泛型的反射

package cn.itcast.oa.base;

import java.lang.reflect.ParameterizedType;

import javax.annotation.Resource;

import cn.itcast.oa.service.DepartmentService;
import cn.itcast.oa.service.RoleService;
import cn.itcast.oa.service.UserService;

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 {
            // 通过反射获取model的真实类型
            ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();
            Class<T> clazz = (Class<T>) pt.getActualTypeArguments()[0];
            // 通过反射创建model的实例
            model = clazz.newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public T getModel() {
        return model;
    }

    // =============== Service实例的声明 ==================
    @Resource
    protected RoleService roleService;
    @Resource
    protected DepartmentService departmentService;
    @Resource
    protected UserService userService;

}

抽象类是不能实例化的，所以抽象类里面的this是指实际调用中它的派生类的实例化对象

参考文章：

http://blog.csdn.net/liang5630/article/details/40185591