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Spring依赖注入 --- 简单使用说明
Spring依赖注入 --- 简单使用说明
本文将对spring依赖注入的使用做简单的说明，enjoy your time！
1.使用Spring提供的依赖注入
对spring依赖注入的实现方法感兴趣的同学可以参考我的日志：http://www.cnblogs.com/kodoyang/p/Frame_Imitate_Spring.html
我们会用spring提供的ClassPathXmlApplicationContext实现来代替这篇日志中相应的实现
为导入的jar文件配置api对应的Library的jar上右键，选择properties>JavadocLocation鼠标停留在对应的类上，按F1就可以看到对应的api文档ClassPathXmlApplicationContext实现了接口ApplicationContext；接口ApplicationContext继承了BeanFactory的接口
ApplicationContext可以使用的方法更多，所以一般用ApplicationContext
下面是详细的代码：
/Spring_IOC/src/yuki/spring/ioc/pojo/User.java
package yuki.spring.ioc.pojo;public class User { private String username; private String password; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
/Spring_IOC/src/yuki/spring/ioc/dao/UserDAO.java
package yuki.spring.ioc.dao;import yuki.spring.ioc.pojo.User;public interface UserDAO { void save(User u);}
/Spring_IOC/src/yuki/spring/ioc/dao/impl/UserDAOImpl.java
package yuki.spring.ioc.dao.impl;import yuki.spring.ioc.dao.UserDAO;import yuki.spring.ioc.pojo.User;public class UserDAOImpl implements UserDAO { private int daoId; private String daoStatus; public int getDaoId() { return daoId; } public void setDaoId(int daoId) { this.daoId = daoId; } public String getDaoStatus() { return daoStatus; } public void setDaoStatus(String daoStatus) { this.daoStatus = daoStatus; } @Override public void save(User u) { System.out.println(daoId + ", " + daoStatus); System.out.println("user saved..."); }}
/Spring_IOC/src/yuki/spring/ioc/service/UserService.java
package yuki.spring.ioc.service;import yuki.spring.ioc.dao.UserDAO;import yuki.spring.ioc.pojo.User;public class UserService { private UserDAO userDAO; public UserService(UserDAO userDAO) { this.userDAO = userDAO; } public void add(User u){ this.userDAO.save(u); }}
/Spring_IOC/src/beans.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="userDAO" class="yuki.spring.ioc.dao.impl.UserDAOImpl"> <property name="daoId" value="6"></property> <property name="daoStatus" value="good"></property> </bean> <bean id="userService" class="yuki.spring.ioc.service.UserService"> <!-- <property name="userDAO" ref="userDAO"></property> --> <constructor-arg ref="userDAO"></constructor-arg> </bean></beans>/Spring_IOC/test/yuki/spring/ioc/service/UserServiceTest.java
package yuki.spring.ioc.service;import org.junit.Test;//import org.springframework.beans.factory.BeanFactory;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import yuki.spring.ioc.pojo.User;public class UserServiceTest { @Test public void testAdd() { @SuppressWarnings("resource")// BeanFactory applicationContext = new ClassPathXmlApplicationContext("beans.xml"); ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml"); UserService userService = (UserService) applicationContext.getBean("userService"); User u = new User(); u.setUsername("username"); u.setPassword("password"); userService.add(u); }}运行结果如下：
八月 31, 2014 9:04:55 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3a439b: startup date [Sun Aug 31 09:04:55 CST 2014]; root of context hierarchy八月 31, 2014 9:04:55 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [beans.xml]6, gooduser saved...
控制反转：把具体的实现反转到了抽象的接口概念上；依赖注入：面向的是接口，注入它的实现
setter注入和构造方法注入，当有多个参数时可以定义索引或类型；可以把简单属性的值放在配置文件中，这很少用
2.Bean的生存范围、自动编织
bean的scope属性可以接受的字面值：singleton、prototype、request、session、global session、application
明显是和Web相关的，默认情况下是singleton
在添加XML Catalog Element后，在key后填写文件名在上下文环境中，取出相同的bean，它们指向同一个对象
在bean上添加属性scope="prototype"，prototype的意思是原型，取出来的对象是原型的复制品
如果bean是接收用户请求的action，scope应该设成prototype
/Spring_Scope/src/singleton.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-4.0.xsd "> <!-- <bean id="userService" class="yuki.spring.ioc.scope.singleton.UserService"></bean> --> <bean id="userService" class="yuki.spring.ioc.scope.UserService" scope="prototype"></bean></beans>/Spring_Scope/src/yuki/spring/ioc/scope/UserService.java
package yuki.spring.ioc.scope;public class UserService {}/Spring_Scope/src/yuki/spring/ioc/scope/ScopeTest.java
package yuki.spring.ioc.scope;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class ScopeTest { @Test public void testSingleton() { @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("singleton.xml"); UserService userService = (UserService) context.getBean("userService"); UserService userService2 = (UserService) context.getBean("userService"); System.out.println(userService == userService2); }}运行结果如下：
八月 31, 2014 9:34:53 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@265ba4: startup date [Sun Aug 31 09:34:53 CST 2014]; root of context hierarchy八月 31, 2014 9:34:54 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [singleton.xml]false
集合装配：set、list、map
/Spring_Scope/src/collections.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-4.0.xsd "> <bean id="userDao" class="yuki.spring.ioc.collections.UserDao"> <property name="sets"> <set> <value>1</value> <value>2</value> </set> </property> <property name="lists"> <list> <value>3</value> <value>4</value> <value>5</value> </list> </property> <property name="maps"> <map> <entry key="6" value="six"></entry> <entry key="7" value="seven"></entry> <entry key="8" value="eight"></entry> </map> </property> </bean></beans>/Spring_Scope/src/yuki/spring/ioc/collections/UserDao.java
package yuki.spring.ioc.collections;import java.util.List;import java.util.Map;import java.util.Set;public class UserDao { private Set<String> sets; private List<String> lists; private Map<String, String> maps; public Set<String> getSets() { return sets; } public void setSets(Set<String> sets) { this.sets = sets; } public List<String> getLists() { return lists; } public void setLists(List<String> lists) { this.lists = lists; } public Map<String, String> getMaps() { return maps; } public void setMaps(Map<String, String> maps) { this.maps = maps; } }/Spring_Scope/src/yuki/spring/ioc/collections/CollectionsTest.java
package yuki.spring.ioc.collections;import java.lang.reflect.Method;import java.util.List;import java.util.Map;import java.util.Set;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class CollectionsTest { @Test @SuppressWarnings("unchecked") public void testCollection() throws Exception{ @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("collections.xml"); UserDao userDao = (UserDao) context.getBean("userDao"); Method[] methods = userDao.getClass().getMethods(); for(Method method : methods){ switch(method.getName()){ case "getMaps": Map<String, String> map = (Map<String, String>) method.invoke(userDao, new Object[0]); for(Map.Entry<String, String> entry : map.entrySet()) System.out.println("map::" + entry.getKey() + " -> " + entry.getValue()); break; case "getSets": Set<String> set = (Set<String>) method.invoke(userDao, new Object[0]); for(String s : set) System.out.println("set::" + s); break; case "getLists": List<String> list = (List<String>) method.invoke(userDao, new Object[0]); for(String s : list) System.out.println("list::" + s); break; } } }}运行结果如下：
八月 31, 2014 9:36:12 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@265ba4: startup date [Sun Aug 31 09:36:12 CST 2014]; root of context hierarchy八月 31, 2014 9:36:12 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [collections.xml]set::1set::2map::6 -> sixmap::7 -> sevenmap::8 -> eightlist::3list::4list::5
autowire：autodetect、byName、byType、constructor、default、no
/Spring_Scope/src/yuki/spring/ioc/autowire/User.java
package yuki.spring.ioc.autowire;public class User {}
/Spring_Scope/src/yuki/spring/ioc/autowire/UserDAO.java
package yuki.spring.ioc.autowire;public interface UserDAO { void save(User user);}
/Spring_Scope/src/yuki/spring/ioc/autowire/UserDAOImpl.java
package yuki.spring.ioc.autowire;public class UserDAOImpl implements UserDAO { private int daoId; public int getDaoId() { return daoId; } public void setDaoId(int daoId) { this.daoId = daoId; } @Override public void save(User user) { System.out.println("user saved... " + daoId); }}
/Spring_Scope/src/yuki/spring/ioc/autowire/UserService.java
package yuki.spring.ioc.autowire;public class UserService { private UserDAO userDAO; public void setUserDAO(UserDAO userDAO) { this.userDAO = userDAO; } public void save(User user){ userDAO.save(user); }}
/Spring_Scope/src/autowire.xml
默认是no，意思是需要手动指定
<?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-4.0.xsd "> <bean id="userDAO" class="yuki.spring.ioc.autowire.UserDAOImpl"> <property name="daoId" value="1"></property> </bean> <bean id="userDAO2" class="yuki.spring.ioc.autowire.UserDAOImpl"> <property name="daoId" value="2"></property> </bean> <!-- <bean id="userService" class="yuki.spring.ioc.autowire.UserService" autowire="no"> <property name="userDAO" ref="userDAO1"></property> </bean> --> <bean id="userService" class="yuki.spring.ioc.autowire.UserService" autowire="byName"></bean> </beans>/Spring_Scope/src/autowire2.xml
default的意思是在beans标签内指定好了的
<?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-4.0.xsd " default-autowire="byType"> <bean id="userDAO" class="yuki.spring.ioc.autowire.UserDAOImpl"> <property name="daoId" value="2"></property> </bean> <bean id="userService" class="yuki.spring.ioc.autowire.UserService" autowire="byType"></bean> </beans>/Spring_Scope/src/yuki/spring/ioc/autowire/AutowireTest.java
package yuki.spring.ioc.autowire;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class AutowireTest { @Test public void testAutowire() throws Exception{ @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("autowire.xml"); UserService service = (UserService) context.getBean("userService"); service.save(new User()); } @Test public void testAutowire2() throws Exception{ @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("autowire2.xml"); UserService service = (UserService) context.getBean("userService"); service.save(new User()); }}运行结果如下：
八月 31, 2014 9:53:12 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@265ba4: startup date [Sun Aug 31 09:53:12 CST 2014]; root of context hierarchy八月 31, 2014 9:53:12 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [autowire.xml]user saved... 1八月 31, 2014 9:53:13 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1c0542: startup date [Sun Aug 31 09:53:13 CST 2014]; root of context hierarchy八月 31, 2014 9:53:13 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [autowire2.xml]user saved... 2
Bean的生命周期
如果不加lazy-init="true"，当new出ClassPathXmlApplicationContext时
配置文件里所有的bean就会初始化，beans里有标签属性default-lazy-init
设置为true后，bean在用的时候才会初始化
当应用启动起来非常慢时，可以设置lazy-init
ApplicationContext的接口里没有destroy方法
/Spring_Scope/src/yuki/spring/ioc/lifecycle/UserService.java
package yuki.spring.ioc.lifecycle;public class UserService { public void init(){ System.out.println("init"); } public void destroy(){ System.out.println("destroy"); } }/Spring_Scope/src/lifecycle.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-4.0.xsd"> <!-- <bean id="userService" class="yuki.spring.ioc.lifecycle.UserService" init-method="init" destroy-method="destroy" scope="prototype"></bean> --> <bean id="userService" class="yuki.spring.ioc.lifecycle.UserService" init-method="init" destroy-method="destroy"></bean> </beans>/Spring_Scope/src/yuki/spring/ioc/lifecycle/LifecycleTest.java
package yuki.spring.ioc.lifecycle;import org.springframework.context.support.ClassPathXmlApplicationContext;public class LifecycleTest { @SuppressWarnings({ "resource", "unused" }) public static void main(String[] args) { ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("lifecycle.xml"); UserService service = (UserService) context.getBean("userService"); UserService service2 = (UserService) context.getBean("userService"); // 这个方法在ApplicationContext的接口里没有 context.destroy(); }}运行结果如下：
八月 31, 2014 10:07:13 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@176fe71: startup date [Sun Aug 31 10:07:13 CST 2014]; root of context hierarchy八月 31, 2014 10:07:14 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [lifecycle.xml]init八月 31, 2014 10:07:14 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@176fe71: startup date [Sun Aug 31 10:07:13 CST 2014]; root of context hierarchydestroy
当bean的属性scope="prototype"时，上下文不再监测bean的destroy，所以不要和prototype一起用
作为一个数据源，需要close作为destroy-method方法
目录结构如下：
3.注解：自动编织，合格者
http://www.w3.org/2001/XMLSchema-instanceXML Schema instance namespacedtd文件或xsd文件可以称为元数据文件，xsd文件称为xml文件的schema<context:annotation-config></context:annotation-config>
它初始化了4个bean：
AutowiredAnnotationBeanPostProcessor,
处理bean初始化后的Autowired注解，默认byType
当有两个相同的要注入的类型时，就会匹配参数名，无法匹配就会报错
在preference>Java>Editor>Content> Assist>AutoActionAuto active triggers for Java 后添加@ 再输入@ 就会自动提示了qualifier - n.预选赛；（击败对手可进入某竞赛的）合格者；资格赛；外围赛建议写在setXxx方法上，也可以写在其它的方法上
For a fallback match, the bean name is considered a default qualifier value.
为了容错，bean的name默认是qualifier的值
CommonAnnotationBeanPostProcessor,
PersistenceAnnotationBeanPostProcessor,
RequiredAnnotationBeanPostProcessor,
the affected bean property must be populated at configuration time,
容错用的，初始化的时候必须注入进来
/Spring_Annotation/src/yuki/spring/annotation/autowired/User.java
package yuki.spring.annotation.autowired;public class User {}
/Spring_Annotation/src/yuki/spring/annotation/autowired/UserDAO.java
package yuki.spring.annotation.autowired;public interface UserDAO { void save(User user);}
/Spring_Annotation/src/yuki/spring/annotation/autowired/UserDAOImpl.java
package yuki.spring.annotation.autowired;public class UserDAOImpl implements UserDAO { @Override public void save(User user) { System.out.println("user saved... "); }}
/Spring_Annotation/src/yuki/spring/annotation/autowired/UserService.java
package yuki.spring.annotation.autowired;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Qualifier;public class UserService { private UserDAO userDAO; // 在容器里查找与参数对应类型的bean注入 @Autowired /*public void setUserDAO(UserDAO userDAO) { this.userDAO = userDAO; }*/ public void setUserDAO(@Qualifier("userDAO1") UserDAO userDAO) { this.userDAO = userDAO; } public void save(User user){ userDAO.save(user); }}/Spring_Annotation/src/annotation.xml
<?xml version="1.0" encoding="UTF-8"?><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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd "> <context:annotation-config></context:annotation-config> <bean id="userDAO1" class="yuki.spring.annotation.autowired.UserDAOImpl"></bean> <bean id="userDAO2" class="yuki.spring.annotation.autowired.UserDAOImpl"></bean> <bean id="userService" class="yuki.spring.annotation.autowired.UserService"></bean></beans>/Spring_Annotation/src/yuki/spring/annotation/autowired/AutowiredTest.java
package yuki.spring.annotation.autowired;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class AutowiredTest { @Test public void testAutowired() throws Exception{ @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("annotation.xml"); UserService service = (UserService) context.getBean("userService"); service.save(new User()); }}运行结果如下：
八月 31, 2014 10:28:40 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3a439b: startup date [Sun Aug 31 10:28:40 CST 2014]; root of context hierarchy八月 31, 2014 10:28:40 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [annotation.xml]user saved...
4.注解：资源，组件
JCP(Java Community Process)用来定义java的一些新的标准每一个标准可以成为一个JSR(Java Specification Request)@Resource表示引用了一个资源，默认是按名称，如果名称找不到，再按类型
填写属性name可以查找对应的bean的id并注入
/Spring_Annotation/src/yuki/spring/annotation/resource/UserDAO.java
package yuki.spring.annotation.resource;public interface UserDAO { void save();}
/Spring_Annotation/src/yuki/spring/annotation/resource/UserDAOImpl.java
package yuki.spring.annotation.resource;public class UserDAOImpl implements UserDAO { @Override public void save() { System.out.println("user saved... "); }}
/Spring_Annotation/src/yuki/spring/annotation/resource/UserService.java
package yuki.spring.annotation.resource;import javax.annotation.Resource;public class UserService { private UserDAO userDAO; // @Resource @Resource(name="userDAO2") public void setUserDAO(UserDAO userDAO) { this.userDAO = userDAO; } public void save(){ userDAO.save(); }}/Spring_Annotation/src/resource.xml
<?xml version="1.0" encoding="UTF-8"?><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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd "> <context:annotation-config></context:annotation-config> <bean id="userDAO" class="yuki.spring.annotation.resource.UserDAOImpl"></bean> <bean id="userDAO2" class="yuki.spring.annotation.resource.UserDAOImpl"></bean> <bean id="userService" class="yuki.spring.annotation.resource.UserService"></bean></beans>/Spring_Annotation/src/yuki/spring/annotation/resource/ResourceTest.java
package yuki.spring.annotation.resource;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class ResourceTest { @Test public void testAutowired() throws Exception{ @SuppressWarnings("resource") ApplicationContext context = new ClassPathXmlApplicationContext("resource.xml"); UserService service = (UserService) context.getBean("userService"); service.save(); }}运行结果如下：
八月 31, 2014 10:40:33 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3a439b: startup date [Sun Aug 31 10:40:33 CST 2014]; root of context hierarchy八月 31, 2014 10:40:33 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [resource.xml]user saved...
<context:component-scan base-package=""></context:component-scan>
在base-backage包下找bean，添加了注解Component的类
默认类名首字母小写作为bean的id，也可以填写value属性，作为bean的名称
/Spring_Annotation/src/yuki/spring/annotation/component/UserDAO.java
package yuki.spring.annotation.component;import org.springframework.stereotype.Component;@Component("u")public class UserDAO { public void save() { System.out.println("user saved... "); }}/Spring_Annotation/src/yuki/spring/annotation/component/UserService.java
package yuki.spring.annotation.component;import javax.annotation.PostConstruct;import javax.annotation.PreDestroy;import javax.annotation.Resource;import org.springframework.stereotype.Component;@Componentpublic class UserService { @PostConstruct public void init(){ System.out.println("init..."); } private UserDAO userDAO; @Resource(name="u") public void setUserDAO(UserDAO userDAO) { this.userDAO = userDAO; } public void save(){ userDAO.save(); } @PreDestroy public void destroy(){ System.out.println("destroy..."); }}/Spring_Annotation/src/component.xml
<?xml version="1.0" encoding="UTF-8"?><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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd "> <context:annotation-config></context:annotation-config> <context:component-scan base-package="yuki.spring.annotation.component"></context:component-scan> </beans>/Spring_Annotation/src/yuki/spring/annotation/component/ComponentTest.java
package yuki.spring.annotation.component;import org.junit.Test;import org.springframework.context.support.ClassPathXmlApplicationContext;public class ComponentTest { @Test public void testAutowired() throws Exception{ @SuppressWarnings("resource") ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("component.xml"); UserService service = (UserService) context.getBean("userService"); service.save(); context.destroy(); }}运行结果如下：
八月 31, 2014 10:47:26 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3a439b: startup date [Sun Aug 31 10:47:26 CST 2014]; root of context hierarchy八月 31, 2014 10:47:26 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [component.xml]init...user saved... 八月 31, 2014 10:47:27 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@3a439b: startup date [Sun Aug 31 10:47:26 CST 2014]; root of context hierarchydestroy...
By default, classes annotated with @Component, @Repository, @Service, @Controller,
or a custom annotation that itself is annotated with @Component are the only detected candidate components.
默认被这四个注解所注解的类被认为是组件
生存范围： @Scope(BeanDefinition.SCOPE_SINGLETON)放在类的定义之前
PostConstruct和PreDestroy，相当于init和的destroy
目录结构如下：
本文参考了[尚学堂马士兵_Spring_IOC]的公开课程
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kongdongyang
2014/8/31
Spring依赖注入 --- 简单使用说明
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