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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!
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, good user 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::1 set::2 map::6 -> six map::7 -> seven map::8 -> eight list::3 list::4 list::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 hierarchy destroy
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-instance
XML Schema instance namespace
dtd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>AutoAction
Auto 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;
@Component
public 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 hierarchy destroy...
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
更多好文请关注:http://www.cnblogs.com/kodoyang/
kongdongyang
2014/8/31
标签:des style blog http color os 使用 io java
原文地址:http://www.cnblogs.com/kodoyang/p/Frame_Spring_IOC_Tutorial.html