一、Spring註解版之組件註冊-@Configuration&@Bean給容器中註冊組件

創建 Maven 工程；

加入 Spring所需 pom.xml 依賴:

<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context</artifactId>
   <version>4.3.12.RELEASE</version>
</dependency>

1. 傳統 Spring 配置文件 的 HelloWorld

   Person 類:

   package com.kino.bean;
   
   /**
    * Created by RM on 2019/2/18.
    */
   public class Person {
   
       private String name;
       private Integer age;
   
       public String getName() {
           return name;
       }
   
       public void setName(String name) {
           this.name = name;
       }
   
       public Integer getAge() {
           return age;
       }
   
       public void setAge(Integer age) {
           this.age = age;
       }
   
       public Person(String name, Integer age) {
           this.name = name;
           this.age = age;
       }
   
       public Person() {
   
       }
   
       @Override
       public String toString() {
           return "Person{" +
                   "name='" + name + '\'' +
                   ", age=" + age +
                   '}';
       }
   }
   

   Spring 配置文件:

   <?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="person" class="com.kino.bean.Person">
           <property name="age" value="18"/>
           <property name="name" value="張三"/>
       </bean>
   
   </beans>
   

   測試類:

   package com.kino.test;
   
   import com.kino.bean.Person;
   import org.springframework.context.ApplicationContext;
   import org.springframework.context.support.ClassPathXmlApplicationContext;
   
   /**
    * Created by RM on 2019/2/18.
    */
   public class MyTest {
   
       public static void main(String[] args) {
           ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
           Person person = (Person) context.getBean("person");
           System.out.println(person);
       }
   
   }
   

   測試結果:

   "D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\bin\java" "-javaagent:D:\SoftWare\IDEA\InstallationPath\IntelliJ IDEA 2017.2.2\lib\idea_rt.jar=55334:D:\SoftWare\IDEA\InstallationPath\IntelliJ IDEA 2017.2.2\bin" -Dfile.encoding=UTF-8 -classpath "D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\charsets.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\deploy.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\access-bridge.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\cldrdata.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\dnsns.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\jaccess.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\jfxrt.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\localedata.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\nashorn.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunec.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunjce_provider.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunmscapi.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunpkcs11.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\zipfs.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\javaws.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jce.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jfr.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jfxswt.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jsse.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\management-agent.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\plugin.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\resources.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\rt.jar;D:\Work\IDEA\springannotation\target\classes;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-context\4.3.12.RELEASE\spring-context-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-aop\4.3.12.RELEASE\spring-aop-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-beans\4.3.12.RELEASE\spring-beans-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-core\4.3.12.RELEASE\spring-core-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-expression\4.3.12.RELEASE\spring-expression-4.3.12.RELEASE.jar" com.kino.test.MyTest
   二月 18, 2019 10:20:38 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
   信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@156ce6a: startup date [Mon Feb 18 22:20:38 CST 2019]; root of context hierarchy
   二月 18, 2019 10:20:38 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
   信息: Loading XML bean definitions from class path resource [beans.xml]
   Person{name='張三', age=18}
   
   Process finished with exit code 0
   

2. spring 註解配置
   還是原來的 Person 類

   新增一個 配置類:

   package com.kino.config;
   
   import com.kino.bean.Person;
   import org.springframework.context.annotation.Bean;
   import org.springframework.context.annotation.Configuration;
   
   /**
    * Created by RM on 2019/2/18.
    */
   // 配置類 == Spring 的配置文件
   //@Configuration: 告訴 Spring, 這個類是一個配置類
   @Configuration
   public class MyConfig {
   
       //給容器中註冊一個Bean; 類型爲返回值的類型; id默認爲用方法名作爲id
       @Bean
       public Person getPerson(){
           return new Person("kino", 23);
       }
   
   }
   

   測試類:

   package com.kino.test;
   
   import com.kino.bean.Person;
   import com.kino.config.MyConfig;
   import org.springframework.context.ApplicationContext;
   import org.springframework.context.annotation.AnnotationConfigApplicationContext;
   
   /**
    * Created by RM on 2019/2/18.
    */
   public class MyTest {
   
       public static void main(String[] args) {
   //        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
   //        Person person = (Person) context.getBean("person");
   //        System.out.println(person);
   
           ApplicationContext context = new AnnotationConfigApplicationContext(MyConfig.class);
           Person person = (Person) context.getBean("getPerson");
           System.out.println(person);
   
   
       }
   
   }
   

   測試結果:

   "D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\bin\java" "-javaagent:D:\SoftWare\IDEA\InstallationPath\IntelliJ IDEA 2017.2.2\lib\idea_rt.jar=55635:D:\SoftWare\IDEA\InstallationPath\IntelliJ IDEA 2017.2.2\bin" -Dfile.encoding=UTF-8 -classpath "D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\charsets.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\deploy.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\access-bridge.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\cldrdata.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\dnsns.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\jaccess.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\jfxrt.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\localedata.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\nashorn.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunec.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunjce_provider.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunmscapi.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\sunpkcs11.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\ext\zipfs.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\javaws.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jce.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jfr.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jfxswt.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\jsse.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\management-agent.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\plugin.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\resources.jar;D:\SoftWare\jdk\InstallationPath\jdk 1.8 161M\jre\lib\rt.jar;D:\Work\IDEA\springannotation\target\classes;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-context\4.3.12.RELEASE\spring-context-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-aop\4.3.12.RELEASE\spring-aop-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-beans\4.3.12.RELEASE\spring-beans-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-core\4.3.12.RELEASE\spring-core-4.3.12.RELEASE.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;D:\SoftWare\maven\InstallationPath\apache-maven\lib\org\springframework\spring-expression\4.3.12.RELEASE\spring-expression-4.3.12.RELEASE.jar" com.kino.test.MyTest
   二月 18, 2019 10:33:58 下午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
   信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@13c675d: startup date [Mon Feb 18 22:33:58 CST 2019]; root of context hierarchy
   Person{name='kino', age=23}
   
   Process finished with exit code 0
   

@Bean 註解:

//給容器中註冊一個Bean; 類型爲返回值的類型; id默認爲用方法名作爲id
@Bean
public Person getPerson(){
    return new Person("kino", 23);
}

等同於配置文件的

<bean id="person" class="com.kino.bean.Person">
    <property name="age" value="18"/>
    <property name="name" value="張三"/>
</bean>

@Bean 註解源碼:

@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Bean {

	//定義Id
	/**
	*   @Bean(name="person1")
	*	public Person getPerson(){}
	*	
	*	Person person = (Person) context.getBean("person1");
	*/
    @AliasFor("name") 
    String[] value() default {};

    @AliasFor("value")
    String[] name() default {};

    Autowire autowire() default Autowire.NO;

    String initMethod() default "";

    String destroyMethod() default "(inferred)";
}