使用Struts2時(shí)做CRUD時(shí)，每個(gè)action都需要寫相同重復(fù)的代碼，于是就想著將這些個(gè)代碼放到一個(gè)父類中，子類直接使用父類中的方法。

　　但是由于保存的時(shí)候需要傳遞一個(gè)具體的實(shí)體，而每個(gè)action功能不一樣，傳遞的實(shí)體也不一樣，于是就想到了反射。

　　子類：

public class UserAction extends BaseAction<User> {}

　　父類

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(); //獲取泛型類型數(shù)組        this.clazz = (Class<T>) pt.getActualTypeArguments()[0]; //獲取泛型類型    }    protected T model;    @Override    public T getModel() { //通過(guò)傳入不同的泛型類型，獲取具體的實(shí)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;}