Hello World
HelloWorld.java
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | package com.test.spring01; public class HelloWorld { private String name; public HelloWorld() { System.out.println( "调用构造函数..." ); } public String getName() { return name; } public void setName2(String name) { //对应name="name2" this .name = name; } public void sayHello() { System.out.println( "Hello," + name); } } |
Main.java
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | package com.test.spring01; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) { //ClassPathXmlApplicationContext是ApplicationContext接口的实现类，实现从类路径下加载配置文件 ApplicationContext applicationContext = new ClassPathXmlApplicationContext( "ApplicationContext.xml" ); System.out.println( "创建对象" ); HelloWorld helloWorld = (HelloWorld)applicationContext.getBean( "a1" ); //HelloWorld helloWorld = applicationContext.getBean(HelloWorld.class); //这种方式要求在配置文件中只配置了一个HelloWorld的bean helloWorld.sayHello(); } } |
applicationContext.xml
| 1 2 3 4 5 6 7 8 9 10 11 12 | <? 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-3.0.xsd"> < bean id = "a1" class = "com.test.spring01.HelloWorld" > < property name = "name2" value = "spring" /> <!--set方法注入--> </ bean > </ beans > |
运行结果
调用构造函数...
创建对象
Hello,spring
也可以通过构造方法注入
| 1 2 3 4 5 6 | <!--通过构造方法来配置bean属性--> < bean id = "car" class = "com.atguigu.spring.beans.Car" > <!--参数和构造函数的参数对应--> < constructor-arg value = "Audi" index = "0" ></ constructor-arg > < constructor-arg value = "Shanghai" index = "1" ></ constructor-arg > < constructor-arg value = "300000" type = "double" ></ constructor-arg > </ bean > |
| 1 2 3 4 5 6 | <!--使用构造器注入属性值可以指定参数的位置和参数的类型，以区分重载的构造器--> < bean id = "car2" class = "com.atguigu.spring.beans.Car" > < constructor-arg value = "Baoma" type = "java.lang.String" ></ constructor-arg > < constructor-arg value = "Shanghai" type = "java.lang.String" ></ constructor-arg > < constructor-arg value = "400000" type = "int" ></ constructor-arg > </ bean > |
有特殊标记时也可以下面这么写
| 1 2 3 4 5 6 7 8 9 | < bean id = "car2" class = "com.atguigu.spring.beans.Car" > < constructor-arg value = "Baoma" type = "java.lang.String" ></ constructor-arg > < constructor-arg type = "java.lang.String" > < value > <![CDATA[<Shanghai^>]]> </ value > </ constructor-arg > < constructor-arg type = "int" > < value >400000</ value > </ constructor-arg > </ bean > |
引用类型
| 1 2 3 4 5 | < bean id = "person" class = "com.atguigu.spring.beans.Person" > < property name = "name" value = "Tom" ></ property > < property name = "age" value = "34" ></ property > < property name = "car" ref = "car2" ></ property > <!--引用car2--> </ bean > |
内部bean，不能被外部引用，只能在内部使用
| 1 2 3 4 5 6 7 8 | <!--内部bean--> < property name = "car" > <!--上面的car可以这么写--> < bean class = "com.atguigu.spring.beans.Car" > < constructor-arg value = "Ford" ></ constructor-arg > < constructor-arg value = "Changan" ></ constructor-arg > < constructor-arg value = "200000" type = "double" ></ constructor-arg > </ bean > </ property > |
赋null值
| 1 2 | <!--测试值赋null--> < constructor-arg >< null /></ constructor-arg > |
为级联属性赋值（必须有set方法） 要先创建car才能赋值
| 1 2 3 | < constructor-arg ref = "car" ></ constructor-arg > <!--为级联属性赋值--> < property name = "car.macSpeed" value = "240" ></ property > |
为集合属性赋值（list set map）
| 1 2 3 4 5 6 7 8 9 10 | < bean id = "person3" class = "com.atguigu.spring.collections.Person" > < property name = "name" value = "Tom" ></ property > < property name = "age" value = "34" ></ property > < property name = "cars" > <!--cars是Person类的一个list类型的属性--> < list > < ref bean = "car" > < ref bean = "car2" > </ list > </ property > </ bean > |
| 1 2 3 4 5 6 7 8 9 10 11 | <!--配置Map属性值--> < bean id = "person4" class = "com.atguigu.spring.collections.Person" > < property name = "name" value = "Tom" ></ property > < property name = "age" value = "34" ></ property > < property name = "cars" > <!--cars是Person类的一个map类型的属性--> < map > < entry key = "AA" value-ref = "car" ></ entry > < entry key = "BB" value-ref = "car2" ></ entry > </ map > </ property > </ bean > |
| 1 2 3 4 5 6 7 8 9 10 11 | <!--配置Peoperties属性值--> < bean id = "dataSource" class = "com.atguigu.spring.collections.dataSource" > < property name = "peoperties" > < props > < prop key = "user" >root</ prop > < prop key = "password" >123456</ prop > < prop key = "jdbcUrl" >jdbc:mysql:///test</ prop > < prop key = "driverClass" >com.mysql.jdbc.Driver</ prop > </ props > </ property > </ bean > |
| 1 2 3 4 5 6 7 8 9 10 | <!--配置单例的集合bean，以供多个bean进行引用，需要导入util命名空间--> < util:list id = "cars" > < ref bean = "car" > < ref bean = "car2" > </ util:list > < bean id = "person4" class = "com.atguigu.spring.collections.Person" > < property name = "name" value = "Jack" ></ property > < property name = "age" value = "29" ></ property > < property name = "cars" ref = "cars" ></ property > <!--引用上面配置的cars--> </ bean > |
| 1 2 3 | <!--通过P命名空间为bean的属性赋值，需要先导入P命名空间--> < bean id = "person5" class = "com.atguigu.spring.collections.Person" p:age = "35" p:name = "Shang" p:cars-ref = "cars" > </ bean > |
自动装配（Person类中有address属性和car属性）
byName根据bean的名字和当前bean的setter风格的属性名进行自动装配。
byType根据bean的类型和当前bean的数学的类型进行自动装配。（如果有两个类型一样的bean就会出错）
缺点：在bean配置文件里设置autowire属性进行自动装配将会装配bean的所有属性。若只希望装配个别属性时，autowire属性就不够灵活了。autowire属性要么根据类型自动装配，要么根据名称自动装配，不能两者兼而有之。
一般情况下，在是寄到 项目中很少使用自动装配功能，因为和自动装配功能所带来的好处比起来，明确清晰的配置文档更有说服力一些。
| 1 2 3 4 5 | < bean id = "address" class = "com.atguigu.spring.beans.autowire.Address" p:city = "Beijing" p:street = "Huilongguan" ></ bean > < bean id = "car" class = "com.atguigu.spring.beans.autowire.Car" p:brand = "Audi" p:price = "30000" ></ bean > < bean id = "person" class = "com.atguigu.spring.beans.autowire.Person" p:name = "Tom" p:autowire = "byName" ></ bean > |
bean配置的继承
| 1 2 3 4 | < bean id = "address" class = "com.atguigu.spring.beans.autowire.Address" p:city = "Beijing" p:street = "Wudaokou" > </ bean > <!--bean配置的继承：使用bean的parent属性指定继承哪个bean的配置--> < bean id = "address2" p:street = "Dazhongsi" parent = "address" ></ bean > |
抽象bean，只能被继承
| 1 2 3 4 | <!--抽象bean：bean的abstract属性为true的bean，不能被IOC容器实例化 若一个bean的class属性没有指定，则该bean必须是一个抽象的bean。类似抽象类 --> < bean id = "address" p:city = "Beijing" p:street = "Wudaokou" abstract = "true" ></ bean > |
bean之间的依赖关系
Spring允许用户通过depends-on属性设定Bean前置依赖的Bean，前置依赖的Bean会在本Bean实例化之前创建好。如果前置依赖于多个Bean，则可以通过逗号、空格的方式配置多个Bean。
| 1 2 3 | < bean id = "car" class = "com.atguigu.spring.autowire.Car" p:brand = "Audi" p:price = "30000" ></ bean > <!--要求在配置person时，必须有一个关联的car。person这个bean依赖于car这个bean--> < bean id = "person" class = "som.atguigu.spring.beans.autowire.Person" p:name = "Tom" p:address-ref = "address2" depends-on = "car" ></ bean > |
bean配置的作用域
默认为单例singleton，容器初始化时创建bean实例，在整个容器的生命周期里只创建一个bean。
prototype原型，容器初始化时不创建bean实例，在每次请求时创建一个新的bean实例并返回。
| 1 2 3 4 | < bean id = "car" class = "com.atguigu.spring.autowire.Car" scope = "prototype" > < property name = "brand" value = "Audi" ></ property > < property name = "price" value = "300000" ></ property > </ bean > |
引入外部配置文件
不引入配置文件时这么写. beans-properties.xml
| 1 2 3 4 5 6 | < bean id = "dataSource" class = "com.mchange.v2.c3p0.ComboPooledDataSource" > < property name = "user" value = "root" ></ property > < property name = "password" value = "123456" ></ property > < property name = "driverClass" value = "com.mysql.jdbc.Driver" ></ property > < property name = "jdbcUrl" value = "jdbc:mysql:///test" ></ property > </ bean > |
| 1 2 3 | ApplicationContext ctx = new ClassPathXmlApplicationContext( "beans-properties.xml" ); DataSource dataSource = (DataSource)ctx.getBean( "dataSource" ); System.out.println(dataSource.getConnection()); //建立连接 |
引入外部配置文件
db.properties
| 1 2 3 4 | user=root password= 123456 driverClass=com.mysql.jdbc.Driver jdbcUrl=jdbc:mysql: ///test |
beans-properties.xml写法
| 1 2 3 4 5 6 7 8 | <!--导入属性文件--> <!--要导入context命名空间--> < context:property-placeholder location = "classpath:db.properties" /> < bean id = "dataSource" class = "com.mchange.v2.c3p0.ComboPooledDataSource" > < property name = "user" value = "${user}" ></ property > < property name = "password" value = "${password}" ></ property > < property name = "driverClass" value = "${driverClass}" ></ property > < property name = "jdbcUrl" value = "${jdbcUrl}" ></ property > </ bean > |
Spring表达式语言：SpEL。支持运行时查询和操作对象。
字面量的表示
整数
| 1 | < property name = "count" value = "#{5}" /> |
小数
| 1 | < property name = "frequency" value = "#{89.7}" /> |
科学计数法
| 1 | < property name = "capacity" value = "1e4" /> |
String可以使用单引号或者双引号作为字符串的定界符号
| 1 2 | < property name = "name" value = "#{'chuck'}" /> < property name = "name" value = '#{"chuck"}' /> |
Boolean
| 1 | < property name = "enabled" value = "#{false}" /> |
引用其他对象，等同ref
| 1 2 | <!--通过value属性和SpEL配置bean之间的引用关系--> < property name = "prefix" value = "#{prefixGernerator}" /> |
引用其他对象的属性
| 1 | < property name = "suffix" value = "#{prefixGernerator.suffix}" /> |
调用其他方法，还可以链式操作
| 1 | < property name = "suffix" value = "#{prefixGernerator.toString()}" /> |
| 1 2 | <!---方法的连缀--> < property name = "suffix" value = "#{prefixGernerator.toString().toUpperCase()}" /> |
| 1 | < property name = "price" value = "#{T(java.jang.Math).PI*80}" ></ property > |
| 1 2 3 4 5 6 | <!--使用SpEL表达式来引用其他的bean--> < property name = "car" value = "#{car}" ></ property > <!--使用SpEL表达式来引用其他的bean的属性--> < property name = "city" value = "#{address.city}" ></ property > <!--在SpEL中使用运算符--> < property name = "info" value="#{car.price>300000?'金玲':'白领'}"></ property > |
为bean指定init方法和destroy方法
| 1 2 3 4 5 | < bean id = "car" class = "com.atguigu.spring.bean.Car" init-method = "init" destroy-method = "destroy" > <!--init和destroy对应Car类中的init destroy方法--> < property name = "brand" value = "Audi" ></ property > </ bean > <!--setBrand之后调用init方法，ctx.close();时调用destroy方法--> |
Bean后置处理器允许在调用初始化方法前后对bean进行额外的处理。Bean后置处理器对IOC容器里的所有的Bean实例逐一处理，而非单一实例。其典型应用是：检查Bean属性的正确性或根据特定的标准更改Bean属性。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | public class MyBeanPostProcessor implements BeanPostProcessor{ //处理所有bean @override public Object postProcessBeforeInitialization(Object bean, Stirng beanName) throws BeansException{ //可以在这里进行一些操作 if ( "car" .equals(beanName)){ //... } System.out.println( "postProcessBeforeInitialization..." ); return bean; } @override public Object postProcessAfterInitialization(Object bean, Stirng beanName) throws BeansException{ System.out.println( "postProcessAfterInitialization..." ); //可以在这里对bean的属性进行更改...安全隐患 return bean; } } |
| 1 2 3 4 5 6 7 8 9 10 | <!--配置文件中配置bean的后置处理器。不需要配置id，IOC容器自动识别是一个BeanPostProcessor--> <!-- 实现BeanPostProcessor接口，并且提供实现 Object postProcessBeforeInitialization(Object bean, Stirng beanName) init-method之前调用 Object postProcessAfterInitialization(Object bean, Stirng beanName) init-method之后调用 bean: bean实例本身 beanName：IOC容器配置的bwan的名字 返回值：实际上返回给用户的bean。可以在以上两个方法中修改返回的bean，甚至返回一个新的bean --> < bean class = "com.atguigu.spring.MyBeanPostProcessor" ></ bean > |
Spring IOC容器对Bean的生命周期进行管理的过程
-通过构造器或工厂方法创建Bean实例
-为bean的属性设置值和对其他bean的引用
-将bean实例传递给bean后置处理器的postProcessBeforeInitialization方法
-调用bean的初始化方法
-将bean实例传递给bean后置处理器的postProcessAfterInitialization方法
-bean可以使用了
-容器关闭时，调用bean的销毁方法
静态工厂方法
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 | /** *静态工厂方法：直接调用某一个类的静态方法就可以返回bean的实例 */ public class StaticCarFactory{ private static Map<String, car> cars = new HashMap<String, Car>(); static { cars.put( "audi" , new Car( "audi" , 300000 )); cars.put( "ford" , new Car( "ford" , 400000 )); } //静态工厂方法 public static Car getCar(String name){ return cars.get(name); } } |
| 1 2 3 4 5 6 7 8 9 10 11 | <!--通过静态工厂方法来配置bean--> <!-- class属性：指向静态工程方法的全类名 factory-method:静态工厂方法的名字 constructor-arg:如果工厂方法需要传入参数，使用constructor-arg来配置参数 --> < bean id = "car1" class = "com.atguigu.spring.StaticCarFactory" factory-method = "getCar" > < constructor-arg value = "audi" ></ constructor-arg > </ bean > |
| 1 | Car car = (Car)ctx.getBean( "car1" ); //取对象 |
实例工厂方法
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | /** *实例工厂方法，即先需要创建工厂，然后调用工厂的实例方法来返回bean的实例 */ public class InstanceCarFactory{ private Map<String, car> cars = null ; public InstanceCarFactory(){ cars = new HashMap<String, Car>(); cars.put( "audi" , new Car( "audi" , 300000 )); cars.put( "ford" , new Car( "ford" , 400000 )); } public Car getCar(String name){ return cars.get(name); } } |
| 1 2 3 4 5 6 7 8 9 10 | < bean id = "carFactory" class = "com.atguigu.spring.InstanceCarFactory" ></ bean > <!--通过实例工厂方法来配置bean--> <!-- factory-bean属性：指向实例工程方法的全类名 factory-method:方法的名字 constructor-arg:如果工厂方法需要传入参数，使用constructor-arg来配置参数 --> < bean id = "car2" factory-bean = "carFactory" factory-method = "getCar" > < constructor-arg value = "audi" ></ constructor-arg > </ bean > |
| 1 | Car car = (Car)ctx.getBean( "car2" ); //取对象 |
通过FactoryBean配置Bean
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | public class CarFactoryBean implements FactoryBean{ private String name; public String getName() { return name; } public void setName(String name) { this .name = name; } @Override public Object getObject() throws Exception { return new Car(name, "beijing" ); //调用构造函数 } @Override public Class getObjectType() { return Car. class ; } @Override public boolean isSingleton() { return true ; } } |
| 1 2 3 | < bean id = "car" class = "com.test.spring04.CarFactoryBean" > < property name = "name" value = "BMW" ></ property > </ bean > |
| 1 2 | Car car = (Car) applicationContext.getBean( "car" ); System.out.println(car); |
在IOC容器中通过注解配置Bean
组件扫描（component scanning）：Spring可以从classpath下自动扫描、侦测和实例化具有特定注解的组件。
特定组件包括：
-@Component 基本注解，标识了一个受Spring管理的组件
-@Repository 标识持久层组件
-@Service 标识服务层（业务层）组件
-@Controller 标识表现层组件
对于扫描到的组件，Spring有默认的莫名策略：使用非限定类名，第一个字母小写，也可以在注解中通过value属性值标识组件的名称。