@Autowired春季注释

Question

我在春季相对较新，我在理解spring的基本原理方面有问题。

我的控制器

 @Controller
public class HomeController {  

private ContactManager contactManager;

@Autowired
public void setContactManager(ContactManager contactManager) {
    this.contactManager = contactManager;
}

@RequestMapping(value="/")
public ModelAndView listContact(ModelAndView model) throws IOException {
    List<Contact> listContact = contactManager.list();
    model.addObject("listContact", listContact);
    model.setViewName("home");
    return model;
 }
 ...

联系ManagerImpl及接口方法的实现

public class ContactManagerImpl implements ContactManager {
private DataSource dataSource;
private JdbcTemplate jdbcTemplate;

public void setDataSource(DataSource dataSource) {
    this.dataSource = dataSource;
    this.jdbcTemplate = new JdbcTemplate(dataSource);
}
  ...

ContactManager

public interface ContactManager {
public void saveOrUpdate(Contact contact);
public void delete(int contactId);
public Contact get(int contactId);
public List<Contact> list();
 }

和root-context.xml

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/test"/>
    <property name="username" value="root"/>
    <property name="password" value="sec"/>
</bean>

<bean id="managmentService" class="spring.contact.impl.model.ContactManagerImpl">
<property name="dataSource" ref="dataSource"/>
</bean>

我的问题是我犯了错误：

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of
type [spring.contact.api.ContactManager] found for dependency: expected at least 1    
bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

当然，问题在于@Autowired注解。我怎么才能修好它？当我删除@Autowired注释时，我得到了另一个错误: NullPointerException (HomeController中的管理器)。

Answer 1

你的财务总监应该是..。

@Controller
public class HomeController {  

    @Autowired
    @Qualifier("managmentService")
    private ContactManager contactManager;

    @RequestMapping(value="/")
    public ModelAndView listContact(ModelAndView model) throws IOException {
        List<Contact> listContact = contactManager.list();
        model.addObject("listContact", listContact);
        model.setViewName("home");
        return model;
     }
     ...

在您的配置中，还要添加<context:annotation-config />，以便能够使用@Autowired注释。

<context:annotation-config />的一个例子

<?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:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd">

   <context:annotation-config/>
   <!-- bean definitions go here -->

</beans>

Answer 2

将@Autowired注释移动到ContactManager的声明中。

你不需要策划人，把它删掉。