvc.ActionInvoker.handleBefores(ActionInvoker.java:322)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:142)
    ... 1 more
Caused by: org.apache.ibatis.cache.CacheException: Error deserializing object.  Cause: java.lang.ClassNotFoundException: data.domain.UserAuthentication
    at org.apache.ibatis.cache.decorators.SerializedCache.deserialize(SerializedCache.java:94)
    at org.apache.ibatis.cache.decorators.SerializedCache.getObject(SerializedCache.java:50)
    at org.apache.ibatis.cache.decorators.LoggingCache.getObject(LoggingCache.java:50)
    at org.apache.ibatis.cache.decorators.SynchronizedCache.getObject(SynchronizedCache.java:55)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:72)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:100)
    ... 13 more
Caused by: java.lang.ClassNotFoundException: data.domain.UserAuthentication
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:247)
    at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:603)
    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574)
    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1731)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at java.util.ArrayList.readObject(ArrayList.java:593)
    at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at org.apache.ibatis.cache.decorators.SerializedCache.deserialize(SerializedCache.java:91)
    ... 18 more

用户身份验证.java

public class UserAuthentication implements Serializable {

  private int id;
  private String authId;
  private String secret;
  private String token; // Oauth1 token
  private String accessToken; // Oauth2 request token
  private String displayName;
  private String authMethod;
  private String provider;
  private String email;
  private String avatarUrl;
  private Date lastAccess;
  private String password;
  private boolean emailVerified;
  private int userId;
  private String activationUuid;
  private Date activationExpiry;

  // + getters & setters
}

用户ID.java

public class UserId implements java.io.Serializable {
    /**
     * The id the user has in a external service.
     */
    public String id;

    /**
     * The provider this user belongs to.
     */
    public ProviderType provider; // simple enum
}

Answer 1

抱歉，我想我错了 - 这不是名称冲突，而是类加载器问题。

Play 使用动态类加载机制来检测源代码的更改并通过字节码注入(inject)增强方法。 http://groups.google.com/group/play-framework/browse_frm/thread/359736394ae27902/98445c557833036c

我认为问题可能是 MyBatis 使用常规类加载器 - 因此无法找到通过 Play 机制加载的类。当您将源代码放入 Play 目录时，MyBatis 将使用 Play 类加载器。

以下是一些选项:

1) 将域对象编译到 JAR 文件中。将该 jar 包含在您的项目中: http://groups.google.com/group/play-framework/browse_thread/thread/b54e4e25ae49161b

2) 强制 MyBatis 使用 Play 类加载器 - 在任何 mybatis 调用之前的某个地方

Thread.currentThread().setContextClassLoader(Play.classloader); 

http://groups.google.com/group/play-framework/browse_thread/thread/f4789ee5c20609af/d1412a914dc06851?#d1412a914dc06851

看起来仍然像是一种黑客攻击，但也许它可以缩小您的应用程序源代码的大小。

3) 确保您的类在调用 MyBatis 之前加载。所以，在这种情况下。

Class.forName("data.domain.UserAuthentication");
Class.forName("data.domain.UserId");

这似乎是更糟糕的黑客行为。

我希望其中一个选项适合您。