获取范型类的子类的实际类型的方法

package cn.itcast.oa.base;

import java.lang.reflect.ParameterizedType;
import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
@SuppressWarnings("unchecked")
public abstract class BaseDaoImpl<T> implements BaseDao<T> {
@Resource
private SessionFactory sessionFactory;

private Class<T> clazz; //这是一个问题，等待解决

public BaseDaoImpl(){
//使用反射技术得到T的真实类型
ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();//获取当前new的对象的泛型的父类类型
this.clazz = (Class<T>) pt.getActualTypeArguments()[0];//获取第一个类型参数的类型
System.out.println("clazz-->"+this.clazz);
}

/**
* 得到Session
*
* @return
*/
protected Session getSession(){
return sessionFactory.getCurrentSession();
}

@Override
public void save(T entity) {
getSession().save(entity);
}

@Override
public void update(T entity) {
getSession().update(entity);
}

@Override
public void delete(Long id) {
Object obj = getById(id);
if(obj != null){
getSession().delete(obj);
}
}

@Override
public T getById(Long id) {
return (T) getSession().get(clazz, id);
}

@Override
public List<T> getByIds(Long[] ids) {
return getSession().createQuery(//
"FROM " +clazz.getSimpleName()+ " WHERE id IN (:ids)")//
.setParameterList("ids", ids)//
.list();
}

@Override
public List<T> findAll() {
return getSession().createQuery(//
"FROM " + clazz.getSimpleName())//
.list();
}

}

//=================第二个例子========================//

package cn.itcast.oa.base;

import java.lang.reflect.ParameterizedType;

import javax.annotation.Resource;

import cn.itcast.oa.domain.Department;
import cn.itcast.oa.service.DepartmentService;
import cn.itcast.oa.service.RoleService;

import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

public abstract class BaseAction<T> extends ActionSupport implements ModelDriven<T>{

//===============ModelDriven的支持======================//
protected T model;

public BaseAction(){
try{
//通过反射得到model的真实实例
ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();
Class<T> clazz = (Class<T>) pt.getActualTypeArguments()[0];
model = clazz.newInstance();
}catch(Exception e){
throw new RuntimeException(e);
}
}

@Override
public T getModel() {
return model;
}
//===============Service实例的声明======================//
@Resource
protected DepartmentService departmentService;

@Resource
private RoleService roleService;

}