入门注解@DependsOn

siye@r480:~/svlution/workspace/springcore4322$ tree src/
src/
├── main
│   ├── java
│   │   ├── log4j.properties
│   │   └── ocn
│   │       └── site
│   │           └── springioc
│   │               ├── domain
│   │               │   ├── PersonInit.java
│   │               │   ├── Person.java
│   │               │   └── User.java
│   │               └── setup
│   │                   └── Appconfig.java
│   └── resources
└── test├── java│   └── ocn│       └── site│           └── springioc│               └── domain│                   └── Runtest.java└── resources15 directories, 6 files

<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>4.3.22.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
<dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>4.3.22.RELEASE</version><scope>test</scope>
</dependency>

package ocn.site.springioc.domain;import org.springframework.stereotype.Component;@Component
public class Person {private int id;public int getId() {return id;}public void setId(int id) {this.id = id;}}

package ocn.site.springioc.domain;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;@Component("personInit")
@Lazy
public class PersonInit {private Person person;public Person getPerson() {return person;}// 该注解必须标注在setter方法上，否则不会生效配置。@Autowiredpublic void setPerson(Person person) {person.setId(34);this.person = person;}}

package ocn.site.springioc.domain;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.DependsOn;
import org.springframework.stereotype.Component;//等价于 bean元素的 depend-on属性
//
//对于 A依赖于B,C依赖于B,但是A与C之间的依赖关系不是很明显.
//可是A的实例化,需要C的实例化.
//此时可使用强制依赖的注解标记.
//在实例化A的时候,强制实例化C
@Component
@DependsOn("personInit") // 不使用该注解的话，person的初始化配置不会被注入
public class User {private @Autowired Person person;public Person getPerson() {return person;}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.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 User user;@Testpublic void run() throws Exception {logger.info(user.getPerson().getId());}}

19-09-09 09:20:24 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 09:20:24 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 09:20:24 org.springframework.context.support.GenericApplicationContext  =====>>> Refreshing org.springframework.context.support.GenericApplicationContext@3a82f6ef: startup date [Mon Sep 09 09:20:24 CST 2019]; root of context hierarchy
19-09-09 09:20:24 ocn.site.springioc.domain.Runtest  =====>>> 34
19-09-09 09:20:24 org.springframework.context.support.GenericApplicationContext  =====>>> Closing org.springframework.context.support.GenericApplicationContext@3a82f6ef: startup date [Mon Sep 09 09:20:24 CST 2019]; root of context hierarchy

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