入门注解@Required

siye@r480:~/svlution/workspace/springcore4322$ tree src/
src/
├── main
│   ├── java
│   │   ├── log4j.properties
│   │   └── ocn
│   │       └── site
│   │           └── springioc
│   │               ├── domain
│   │               │   ├── Person.java
│   │               │   └── User.java
│   │               └── setup
│   │                   └── Appconfig.java
│   └── resources
└── test
    ├── java
    │   └── ocn
    │       └── site
    │           └── springioc
    │               └── domain
    │                   └── Runtest.java
    └── resources

15 directories, 5 files

<dependency>
    <groupId>org.springframeworkgroupId>
    <artifactId>spring-contextartifactId>
    <version>4.3.22.RELEASEversion>
dependency>

<dependency>
    <groupId>log4jgroupId>
    <artifactId>log4jartifactId>
    <version>1.2.17version>
dependency>

<dependency>
    <groupId>junitgroupId>
    <artifactId>junitartifactId>
    <version>4.12version>
    <scope>testscope>
dependency>

<dependency>
    <groupId>org.springframeworkgroupId>
    <artifactId>spring-testartifactId>
    <version>4.3.22.RELEASEversion>
    <scope>testscope>
dependency>

package ocn.site.springioc.domain;

import org.springframework.stereotype.Component;

@Component
public class Person {

}

package ocn.site.springioc.domain;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Required;
import org.springframework.stereotype.Component;

@Component
public class User {

	private Person person;

	public Person getPerson() {
		return person;
	}

//	此注解标记无实际意义
//	注解 Autowired 的默认值完全可以取代
//	表示,此依赖项是必须被注入的.
//	注意 : 必须和 Autowired 同处使用.
// 该注解属性中的默认具有同等的效果。
	@Autowired
	@Required
	public void setPerson(Person person) {
		this.person = person;
	}

}

package ocn.site.springioc.setup;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan({ "ocn.site.springioc.domain" })
public class Appconfig {

}

package ocn.site.springioc.domain;

import org.apache.log4j.Logger;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;

import ocn.site.springioc.setup.Appconfig;

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = Appconfig.class)
public class Runtest {

	private final Logger logger = Logger.getLogger(this.getClass());
	private @Autowired ApplicationContext context;

	@Test
	public void run() throws Exception {
		logger.info(context.getBean(User.class));
	}

}

19-09-09 10:44:47 org.springframework.test.context.support.DefaultTestContextBootstrapper  =====>>> Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener]
19-09-09 10:44:47 org.springframework.test.context.support.DefaultTestContextBootstrapper  =====>>> Using TestExecutionListeners: [org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@3b81a1bc, org.springframework.test.context.support.DependencyInjectionTestExecutionListener@64616ca2, org.springframework.test.context.support.DirtiesContextTestExecutionListener@13fee20c]
19-09-09 10:44:47 org.springframework.context.support.GenericApplicationContext  =====>>> Refreshing org.springframework.context.support.GenericApplicationContext@3a82f6ef: startup date [Mon Sep 09 10:44:47 CST 2019]; root of context hierarchy
19-09-09 10:44:47 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor  =====>>> JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
19-09-09 10:44:48 ocn.site.springioc.domain.Runtest  =====>>> ocn.site.springioc.domain.User@703580bf
19-09-09 10:44:48 org.springframework.context.support.GenericApplicationContext  =====>>> Closing org.springframework.context.support.GenericApplicationContext@3a82f6ef: startup date [Mon Sep 09 10:44:47 CST 2019]; root of context hierarchy