springmvc @Resource 注解方式问题

最新推荐文章于 2022-04-10 15:58:00 发布

最新推荐文章于 2022-04-10 15:58:00 发布 · 225 阅读

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本文探讨了Spring框架中@Autowired与@Resource注解的区别，通过具体的代码示例展示了如何在HelloController类和HelloService类中使用@Autowired进行依赖注入。同时，文章提到了在特定场景下@Resource可能无法正常工作的原因。

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如下代码：在自动注入是采用 @Autowired 可以但是为什么使用@Resource不行呢

在网上看了几个@Autowired和@Resource的区别但还是不明白两个具体不同的配置

HelloController类

public class HelloController implements Controller{

private Logger logger = Logger.getLogger(this.getClass().getName());
private String helloWorld; // 该属性用于获取配置文件中的helloWorld属性
private String viewPage;        // 用于获取配置文件中的viewPage属性
@Autowired  为什么不能使用@Resource
private HelloService helloService;
@SuppressWarnings("unchecked")
public ModelAndView handleRequest(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {
  // 在该方法中处理用户请求
  Map model = new HashMap();
  model.put("helloWorld", getHelloWorld());
  String ss=helloService.getId();
  //model.put("id",helloService.getId());
  //req.setAttribute("ss",ss);
  // 将helloWorld属性存入model中
  res.getWriter().write(ss);
  return null;
  // 调用getViewPage获取要返回的页面
  }
public void setViewPage(String viewPage){
  this.viewPage = viewPage;
  }
public String getViewPage(){
   return this.viewPage;
  }
public void setHelloWorld(String helloWorld){
   this.helloWorld = helloWorld;
   }
public String getHelloWorld(){
   return this.helloWorld;
  }
}

HelloDao类

@Repository
public class HelloDao {
   static ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
  //得到数据源
   private static DataSource ds=(DataSource) context.getBean("dataSource");
   static JdbcTemplate jt1=(JdbcTemplate) context.getBean("jt");
   public String getId(){
    String sql =" select * from test order by id asc limit 1 ";
   Map map =jt1.queryForMap(sql);
   System.out.println(""+map.get("id"));
   return map.get("id").toString();
   }

}

HelloService类

@Service
public class HelloService {
@Autowired  为什么不能使用@Resource
private HelloDao helleDao;

@Cacheable(modelId="testCaching")
public String getId(){
  helleDao.getId();
  return helleDao.getId();

}
}
applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans

xmlns="http://www.springframework.org/schema/beans"
xmlns:ehcache="http://www.springmodules.org/schema/ehcache"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springmodules.org/schema/ehcache
http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
" default-autowire="byName">

<context:annotation-config/>
<bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">
   <property name="dataSource">
    <ref local="dataSource" />
   </property>
</bean>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
   <property name="driverClassName">
    <value>com.mysql.jdbc.Driver</value>
   </property>
   <property name="url">
    <value>jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8</value>
   </property>
   <property name="username">
    <value>root</value>
   </property>
   <property name="password">
    <value>root</value>
   </property>
</bean>
<context:component-scan base-package="test.t" ></context:component-scan>
<ehcache:config configLocation="classpath:ehcache.xml" id="cacheProvider"/>
<ehcache:annotations providerId="cacheProvider">
<ehcache:caching cacheName="testCache" id="testCaching"/>
<ehcache:flushing cacheNames="testCache" id="testFlushing" />
</ehcache:annotations>
</beans>

dispatcherServlet-servlet.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="localeResolver"
  class="org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver">
</bean>

<bean id="urlMapping"
  class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
  <property name="mappings">
   <props>
    <prop key="helloWorld.do">helloWorldAction</prop>
   </props>
  </property>
</bean>

<bean id="viewResolver"
  class="org.springframework.web.servlet.view.InternalResourceViewResolver">
  <property name="viewClass">
   <value>
    org.springframework.web.servlet.view.InternalResourceView
   </value>
  </property>
</bean>

<bean id="helloWorldAction"
  class="test.t.HelloController">
  <property name="helloWorld">
   <value>Hello Spring World!</value>
  </property>
  <property name="viewPage">
   <value>sayHello.jsp</value>
  </property>
</bean>
<import resource="classpath:applicationContext.xml"/>
</beans>
web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>simpleservlet</servlet-name>
<servlet-class>test.SimpleServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>simpleservlet</servlet-name>
<url-pattern>/simpeservlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<login-config>
<auth-method>BASIC</auth-method>
</login-config>
</web-app>