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。