是否为每个 class 个实例创建了 Cglib 方法拦截器?
Are Cglib Method Interceptors created per class instance?
我有以下通用的 cglib 方法拦截器实现:
public class EntityInterceptor<T, PK> implements MethodInterceptor{
private EntityChangeType changeType;
private T entity;
private GenericCrudMapper<T,PK> mapper;
public EntityInterceptor(T entity, GenericCrudMapper<T, PK> mapper){
this.entity = entity;
this.mapper = mapper;
}
@Override
public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
// pass through
return proxy.invoke(entity, args);
}
public void setEntityChangeType(EntityChangeType changeType){
this.changeType = changeType;
}
public void saveChanges(){
// @todo
}
}
其中的用法如下:
@Override
public Airport get(String id) {
Airport airport = airportMapper.findById(id);
if(airport != null){
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(Airport.class);
enhancer.setCallback(new EntityInterceptor<>(airport, airportMapper));
airport = (Airport) enhancer.create();
return airport;
}
return airport;
}
我能否安全地假设上面创建的方法拦截器将在每个增强的 class 实例中实例化(换句话说,在分配方法拦截器时,它们不会在所有 class 实例之间共享)?
是的,这一点你可以确定。但是,您的解决方案效率很低,因为每个实例都会生成一个新的 class 。相反,您应该根据拦截器类型创建代理:
// Do once
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(realObject.getClass());
enhancer.setCallbackType(Airport.class);
Class classForProxy = enhancer.createClass();
// Do for each instance
Enhancer.registerCallbacks(classForProxy, new Callback[]{new EntityInterceptor<>(airport, airportMapper});
Object createdProxy = classForProxy.newInstance();
这样您就可以为所有代理实例重复使用一个 class。
我有以下通用的 cglib 方法拦截器实现:
public class EntityInterceptor<T, PK> implements MethodInterceptor{
private EntityChangeType changeType;
private T entity;
private GenericCrudMapper<T,PK> mapper;
public EntityInterceptor(T entity, GenericCrudMapper<T, PK> mapper){
this.entity = entity;
this.mapper = mapper;
}
@Override
public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
// pass through
return proxy.invoke(entity, args);
}
public void setEntityChangeType(EntityChangeType changeType){
this.changeType = changeType;
}
public void saveChanges(){
// @todo
}
}
其中的用法如下:
@Override
public Airport get(String id) {
Airport airport = airportMapper.findById(id);
if(airport != null){
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(Airport.class);
enhancer.setCallback(new EntityInterceptor<>(airport, airportMapper));
airport = (Airport) enhancer.create();
return airport;
}
return airport;
}
我能否安全地假设上面创建的方法拦截器将在每个增强的 class 实例中实例化(换句话说,在分配方法拦截器时,它们不会在所有 class 实例之间共享)?
是的,这一点你可以确定。但是,您的解决方案效率很低,因为每个实例都会生成一个新的 class 。相反,您应该根据拦截器类型创建代理:
// Do once
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(realObject.getClass());
enhancer.setCallbackType(Airport.class);
Class classForProxy = enhancer.createClass();
// Do for each instance
Enhancer.registerCallbacks(classForProxy, new Callback[]{new EntityInterceptor<>(airport, airportMapper});
Object createdProxy = classForProxy.newInstance();
这样您就可以为所有代理实例重复使用一个 class。