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spring 学习1

2016-05-11 1283

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简介：

1. spring is lightweight= minimal impact

2. Spring DI= JavaBeans +interfaces

3.JSR-330=Dependency Injection for Java

4.JSR-303= Bean Validation API specification

     Java代码  
     
   
props = new Properties();  
props.load(new FileInputStream(“ch2/src/conf/msf.properties”));  
String rendererClass = props.getProperty(“renderer.class”);   

6.Injection vs. Lookup

7.<context:annotation-config>tag tells Spring to scan the codebase for dependency requirements.because of <context:annotation-config>tag, during the initialization of Spring’s ApplicationContext, Spring will discover those @Autowired annotations and inject the dependency (discovered via the <context:component-scan>tag) as required.

@Value("John Smith")

private String name;

9.SpringEL

     Java代码  
     
   
public class InjectSimpleConfig {   
private String name = "John Smith";   
private int age = 35;   
private float height = 1.78f;   
private boolean programmer = true;   
private Long ageInSeconds = 1103760000L;   
// Getter/setter method omitted   
}   

     Xml代码  
     
   
<bean id="injectSimpleConfig" class="com.apress.prospring3.ch4.xml.InjectSimpleConfig"/>   
<bean id="injectSimpleSpel" class="com.apress.prospring3.ch4.xml.InjectSimpleSpel">   
<property name="name">   
<value>#{injectSimpleConfig.name}</value>   
</property>   
<property name="age">   
<value>#{injectSimpleConfig.age + 1}</value>   
</property>   
<property name="height">   
<value>#{injectSimpleConfig.height}</value>   
</property>   
<property name="isProgrammer">   
<value>#{injectSimpleConfig.programmer}</value>   
</property>   
<property name="ageInSeconds">   
<value>#{injectSimpleConfig.ageInSeconds}</value>   
</property>   
</bean>   

     Java代码  
     
   
@Service("injectSimpleSpel")   
public class InjectSimpleSpel {   
@Value("#{injectSimpleConfig.name}")   
private String name;   
@Value("#{injectSimpleConfig.age + 1}")   
private int age;   
@Value("#{injectSimpleConfig.height}")   
private float height;   
@Value("#{injectSimpleConfig.programmer}")   
private boolean programmer;   
@Value("#{injectSimpleConfig.ageInSeconds}")   
private Long ageInSeconds;   
// Other codes omitted   
}   

10. Using Collections for Injection

     Java代码  
     
   
public class CollectionInjection {   
private Map<String, Object> map;   
private Properties props;   
private Set set;   
private List list;   
public static void main(String[] args) {   
GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();   
ctx.load("classpath:app-context-xml.xml");   
ctx.refresh();   
CollectionInjection instance = (CollectionInjection) ctx.getBean("injectCollection");   
instance.displayInfo();   
}   
public void setList(List list) {   
this.list = list;   
}   
public void setSet(Set set) {   
this.set = set;   
}   
public void setMap(Map <String, Object> map) {   
this.map = map;   
}   
public void setProps(Properties props) {   
this.props = props;   
}   
public void displayInfo() {   
// display the Map   
System.out.println("Map contents:\n");   
for (Map.Entry<String, Object> entry: map.entrySet()) {   
System.out.println("Key: " + entry.getKey() + " - Value: " + entry.getValue());   
}   
// display the properties   
System.out.println("\nProperties contents:\n");   
for (Map.Entry<Object, Object> entry: props.entrySet()) {   
System.out.println("Key: " + entry.getKey() + " - Value: " + entry.getValue());   
}   
// display the set   
System.out.println("\nSet contents:\n");   
for (Object obj: set) {   
System.out.println("Value: " + obj);   
}   
// display the list   
System.out.println("\nList contents:\n");   
for (Object obj: list) {   
System.out.println("Value: " + obj);   
}   
}   
}   

     Java代码  
     
   
<bean id="oracle" name="wiseworm" class="com.apress.prospring3.ch4.BookwormOracle"/>   
<bean id="injectCollection" class="com.apress.prospring3.ch4.xml.CollectionInjection">   
<property name="map">   
<map>   
<entry key="someValue">   
<value>Hello World!</value>   
</entry>   
<entry key="someBean">   
<ref local="oracle"/>   
</entry>   
</map>   
</property>   
<property name="props">   
<props>   
<prop key="firstName">Clarence</prop>   
<prop key="secondName">Ho</prop>   
</props>   
</property>   
<property name="set">   
<set>   
<value>Hello World!</value>   
<ref local="oracle"/>   
</set>   
</property>   
<property name="list">   
<list>   
<value>Hello World!</value>   
<ref local="oracle"/>   
</list>   
</property>   
</bean>   

////////////////////////////////////////////////////////////////////////////////////////////////////////////

     Xml代码  
     
   
<util:map id="map" map-class="java.util.HashMap">   
<entry key="someValue">   
<value>Hello World!</value>   
</entry>   
<entry key="someBean">   
<ref bean="oracle"/>   
</entry>   
</util:map>   
<util:properties id="props">   
<prop key="firstName">Clarence</prop>   
<prop key="secondName">Ho</prop>   
</util:properties>   
<util:set id="set">   
<value>Hello World!</value>   
<ref bean="oracle"/>   
</util:set>   
<util:list id="list">   
<value>Hello World!</value>   
<ref bean="oracle"/>   
</util:list>  

     Java代码  
     
   
@Service("injectCollection")   
public class CollectionInjection {   
@Resource(name="map")   
private Map<String, Object> map;   
@Resource(name="props")   
private Properties props;   
@Resource(name="set")   
private Set set;   
@Resource(name="list")   
private List list;   
// Other codes omitted   
}   

11.Bean Scopes

Singleton:The default singleton scope.

Prototype:A new instance will be created by Spring when requested by application.

Request:For web application use. When using Spring MVC for web application,

beans with request scope will be instantiated for every HTTP request and then

destroyed when the request is completed.

Session:For web application use. When using Spring MVC for web applications,

beans with session scope will be instantiated for every HTTP session and then

destroyed when the session is over.

Global session:For portlet-based web applications. The global session scope beans

can be shared among all portlets withinthe same Spring MVC–powered portal

application.

Thread: A new bean instance will be created by Spring when requested by a new

thread, while for the same thread, the same bean instance will be returned. Note

that this scope is not registered by default.

Custom:Custom bean scope that can be created by implementing the interface

org.springframework.beans.factory.config.Scopeand registering the custom

scope in Spring’s configuration (for XML, use the class org.springframework.beans

.factory.config.CustomScopeConfigurer).

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