SpringIOC的应用

导入需要的jar包

配置文件为:

一般不用注解操作时使用<bean id=" " class=" ">来创建对象

<?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-3.2.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-3.2.xsd">
    <!-- 开启注解 用于激活那些已经在spring容器里注册过的bean（无论是通过xml的方式还是通过package sanning的方式）上面的注解，是一个注解处理工具。-->
    <context:annotation-config></context:annotation-config>
    <bean id="userDao" class="cn.bdqn.dao.impl.UserDaoImpl"></bean>
    <bean id="userService" class="cn.bdqn.service.impl.UserServiceImpl"></bean>
</beans>

测试类中可以:

@Test
    public void testSpring1(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = (UserService)ac.getBean("userService");
        User u = new User();
        userService.addUser(u);  //运行userServiceimpl(在xml中别名为userService)中roleShow()方法
}

 

如果完全使用注解操作,那么配置文件里就可以这样写

<?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-3.2.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-3.2.xsd">
    <!-- 加入注解扫描  <context:component-scan>除了具
    有<context:annotation-config>的功能之外，
    <context:component-scan>还可以在指定的package下扫描以及注册javabean 。-->    
    <context:component-scan base-package="cn.bdqn"></context:component-scan>
</beans>

测试类中可以:

@Test
    public void testSpring(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("beans-scan.xml");
        User user = (User)ac.getBean("user");
        user.getRole().roleShow();  //运行roleShow()方法
}

使用注解定义bean:

@Component 用于所有使用注解定义bean

@Component("role")   //相当于<bean id="role" class="cn.bdqn.entity.Role"></bean>
public class Role { 

@Repository 用于标注DAO类

@Repository("userDao")  
public class UserDaoImpl implements UserDao{

@Service 用于标注Service类

@Service("userService")
public class UserServiceImpl implements UserService{

@Controller 用户标注业务类