applicationContext注入了为啥是空的？

Question

System.err.println("commonDao:"+commonDao);打印出来是空的，各位帮忙看一下，我看了好久了。
action:
public class UserInfoAction extends BaseAction {
private IUserInfoBiz userInfoBiz;

public IUserInfoBiz getUserInfoBiz() {
    return userInfoBiz;
}

public void setUserInfoBiz(IUserInfoBiz userInfoBiz) {
    this.userInfoBiz = userInfoBiz;
}
public String ajax_json(){
           userInfoBiz.saveUserInfo(userInfo);

Biz：
public class UserInfoBiz extends BaseBiz implements IUserInfoBiz{
IUserInfoDao userInfoDao;

public IUserInfoDao getUserInfoDao() {
    return userInfoDao;
}

public void setUserInfoDao(IUserInfoDao userInfoDao) {
    this.userInfoDao = userInfoDao;
}

public void saveUserInfo(UserInfo userInfo) {
this.userInfoDao.saveUserInfo(userInfo);
}

Dao：
public class UserInfoDao extends BaseDao implements IUserInfoDao {
public void saveUserInfo(UserInfo userInfo) {
System.err.println("commonDao:"+commonDao);
this.commonDao.saveOrUpdate(userInfo);
}

public abstract class BaseDao extends HibernateBaseDao
implements IBaseDao{

 protected ICommonDao commonDao;

public ICommonDao getCommonDao() {
return commonDao;
}

public void setCommonDao(ICommonDao commonDao) {
    this.commonDao = commonDao;
}

public class HibernateCommonDao extends HibernateDaoSupport implements ICommonDao {

applicationContext：

Answer 1

肯定是空的啊，你commonDao没注入到BaseDao中。