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问defineClass用于ActiveJdbc模型抛出异常
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Stack Overflow用户

提问于 2017-01-10 03:53:36

回答 2查看 423关注 0票数 0

当我试图使用defineClass (findClass URLClassLoader或自实现ClassLoader)连接我的模型类时，会出现异常。

正在加载任何其他方法，但不允许动态重载类。

@Table("accounts")
@BelongsToParents({
  @BelongsTo(parent = Customer.class, foreignKeyName = "Customer"),
  @BelongsTo(parent = Currency.class, foreignKeyName = "Currency")
})
public class Account extends Document{
  public static DocFields prepareDocument(...){

    ... fields = new ...(getTableName());
    ...
  }
...
}

public abstract class Document extends Model{
  public static DocFields prepareDocument(Session session){
    return null;
  }
  ...
}

public class DynCLoader extends ClassLoader {

  public DynCLoader(ClassLoader parentClass) {
    super(parentClass);
  }
  @Override
  public Class<?> loadClass(String className) throws ClassNotFoundException {
    if(StrFuncs.isEmpty(className)){
      throw new ClassNotFoundException("Ошибка в модуле DynCLoader, в функцие loadClass. Детали: className is empty");
    }
    try {
      ...
      if(...){ // Загрузка нового, неопределенного класса
        Class<?> clazz;
        try{
          String url = "file:"+...+".class";
          URL myUrl = new URL(url);
          URLConnection connection = myUrl.openConnection();
          InputStream input = connection.getInputStream();
          ByteArrayOutputStream buffer = new ByteArrayOutputStream();
          int data = input.read();
          while(data != -1){
              buffer.write(data);
              data = input.read();
          }
          input.close();
          byte[] classData = buffer.toByteArray();
          clazz = defineClass(className, classData, 0, classData.length);
          ...
          return clazz;
        }
        catch (FileNotFoundException ex) {
          clazz = Class.forName(className);
          ...
          return clazz;
        }
        catch (MalformedURLException ex) {
          ...
          return null;
        }
        catch (Throwable ex) {
          try{
            clazz = Class.forName(className, true, this);
            return clazz;
          }
          catch(ClassNotFoundException oErr){
            ...
          }
          ...
          return null;
        }
      }
      else if(...) // Загрузка системного класса
        return Class.forName(className);
      else{
        return Class.forName(className, true, this);
      }
    }
    catch (ClassNotFoundException ex) {
      throw ex;
    }
  }
}

日志：

[main] INFO org.javalite.activejdbc.DB - Opened connection: com.mysql.jdbc.JDBC4Connection@49fd9b
[main] INFO org.javalite.activejdbc.ConnectionsAccess - Attached connection named: default: to current thread: com.mysql.jdbc.JDBC4Connection@49fd9b. Extra info: jdbc:mysql://127.0.0.1:3306/***
[main] INFO org.javalite.activejdbc.Configuration - Load models from: file:/***/Product/***/Server/target/classes/activejdbc_models.properties
[main] INFO org.javalite.activejdbc.Configuration - Load models from: file:/***/Kernel/Server/target/classes/activejdbc_models.properties
[main] INFO org.javalite.activejdbc.Registry - Registered model: class kz.mwb.qupris.server.data.model.Account
***
[main] INFO org.javalite.activejdbc.Registry - Registered model: class kz.mwb.qupris.server.data.model.User
***
[main] INFO org.javalite.activejdbc.Registry - Fetched metadata for table: accounts
***
[main] INFO org.javalite.activejdbc.Registry - Fetched metadata for table: usertable
***
[main] INFO org.javalite.activejdbc.MetaModel - Association found: Customer  ----------<  Account, type: has-many
[main] INFO org.javalite.activejdbc.MetaModel - Association found: Account  >----------  Customer, type: belongs-to
***
[main] INFO org.javalite.activejdbc.cache.QueryCache - MISS, "SELECT * FROM *** WHERE ***
***
[Thread-20] INFO org.javalite.activejdbc.DB - Opened connection: com.mysql.jdbc.JDBC4Connection@1db686
[Thread-20] INFO org.javalite.activejdbc.ConnectionsAccess - Attached connection named: default: to current thread: com.mysql.jdbc.JDBC4Connection@1db686. Extra info: jdbc:mysql://127.0.0.1:3306/***
[Thread-20] INFO org.javalite.activejdbc.LazyList - Query: "SELECT * FROM *** WHERE ***, took: 5 milliseconds
***
00:42:52 > 34 > UserLib > ERROR > java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at kz.mwb.qupris.server.tool.loader.Include.processMethod(Include.java:111)
    at kz.mwb.qupris.server.userlib.doDoc.initMod(doDoc.java:59)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at kz.mwb.qupris.server.tool.loader.Include.processMethod(Include.java:111)
    at kz.mwb.qupris.server.tool.loader.Include.EvalFunction(Include.java:31)
    at kz.mwb.qupris.server.engine.ModEngine.MProcess(ModEngine.java:133)
    at kz.mwb.qupris.server.engine.ModEngine.IProcess(ModEngine.java:85)
    at kz.mwb.qupris.server.engine.ModEngine.XProcess(ModEngine.java:203)
    at kz.mwb.qupris.server.engine.Task.ProcessRequest(Task.java:396)
    at kz.mwb.qupris.server.engine.Task.GateWayLine(Task.java:162)
    at kz.mwb.qupris.server.engine.Task.ConnectToGateWay(Task.java:326)
    at kz.mwb.qupris.server.engine.Task.run(Task.java:61)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.javalite.activejdbc.DBException: failed to find metamodel for class kz.mwb.qupris.server.data.model.Account. Are you sure that a corresponding table  exists in DB?
    at org.javalite.activejdbc.Registry.getTableName(Registry.java:414)
    at org.javalite.activejdbc.ModelDelegate.tableNameOf(ModelDelegate.java:326)
    at kz.mwb.qupris.server.data.model.Account.getTableName(Account.java:2831)
    at kz.mwb.qupris.server.data.model.Account.prepareDocument(Account.java:23)
    ... 20 more

java

activejdbc

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回答 2

Stack Overflow用户

发布于 2017-01-11 08:05:42

我把getTableName换成了MetaModels.java，它成功了！

String getTableName(Class<? extends Model> modelClass) {
    MetaModel mm = null;
    for (Map.Entry<Class<? extends Model>, MetaModel> entry : metaModelsByClass.entrySet()){
      if(modelClass.getName().equals(entry.getKey().getName()))
        mm = entry.getValue();
    }
    return mm == null ? null : mm.getTableName();
}

原功能：

String getTableName(Class<? extends Model> modelClass) {
    MetaModel mm = metaModelsByClass.get(modelClass);
    return mm == null ? null : mm.getTableName();
}