SpringMVC项目里面是不是一定要有Service层？

Question

看了你百度提问里面其他人的回答，我觉得他们的回答貌似没有正面解决你的问题，我来说说我的观点吧首先springMVC是不包括service和DAO的，我想这个你应该清楚了
然后在注入方面，一般来说action层注入的是service层组件，service层里注入的是DAO组件，在项目运行的时候就是action层调用业务层的方法去实现业务，业务层调用DAO成的方法来查询数据。
但是如果楼主的架构中没有service层，这也是可以的，也就是说楼主只有action和DAO两层，这样的话，楼主可以直接在action层里面注入DAO层组件，然后楼主的action在接收请求后直接在action层里面实现业务，然后调用DAO层的方法查询数据。
所以答案就是不一定需要service层。至于楼主的错误，应该是楼主在action层里面注入DAO层组件的时候发生了错误。具体错误，楼主需要贴代码才能看得出来！以上纯属个人观点，谢谢！

Answer 1

首先先谢谢你的回答，终于有一个正面回答我的问题了！！我这就把代码贴上来，大家帮忙看一下~~
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <display-name></display-name>
    <context-param>
     <param-name>contextConfigLocation</param-name>
     <param-value>classpath:/applicationContext.xml</param-value>
    </context-param>
    <servlet>
     <servlet-name>springMVC</servlet-name>
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <init-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>classpath:/springMVC.xml</param-value>
     </init-param>
     <load-on-startup>1</load-on-startup>
   </servlet>
   <servlet-mapping>
     <servlet-name>springMVC</servlet-name>
     <url-pattern>*.do</url-pattern>
   </servlet-mapping>
   <welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
</web-app>applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
    http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.1.xsd"
>


<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName"
value="com.mysql.jdbc.Driver">
</property>
<property name="url"
value="jdbc:mysql://127.0.0.1:3306/secondhand">
</property>
<property name="username" value="root"></property>
<property name="password" value="199209"></property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</prop>
</props>
</property>
<property name="annotatedClasses">
<list>
<value>com.secondhand.dao.Browse</value>
<value>com.secondhand.entity.Browse</value>
<value>com.secondhand.entity.Operation</value>
<value>com.secondhand.entity.Collection</value>
<value>com.secondhand.entity.OperationInfo</value>
<value>com.secondhand.entity.WishList</value>
<value>com.secondhand.entity.GoodsState</value>
<value>com.secondhand.entity.Evaluation</value>
<value>com.secondhand.entity.Type</value>
<value>com.secondhand.entity.Goods</value>
<value>com.secondhand.entity.User</value></list>
</property>
</bean>
<context:annotation-config />
<bean id="BrowseDAO" class="com.secondhand.dao.BrowseDAO"></bean>
<bean id="UserDAO"  class="com.secondhand.dao.UserDAO">
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>
<bean id="TypeDAO" class="com.secondhand.dao.TypeDAO"></bean>
<bean id="EvaluationDAO" class="com.secondhand.dao.EvaluationDAO"></bean>
<bean id="GoodsStateDAO" class="com.secondhand.dao.GoodsStateDAO"></bean>
<bean id="GoodsDAO" class="com.secondhand.dao.GoodsDAO"></bean>
<bean id="WishListDAO" class="com.secondhand.dao.WishListDAO"></bean>
<bean id="OperationDAO" class="com.secondhand.dao.OperationDAO"></bean>
<bean id="OperationInfoDAO"
class="com.secondhand.dao.OperationInfoDAO">
</bean>
<bean id="CollectionDAO" class="com.secondhand.dao.CollectionDAO"></bean>
</beans>
SpringMVC.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mvc="http://www.springframework.org/schema/mvc"
 xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <mvc:annotation-driven/>
<context:component-scan   base-package="com.secondhand.controller"  /> <bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix">
<value>/WEB-INF/jsp/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>   <bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver"
p:defaultEncoding="utf-8" />
    
</beans>

Answer 2

UserController
package com.secondhand.controller;import java.io.IOException;
import java.util.Map;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;import com.secondhand.dao.UserDAO;
import com.secondhand.entity.User;/**
 * @author ChenJian
 *
 */
@Controller
@RequestMapping("/user")
public class UserController {

//@Resource(name="UserDAO")
@Autowired
UserDAO UserDAO;

@SuppressWarnings("unchecked")
@RequestMapping(value="/login.do", method=RequestMethod.POST)
public String login(HttpServletRequest request, @SuppressWarnings("rawtypes") Map map, HttpSession session) throws IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
User user=new User();
if(username!=null&&password!=null)
{
System.out.println(username+""+password);
//System.out.println(userDao.getUser(username, password).toString());
user = UserDAO.getUser(username, password);
//user = userDao.findByUserName(username).get(0);
}

if (null == user) {
map.put("error", "用户名或密码错误");
return "error";
}
return "main";
}}UserDao
package com.secondhand.dao;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.LockMode;
import org.springframework.context.ApplicationContext;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import com.secondhand.entity.User;/**
  * A data access object (DAO) providing persistence and search support for User entities.
  * Transaction control of the save(), update() and delete() operations 
can directly support Spring container-managed transactions or they can be augmented to handle user-managed Spring transactions. 
Each of these methods provides additional information for how to configure it for the desired type of transaction control. 
 * @see com.secondhand.dao.User
  * @author MyEclipse Persistence Tools 
 */
public class UserDAO extends HibernateDaoSupport  {
 private static final Log log = LogFactory.getLog(UserDAO.class);
//property constants
public static final String PASSWORD = "password";
public static final String CREDIT = "credit";
public static final String USER_NAME = "userName";
public static final String SEX = "sex";
public static final String DEPARTMENT = "department";
public static final String LABEL = "label";
public static final String TELEPHONE = "telephone";
public static final String ADDRESS = "address";
public static final String EMAIL = "email";
public static final String NUMBER = "number"; protected void initDao() {
//do nothing
}
    
    public void save(User transientInstance) {
        log.debug("saving User instance");
        try {
            getHibernateTemplate().save(transientInstance);
            log.debug("save successful");
        } catch (RuntimeException re) {
            log.error("save failed", re);
            throw re;
        }
    }
    
public void delete(User persistentInstance) {
        log.debug("deleting User instance");
        try {
            getHibernateTemplate().delete(persistentInstance);
            log.debug("delete successful");
        } catch (RuntimeException re) {
            log.error("delete failed", re);
            throw re;
        }
    }

/**
 * 执行带参的HQL查询
 * 
 * @param sql
 * @param params
 * @return 查询结果
 */
@SuppressWarnings("unchecked")
public List<User> find(String hql, Object... params) {
return getHibernateTemplate().find(hql,params);
}
    
    public User findById( java.lang.Integer id) {
        log.debug("getting User instance with id: " + id);
        try {
            User instance = (User) getHibernateTemplate()
                    .get("com.secondhand.dao.User", id);
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }
    
    public User getUser(String username, String password) {
String hql = "from User user where user.userName=? and user.password=?";
Object[] args = new Object[]{username, password};
List<User> list = this.find(hql, args);
if (list.size() == 0)
return null;
else
return (User) list.get(0);
}
    
    public List<User> findByExample(User instance) {
        log.debug("finding User instance by example");
        try {
            @SuppressWarnings("unchecked")
List<User> results = (List<User>) getHibernateTemplate().findByExample(instance); 
            log.debug("find by example successful, result size: " + results.size());
            return results;
        } catch (RuntimeException re) {
            log.error("find by example failed", re);
            throw re;
        }
    }    
    
    @SuppressWarnings("unchecked")
public List<User> findByProperty(String propertyName, Object value) {
      log.debug("finding User instance with property: " + propertyName
            + ", value: " + value);
      try {
         String queryString = "from User as model where model." 
          + propertyName + "= ?";
 return getHibernateTemplate().find(queryString, value);
      } catch (RuntimeException re) {
         log.error("find by property name failed", re);
         throw re;
      }
} public List<User> findByPassword(Object password
) {
return findByProperty(PASSWORD, password);
}

public List<User> findByCredit(Object credit
) {
return findByProperty(CREDIT, credit
);
}

public List<User> findByUserName(Object userName
) {
return findByProperty(USER_NAME, userName
);
}

public List<User> findBySex(Object sex
) {
return findByProperty(SEX, sex
);
}

public List<User> findByDepartment(Object department
) {
return findByProperty(DEPARTMENT, department
);
}

public List<User> findByLabel(Object label
) {
return findByProperty(LABEL, label
);
}

public List<User> findByTelephone(Object telephone
) {
return findByProperty(TELEPHONE, telephone
);
}

public List<User> findByAddress(Object address
) {
return findByProperty(ADDRESS, address
);
}

public List<User> findByEmail(Object email
) {
return findByProperty(EMAIL, email
);
}

public List<User> findByNumber(Object number
) {
return findByProperty(NUMBER, number
);
}
public List<?> findAll() {
log.debug("finding all User instances");
try {
String queryString = "from User";
  return getHibernateTemplate().find(queryString);
} catch (RuntimeException re) {
log.error("find all failed", re);
throw re;
}
}

    public User merge(User detachedInstance) {
        log.debug("merging User instance");
        try {
            User result = getHibernateTemplate()
                    .merge(detachedInstance);
            log.debug("merge successful");
            return result;
        } catch (RuntimeException re) {
            log.error("merge failed", re);
            throw re;
        }
    }    public void attachDirty(User instance) {
        log.debug("attaching dirty User instance");
        try {
            getHibernateTemplate().saveOrUpdate(instance);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }
    
    public void attachClean(User instance) {
        log.debug("attaching clean User instance");
        try {
            getHibernateTemplate().lock(instance, LockMode.NONE);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    } public static UserDAO getFromApplicationContext(ApplicationContext ctx) {
     return (UserDAO) ctx.getBean("UserDAO");
}


}

Answer 3

User
package com.secondhand.entity;import java.sql.Timestamp;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;/**
 * User entity. @author MyEclipse Persistence Tools
 */
@Entity
@Table(name = "user", catalog = "secondhand")
public class User implements java.io.Serializable { // Fields /**
 * 
 */
private static final long serialVersionUID = 1L;
private Integer useId;
private String password;
private String credit;
private String userName;
private String sex;
private String department;
private String label;
private String telephone;
private String address;
private String email;
private Timestamp registrationTime;
private String number; // Constructors /** default constructor */
public User() {
} /** full constructor */
public User(String password, String credit, String userName, String sex,
String department, String label, String telephone, String address,
String email, Timestamp registrationTime, String number) {
this.password = password;
this.credit = credit;
this.userName = userName;
this.sex = sex;
this.department = department;
this.label = label;
this.telephone = telephone;
this.address = address;
this.email = email;
this.registrationTime = registrationTime;
this.number = number;
}
// Property accessors
@Id
@GeneratedValue
@Column(name = "Use_id", unique = true, nullable = false)
public Integer getUseId() {
return this.useId;
} public void setUseId(Integer useId) {
this.useId = useId;
} @Column(name = "Password", nullable = false, length = 20)
public String getPassword() {
return this.password;
} public void setPassword(String password) {
this.password = password;
} @Column(name = "Credit", nullable = false, length = 10)
public String getCredit() {
return this.credit;
} public void setCredit(String credit) {
this.credit = credit;
} @Column(name = "User_name", nullable = false, length = 20)
public String getUserName() {
return this.userName;
} public void setUserName(String userName) {
this.userName = userName;
} @Column(name = "Sex", nullable = false, length = 5)
public String getSex() {
return this.sex;
} public void setSex(String sex) {
this.sex = sex;
} @Column(name = "Department", nullable = false, length = 15)
public String getDepartment() {
return this.department;
} public void setDepartment(String department) {
this.department = department;
} @Column(name = "Label", nullable = false, length = 20)
public String getLabel() {
return this.label;
} public void setLabel(String label) {
this.label = label;
} @Column(name = "Telephone", nullable = false, length = 20)
public String getTelephone() {
return this.telephone;
} public void setTelephone(String telephone) {
this.telephone = telephone;
} @Column(name = "Address", nullable = false, length = 50)
public String getAddress() {
return this.address;
} public void setAddress(String address) {
this.address = address;
} @Column(name = "Email", nullable = false, length = 20)
public String getEmail() {
return this.email;
} public void setEmail(String email) {
this.email = email;
} @Column(name = "Registration_time", nullable = false, length = 19)
public Timestamp getRegistrationTime() {
return this.registrationTime;
} public void setRegistrationTime(Timestamp registrationTime) {
this.registrationTime = registrationTime;
} @Column(name = "number", nullable = false, length = 20)
public String getNumber() {
return this.number;
} public void setNumber(String number) {
this.number = number;
}}

Answer 4

SpringMVC的配置文件里推荐仅包含Controller层的配置.
对于Service的配置方法applicationContext中去配置

Answer 5

注解我用的比较少，不过在控制层里面的被注入的属性是不是应该也要有set和get方法啊？楼主现在是没有的。
另外既然楼主的使用了注解来注入属性的话，为什么不直接用注解来配置bean呢？还要在xml文件中用<bean>标签配置干什么？

Answer 6

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.secondhand.dao.UserDAO com.secondhand.controller.UserController.UserDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.secondhand.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
我在Controller里面加了UserDAO的Set和Get还是不行……public void setUserDAO(UserDAO UserDAO)
{
this.UserDAO = UserDAO;
}

public UserDAO getUserDAO()
{
return this.UserDAO;
}
我在XML写Bean是因为我之前是用Hibernate生成DAO的，它自动生成的时候就直接在配置文件里面写好了，我觉得它既然已经写在XML里面了，怎么会找不到呢？

Answer 7

@Autowired
这儿注解，我姐的有一个默认的name属性，也就是
@Autowired("name")
这个name属性可以不写，但是不写的情况下默认应该是属性名，在你那里也就是UserDAO，但是一般来说我们的属性名都是要以小写开头，不知道楼主的属性名是大写开头的情况下@Autowired这个标签默认的name到底是UserDao还是userDao了，楼主可以在@Autowired后面加上@Autowired("UserDao")再试试，但是不保证能行得通！

Answer 8

没有在spring中对userDAO做注册当然注入不了  或者在userDAO类前加responsitroy注解