在父类中反射获取泛型类型

　　使用Struts2时做CRUD时，每个action都需要写相同重复的代码，于是就想着将这些个代码放到一个父类中，子类直接使用父类中的方法。

　　但是由于保存的时候需要传递一个具体的实体，而每个action功能不一样，传递的实体也不一样，于是就想到了反射。

　　子类：

public class UserAction extends BaseAction<User> {}

　　父类

public abstract class BaseAction<T> extends ActionSupport implements RequestAware, ModelDriven<T> {PRotected Map<String, Object> request;    protected Long id;    private Class<T> clazz = null;    public BaseAction() {        // TODO Auto-generated constructor stub        ParameterizedType pt = (ParameterizedType) this.getClass()                .getGenericSuperclass(); //获取泛型类型数组        this.clazz = (Class<T>) pt.getActualTypeArguments()[0]; //获取泛型类型    }    protected T model;    @Override    public T getModel() { //通过传入不同的泛型类型，获取具体的实例        try {            model = clazz.newInstance();        } catch (Exception e) {            throw new RuntimeException(e);        }        if (id != null) {            if (model instanceof Department) {                model = (T) departmentService.getById(id);            } else if (model instanceof Role) {                model = (T) roleService.getById(id);            } else if (model instanceof User) {                model = (T) userService.getById(id);            } else if (model instanceof Privilege) {                model = (T) privilegeService.getById(id);            }        }        return model;    }    @Override    public void setRequest(Map<String, Object> arg0) {        request = arg0;    }    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    @Resource    protected IDepartmentService departmentService;    @Resource    protected IRoleService roleService;    @Resource    protected IUserService userService;    @Resource    protected iprivilegeService privilegeService;}