Spring Annotation注解：易错点
用注解以来，发现经常漏配置，所以在这把所有需要写注解的地方都列出来。
Action层：
@Component
@Scope("prototype")
public class SendMsgAction extends BaseAction{
private int[] ids;
private SendMsg sendMsg;
@Resource
private SendMsgService sendMsgService;
Dao层：接口并不需要配注解。但是实现层须有如下配置：
1、 public class BaseDaoImpl<T> implements BaseDao<T> {
protected Class clazz;
@Resource
private HibernateTemplate hibernateTemplate;

2、 @Component
public class SendMsgDaoImpl extends BaseDaoImpl<SendMsg> implements SendMsgDao {

Po层：实体类。在这有mappedBy下面细说。
@Entity
@Table(name="t_user")
public class User {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int id;
private String name;
private String pwd;
private String phone;
@OneToMany(mappedBy="user")
private Set<SendMsg> sendMsgs=new HashSet<SendMsg>();//本人发送多份邮件
@OneToMany(mappedBy="receiver")
private Set<ReceiveMsg> receiveMsgs=new HashSet<ReceiveMsg>();
Service层：接口也不需要配注解，实现类须有一下配置：
@Component
public class SendMsgServiceImpl implements SendMsgService {
@Resource
private SendMsgDao smdao;

关于mappedBy属性：一般mappedBy放哪，哪边就生成外键。
凡是加了@Resource的元素，都要有get，set方法