Spring配置問題：报错

是不是在你的service中没有声明dao

 Invalid property 'userDao_msi' of bean class [com.msi.service.impl.UserServiceImpl]: Bean property 'userDao_msi' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?

Service类里dao对象有正确的get sert方法吗？

<bean id="UserService_msi" class="com.msi.service.impl.UserServiceImpl">
  <property name="userDao_msi">
   <ref local="userDao_msi" />
  </property>

 </bean>

注入property name="userDao_msi" 时  ，需要com.msi.service.impl.UserServiceImpl有一个setter方法，方法名为setUserDao_msi，才能成功注入

缺少set/get方法

哥們；按照你說的配置之後，異常消失
不過，如果我這樣測試就出現Exception in thread "main" java.lang.ClassCastException: $Proxy11 cannot be cast to com.msi.service.impl.UserServiceImpl
 at com.msi.service.impl.UserServiceImpl.main(UserServiceImpl.java:33)

--------------------------------------------------------
配置部份
<bean id="userDao_msi" class="com.msi.dao.impl.UserDaoImpl">
  <property name="sessionFactory">
   <ref local="sessionFactory" />
  </property>
</bean>
<bean id="userService" class="com.msi.service.impl.UserServiceImpl">
  <property name="userService_msi">
   <ref local="userDao_msi" />
  </property>
 </bean>

代碼--------------------------------------------
import com.msi.dao.UserDao;
import com.msi.dao.impl.UserDaoImpl;
import com.msi.model.User;
import com.msi.service.UserService;

public class UserServiceImpl implements UserService {

 public UserDao userService_msi;

 public UserDao getuserService_msi() {
  return userService_msi;
 }

 public void setuserService_msi(UserDao userService_msi) {
  this.userService_msi = userService_msi;
 }

 @Override
 public User login(User user) throws Exception {
  // TODO Auto-generated method stub
  return userService_msi.login(user);
 }

 public static void main(String args[]) throws Exception {

  ApplicationContext ctx = new ClassPathXmlApplicationContext(
    "applicationContext.xml");
  UserServiceImpl dao = (UserServiceImpl) ctx.getBean("userService");
  User user = new User("admin", "admin");
  User u = dao.login(user);
  System.out.println(u);
 }
}
這樣就出現最上面的異常，這是爲什麽呢

UserServiceImpl dao = (UserServiceImpl) ctx.getBean("userService");

改成UserService dao =  (UserService) ctx.getBean("userService");

Spring在实例化的是UserServiceImpl的一个代理对象、实现了UserService接口。所以要有UserService声明dao变量（父类引用指向子类实例）