Spring 配置使用介绍

一、集合类型注入

1、注解形式

package com.apress.prospring5.ch3.annotated;import com.apress.prospring5.ch3.ContentHolder;
import org.springframework.stereotype.Service;/*** Created by iuliana.cosmina on 2/19/17.*/
@Service("lyricHolder")
public class LyricHolder implements ContentHolder{private String value = "'You be the DJ, I'll be the driver'";@Override public String toString() {return "LyricHolder: { " + value + "}";}
}

package com.luo.spring.guides.iocdi.collections.annotation;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;@Service("injectCollection")
public class CollectionInjection {/***      @Resource(name="map") is equivalent with @Autowired @Qualifier("map")*/@Autowired@Qualifier("map")private Map<String, Object> map;@Resource(name="props")private Properties props;@Resource(name="set")private Set set;@Resource(name="list")private List list;public void displayInfo() {System.out.println("Map contents:\n");map.entrySet().stream().forEach(e -> System.out.println("Key: " + e.getKey() + " - Value: " + e.getValue()));System.out.println("\nProperties contents:\n");props.entrySet().stream().forEach(e -> System.out.println("Key: " + e.getKey() + " - Value: " + e.getValue()));System.out.println("\nSet contents:\n");set.forEach(obj -> System.out.println("Value: " + obj));System.out.println("\nList contents:\n");list.forEach(obj -> System.out.println("Value: " + obj));}}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xmlns:util="http://www.springframework.org/schema/util"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/utilhttp://www.springframework.org/schema/util/spring-util.xsd"><context:component-scan base-package="com.apress.prospring5.ch3.annotated"/><util:map id="map" map-class="java.util.HashMap"><entry key="someValue" value="It's a Friday, we finally made it"/><entry key="someBean" value-ref="lyricHolder"/></util:map><util:properties id="props"><prop key="firstName">John</prop><prop key="secondName">Mayer</prop></util:properties><util:set id="set" set-class="java.util.HashSet"><value>I can't believe I get to see your face</value><ref bean="lyricHolder"/></util:set>	<util:list id="list" list-class="java.util.ArrayList"><value>You've been working and I've been waiting</value><ref bean="lyricHolder"/></util:list>
</beans>

测试

package com.luo.spring.guides.iocdi.collections.annotation;import com.luo.spring.guides.iocdi.annotation.setter.SetterInjectionConfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 17:41* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/collections/app-context-annotation.xml");ctx.refresh();CollectionInjection instance = (CollectionInjection) ctx.getBean("injectCollection");instance.displayInfo();ctx.close();}
}

输出

Map contents:

Key: map - Value: {someBean=LyricHolder: { ‘You be the DJ, I’ll be the driver’}, someValue=It’s a Friday, we finally made it}

Properties contents:

Key: firstName - Value: John
Key: secondName - Value: Mayer

Set contents:

Value: LyricHolder: { ‘You be the DJ, I’ll be the driver’}
Value: I can’t believe I get to see your face

List contents:

Value: You’ve been working and I’ve been waiting
Value: LyricHolder: { ‘You be the DJ, I’ll be the driver’}

2、xml 形式

package com.luo.spring.guides.iocdi.collections;public interface ContentHolder {}

package com.luo.spring.guides.iocdi.collections;/*** Created by iuliana.cosmina on 2/19/17.*/
public class LyricHolder implements ContentHolder{private String value = "'You be the DJ, I'll be the driver'";@Override public String toString() {return "LyricHolder: { " + value + "}";}
}

package com.luo.spring.guides.iocdi.collections;import org.springframework.context.support.GenericXmlApplicationContext;import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;public class CollectionInjection {private Map<String, Object> map;private Properties props;private Set set;private List list;public void displayInfo() {System.out.println("Map contents:\n");map.entrySet().stream().forEach(e -> System.out.println("Key: " + e.getKey() + " - Value: " + e.getValue()));System.out.println("\nProperties contents:\n");props.entrySet().stream().forEach(e -> System.out.println("Key: " + e.getKey() + " - Value: " + e.getValue()));System.out.println("\nSet contents:\n");set.forEach(obj -> System.out.println("Value: " + obj));System.out.println("\nList contents:\n");list.forEach(obj -> System.out.println("Value: " + obj));}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;}
}

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="lyricHolder" class="com.luo.spring.guides.iocdi.collections.LyricHolder"/><bean id="injectCollection" class="com.luo.spring.guides.iocdi.collections.CollectionInjection"><property name="map"><map><entry key="someValue" value="It's a Friday, we finally made it"/><entry key="someBean" value-ref="lyricHolder"/></map></property><property name="props"><props><prop key="firstName">John</prop><prop key="secondName">Mayer</prop></props></property><property name="set"><set><value>I can't believe I get to see your face</value><ref bean="lyricHolder"/></set></property><property name="list"><list><value>You've been working and I've been waiting</value><ref bean="lyricHolder"/></list></property></bean>
</beans>

测试

package com.luo.spring.guides.iocdi.collections;import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 17:27* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/collections/app-context-xml.xml");ctx.refresh();CollectionInjection instance = (CollectionInjection) ctx.getBean("injectCollection");instance.displayInfo();ctx.close();}
}

输出

Map contents:

Key: someValue - Value: It’s a Friday, we finally made it
Key: someBean - Value: LyricHolder: { ‘You be the DJ, I’ll be the driver’}

Properties contents:

Key: firstName - Value: John
Key: secondName - Value: Mayer

Set contents:

Value: I can’t believe I get to see your face
Value: LyricHolder: { ‘You be the DJ, I’ll be the driver’}

List contents:

Value: You’ve been working and I’ve been waiting
Value: LyricHolder: { ‘You be the DJ, I’ll be the driver’}

二、alias 使用

1、xml 形式

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="john" name="jon johnny,jonathan;jim" class="java.lang.String"/><alias name="john" alias="ion"/><bean name="jon1 johnny1,jonathan1;jim1" class="java.lang.String"/><bean id="jon1 johnny1,jonathan1;jim1" class="java.lang.String"/>
</beans>

测试

package com.luo.spring.guides.iocdi.alias;import org.springframework.context.support.GenericXmlApplicationContext;import java.util.Arrays;
import java.util.Map;/*** @author : archer* @date : Created in 2022/11/30 19:09* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/alias/app-context-alias.xml");ctx.refresh();String s1 = (String) ctx.getBean("john");String s2 = (String) ctx.getBean("jon");String s3 = (String) ctx.getBean("johnny");String s4 = (String) ctx.getBean("jonathan");String s5 = (String) ctx.getBean("jim");String s6 = (String) ctx.getBean("ion");System.out.println((s1 == s2));System.out.println((s2 == s3));System.out.println((s3 == s4));System.out.println((s4 == s5));System.out.println((s5 == s6));Map<String,String> beans = ctx.getBeansOfType(String.class);if(beans.size() == 3) {System.out.println("There is only 3 String bean.");}beans.entrySet().stream().forEach(b ->System.out.println("id: " + b.getKey() + "\n aliases: "+ Arrays.toString(ctx.getAliases(b.getKey())) + "\n"));ctx.close();}
}

输出

true
true
true
true
true

id: john
aliases: [jon, ion, jonathan, jim, johnny]

id: jon1
aliases: [jonathan1, johnny1, jim1]

id: jon1 johnny1,jonathan1;jim1
aliases: []

2、注解形式

package com.luo.spring.guides.iocdi.alias.annotation;import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;/*** Created by iuliana.cosmina on 2/19/17.** Observation: @Component("singer") is equivalent to @Component in this case* Decomment and comment annotations below and test the result.*/
@Component("johnMayer")
public class Singer {private String lyric = "We found a message in a bottle we were drinking";public void setLyric(@Value("I'm busted up but I'm loving every minute of it")String lyric) {this.lyric = lyric;}public void sing() {System.out.println(lyric);}}

package com.luo.spring.guides.iocdi.alias.annotation;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** @author : archer* @date : Created in 2022/11/30 19:19* @description :*/
public class AliasConfig {@Configurationstatic class AliasBeanConfig {@Bean(name = {"johnMayer", "john", "jonathan", "johnny"})public Singer singer() {return new Singer();}}
}

测试

package com.luo.spring.guides.iocdi.alias.annotation;import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.GenericApplicationContext;import java.util.Arrays;
import java.util.Map;/*** @author : archer* @date : Created in 2022/11/30 19:19* @description :*/
public class Main {public static void main(String... args) {GenericApplicationContext ctx = new AnnotationConfigApplicationContext(AliasConfig.AliasBeanConfig.class);Map<String, Singer> beans = ctx.getBeansOfType(Singer.class);beans.entrySet().stream().forEach(b ->System.out.println("id: " + b.getKey() + "\n aliases: "+ Arrays.toString(ctx.getAliases(b.getKey())) + "\n"));ctx.close();}
}

输出

id: johnMayer
aliases: [jonathan, johnny, john]

三、depends-on

package com.luo.spring.guides.iocdi.dependson.domain;import org.springframework.stereotype.Component;/*** Created by iuliana.cosmina on 2/22/17.*/
@Component("gopher")
public class Guitar {public void sing(){System.out.println("Cm Eb Fm Ab Bb");}
}

package com.luo.spring.guides.iocdi.dependson.domain;import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.DependsOn;
import org.springframework.stereotype.Component;/*** Created by iuliana.cosmina on 2/22/17.*/
@Component("johnMayer")
@DependsOn("gopher")
public class Singer implements ApplicationContextAware{ApplicationContext applicationContext;@Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}private Guitar guitar;public Singer(){}public void sing() {guitar =  applicationContext.getBean("gopher",Guitar.class);guitar.sing();}
}

1、xml 形式

• 表明实例 gopher 必须在实例 johnMayer 之前初始化，用于控制 Spring 实例化 bean 的顺序。

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- Following the principle of DRY (Don't Repeat Yourself) the same classes can be used for the XMLand Annotated example. If component scanning is not enabled, the annotations are ignored. --><bean id="johnMayer" class="com.luo.spring.guides.iocdi.dependson.domain.Singer" depends-on="gopher"/><bean id="gopher" class="com.luo.spring.guides.iocdi.dependson.domain.Guitar"/>
</beans>

测试

package com.luo.spring.guides.iocdi.dependson.xml;import com.luo.spring.guides.iocdi.dependson.domain.Singer;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 19:29* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("iocdi/injection/dependson/app-context-xml.xml");ctx.refresh();Singer johnMayer = ctx.getBean("johnMayer", Singer.class);johnMayer.sing();ctx.close();}
}

输出

Cm Eb Fm Ab Bb

2、注解形式

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd"><context:component-scanbase-package="com.luo.spring.guides.iocdi.dependson"/>
</beans>

测试

package com.luo.spring.guides.iocdi.dependson.annotation;import com.luo.spring.guides.iocdi.dependson.domain.Singer;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 19:29* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/dependson/app-context-annotation.xml");ctx.refresh();Singer johnMayer = ctx.getBean("johnMayer", Singer.class);johnMayer.sing();ctx.close();}}

输出

Cm Eb Fm Ab Bb

四、继承关系

package com.luo.spring.guides.iocdi.inheritance;/*** Created by iuliana.cosmina on 2/25/17.*/
public class Singer {private String name;private int age;public void setName(String name) {this.name = name;}public void setAge(int age) {this.age = age;}public String toString() {return "\tName: " + name + "\n\t" + "Age: " + age;}
}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="parent" class="com.luo.spring.guides.iocdi.inheritance.Singer"p:name="John Mayer" p:age="39" /><bean id="child" class="com.luo.spring.guides.iocdi.inheritance.Singer"parent="parent" p:age="0"/>
</beans>

测试

package com.luo.spring.guides.iocdi.inheritance;import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 20:13* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/inheritance/app-context-xml.xml");ctx.refresh();Singer parent = (Singer) ctx.getBean("parent");Singer child = (Singer) ctx.getBean("child");System.out.println("Parent:\n" + parent);System.out.println("Child:\n" + child);System.out.println(parent == child);}}

输出

Parent:
Name: John Mayer
Age: 39
Child:
Name: John Mayer
Age: 0

false

五、scope

package com.luo.spring.guides.iocdi.scope;import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;@Component("nonSingleton")
@Scope("prototype")
public class Singer {private String name = "unknown";public Singer(@Value("John Mayer") String name) {this.name = name;}@Override public String toString() {return  name;}
}

1、xml 形式

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:c="http://www.springframework.org/schema/c"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="nonSingleton" class="com.luo.spring.guides.iocdi.scope.Singer"scope="prototype" c:_0="John Mayer"/>
</beans>

测试

package com.luo.spring.guides.iocdi.scope.xml;import com.luo.spring.guides.iocdi.scope.Singer;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 20:36* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/scope/app-context-xml.xml");ctx.refresh();Singer singer1 = ctx.getBean("nonSingleton", Singer.class);Singer singer2 = ctx.getBean("nonSingleton", Singer.class);System.out.println("Identity Equal?: " + (singer1 == singer2));System.out.println("Value Equal:? " + singer1.equals(singer2));System.out.println(singer1);System.out.println(singer2);ctx.close();}
}

输出

Identity Equal?: false
Value Equal:? false
John Mayer
John Mayer

2、注解形式

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd"><context:component-scanbase-package="com.luo.spring.guides.iocdi.scope"/>
</beans>

测试

package com.luo.spring.guides.iocdi.scope.annotation;import com.luo.spring.guides.iocdi.scope.Singer;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/11/30 20:36* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/scope/app-context-annotation.xml");ctx.refresh();Singer singer1 = ctx.getBean("nonSingleton", Singer.class);Singer singer2 = ctx.getBean("nonSingleton", Singer.class);System.out.println("Identity Equal?: " + (singer1 == singer2));System.out.println("Value Equal:? " + singer1.equals(singer2));System.out.println(singer1);System.out.println(singer2);ctx.close();}
}

输出

Identity Equal?: false
Value Equal:? false
John Mayer
John Mayer

六、replaced-method

• 性能较差

package com.luo.spring.guides.iocdi.replace;public class ReplacementTarget {public String formatMessage(String msg) {return "<h1>" + msg + "</h1>"; }public String formatMessage(Object msg) {return "<h1>" + msg + "</h1>"; }
}

package com.luo.spring.guides.iocdi.replace;import org.springframework.beans.factory.support.MethodReplacer;import java.lang.reflect.Method;public class FormatMessageReplacer implements MethodReplacer {@Overridepublic Object reimplement(Object arg0, Method method, Object[] args)throws Throwable {if (isFormatMessageMethod(method)) {String msg = (String) args[0];return "<h2>" + msg + "</h2>";} else {throw new IllegalArgumentException("Unable to reimplement method "+ method.getName());}}private boolean isFormatMessageMethod(Method method) {if (method.getParameterTypes().length != 1) {return false;}if (!("formatMessage".equals(method.getName()))) {return false;}if (method.getReturnType() != String.class) {return false;}if (method.getParameterTypes()[0] != String.class) {return false;}return true;}
}

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="methodReplacer" class="com.luo.spring.guides.iocdi.replace.FormatMessageReplacer"/><bean id="replacementTarget" class="com.luo.spring.guides.iocdi.replace.ReplacementTarget"><replaced-method name="formatMessage" replacer="methodReplacer"><arg-type>String</arg-type></replaced-method></bean><bean id="standardTarget" class="com.luo.spring.guides.iocdi.replace.ReplacementTarget"/>
</beans>

测试

package com.luo.spring.guides.iocdi.replace;import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.util.StopWatch;public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("iocdi/injection/replace/app-context-xml.xml");ctx.refresh();ReplacementTarget replacementTarget = (ReplacementTarget) ctx.getBean("replacementTarget");ReplacementTarget standardTarget = (ReplacementTarget) ctx.getBean("standardTarget");displayInfo("replacementTarget", replacementTarget);displayInfo("standardTarget", standardTarget);ctx.close();}private static void displayInfo(String name, ReplacementTarget target) {System.out.println(target.formatMessage(name + ":Thanks for playing, try again!"));StopWatch stopWatch = new StopWatch();stopWatch.start("perfTest");for (int x = 0; x < 1000000; x++) {String out = target.formatMessage("No filter in my head");//commented to not pollute the console//System.out.println(out);}stopWatch.stop();System.out.println("1000000 invocations took: "+ stopWatch.getTotalTimeMillis() + " ms");}
}

输出

<h2>replacementTarget:Thanks for playing, try again!</h2>
1000000 invocations took: 285 ms
<h1>standardTarget:Thanks for playing, try again!</h1>
1000000 invocations took: 43 ms

七、配置文件嵌套

package com.luo.spring.guides.iocdi.nesting;public class Song {private String title;public void setTitle(String title) {this.title = title;}public String getTitle() {return title;}
}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:c="http://www.springframework.org/schema/c"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="childTitle" class="java.lang.String" c:_0="Daughters"/><bean id="parentTitle" class="java.lang.String" c:_0="Gravity"/>
</beans>

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:c="http://www.springframework.org/schema/c"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="song1" class="com.apress.prospring5.ch3.Song"p:title-ref="parentTitle"/><bean id="song2" class="com.apress.prospring5.ch3.Song"p:title-ref="childTitle"/><bean id="song3" class="com.apress.prospring5.ch3.Song"><property name="title"><ref parent="childTitle"/></property> </bean><bean id="childTitle" class="java.lang.String" c:_0="No Such Thing"/>
</beans>

测试

package com.luo.spring.guides.iocdi.nesting;import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/12/1 13:26* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext parent = new GenericXmlApplicationContext();parent.load("classpath:iocdi/injection/nesting/parent-context.xml");parent.refresh();GenericXmlApplicationContext child = new GenericXmlApplicationContext();child.load("classpath:iocdi/injection/nesting/child-context.xml");child.setParent(parent);child.refresh();Song song1 = (Song) child.getBean("song1");Song song2 = (Song) child.getBean("song2");Song song3 = (Song) child.getBean("song3");System.out.println("from parent ctx: " + song1.getTitle());System.out.println("from child ctx: " + song2.getTitle());System.out.println("from parent ctx: " + song3.getTitle());child.close();parent.close();}
}

输出

from parent ctx: Gravity
from child ctx: No Such Thing
from parent ctx: Daughters

八、懒加载 lazy-init

• 懒加载：指 Spring 延迟加载 bean 的属性。
• lazy-init 的属性值为 true，这样就不会在 Spring 启动时进行实例化，而是在第一次通过 getbean 获取 bean 时实例化。
• lazy-init=“false” 只对 scope 属性为 singleton 才有效，如果 scope 属性为 pototype，无论 lazy-init 的属性值是什么，都只在通过 getbean 时进行实例化。

1、xml 形式

package com.luo.spring.guides.iocdi.domain;import org.springframework.stereotype.Component;/*** Created by iuliana.cosmina on 2/22/17.*/
public class Guitar {public void sing(){System.out.println("Cm Eb Fm Ab Bb");}
}

package com.luo.spring.guides.iocdi.domain;/*** @author : archer* @date : Created in 2022/11/30 14:37* @description :*/
public class Singer {private String message = "Default message";private Guitar guitar;public void setMessage(String message) {this.message = message;}public String getMessage() {return message;}public void setGuitar(Guitar guitar) {this.guitar = guitar;}public void sing() {guitar.sing();}
}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="singer"class="com.luo.spring.guides.iocdi.domain.Singer"p:guitar-ref="guitar" lazy-init="true"/><bean id="guitar"class="com.luo.spring.guides.iocdi.domain.Guitar" lazy-init="true"/>
</beans>

测试

package com.luo.spring.guides.iocdi.lazyinit;import com.luo.spring.guides.iocdi.domain.Singer;
import org.springframework.context.support.GenericXmlApplicationContext;/*** @author : archer* @date : Created in 2022/12/1 13:32* @description :*/
public class Main {public static void main(String... args) {GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();ctx.load("classpath:iocdi/injection/lazyinit/app-context-lazy-xml.xml");ctx.refresh();Singer singer = ctx.getBean("singer",Singer.class);singer.sing();ctx.close();}
}

输出

Cm Eb Fm Ab Bb

2、注解形式

package com.luo.spring.guides.iocdi.lazyinit.annotation;import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;/*** Created by iuliana.cosmina on 2/22/17.*/
@Component
@Lazy
public class Guitar {public void sing(){System.out.println("Cm Eb Fm Ab Bb");}
}

package com.luo.spring.guides.iocdi.lazyinit.annotation;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;/*** @author : archer* @date : Created in 2022/11/30 14:37* @description :*/
@Component
@Lazy
public class Singer {private String message = "Default message";private Guitar guitar;public void setMessage(String message) {this.message = message;}public String getMessage() {return message;}@Autowiredpublic void setGuitar(Guitar guitar) {this.guitar = guitar;}public void sing() {guitar.sing();}
}

测试

package com.luo.spring.guides.iocdi.lazyinit.annotation;import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.GenericApplicationContext;/*** @author : archer* @date : Created in 2022/12/1 13:47* @description :*/
public class Main {@Configuration@ComponentScan(basePackages = {"com.luo.spring.guides.iocdi.lazyinit.annotation"})public static class LazyConfig {}public static void main(String... args) {GenericApplicationContext ctx = new AnnotationConfigApplicationContext(LazyConfig.class);Singer singer = ctx.getBean("singer",Singer.class);singer.sing();}
}

输出

Cm Eb Fm Ab Bb

九、其他

package com.luo.spring.guides.common;import lombok.Data;
import lombok.ToString;import java.util.List;/*** @author : archer* @date : Created in 2022/9/28 17:21* @description :*/
@Data
@ToString
public class TestBean {private String testStr;private List<String> list;public TestBean() {this.testStr = "helloworld";}
}

1、使用 DefaultListableBeanFactory

<?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="testBean" name="testBeanName" class="com.luo.spring.guides.common.TestBean"/>
</beans>

测试

package com.luo.spring.guides.iocdi.other;import com.luo.spring.guides.common.TestBean;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.core.io.ClassPathResource;public class DefaultListableBeanFactoryMain {public static void main(String... args) {DefaultListableBeanFactory factory = new DefaultListableBeanFactory();XmlBeanDefinitionReader rdr = new XmlBeanDefinitionReader(factory);rdr.loadBeanDefinitions(new ClassPathResource("iocdi/injection/other/xml-bean-factory-config.xml"));TestBean testBean = (TestBean) factory.getBean("testBeanName");System.out.println(testBean.getTestStr());}
}

输出

helloworld

2、混合使用

package com.luo.spring.guides.iocdi.mixed;import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;/*** @author : archer* @date : Created in 2022/12/1 13:53* @description :*/
@ImportResource(locations = {"classpath:iocdi/injection/mixed/app-context-xml.xml"})
@Configuration
public class MixedConfiguration {
}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="testBean"class="com.luo.spring.guides.common.TestBean"/>
</beans>

测试

package com.luo.spring.guides.iocdi.mixed;import com.luo.spring.guides.common.TestBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;/*** @author : archer* @date : Created in 2022/12/1 13:53* @description :*/
public class Main {public static void main(String... args) {ApplicationContext ctx = new AnnotationConfigApplicationContext(MixedConfiguration.class);TestBean mr = ctx.getBean("testBean", TestBean.class);System.out.println(mr);}
}

输出

TestBean(testStr=helloworld, list=null)