对普通bean进行Autowired字段注入
工具类
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.SmartInitializingSingleton;
import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.lang.NonNull;
import org.springframework.stereotype.Component;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
/**
* 对普通bean(即:非spring-bean)的autowired注入支持
*
* @author JustryDeng
* @since 2020/7/5 13:20:19
*/
@Slf4j
public abstract class ExtAutowiredInjector {
public ExtAutowiredInjector() {
Object obj = applyAutowired();
ExtAutowiredInjector.inject(obj);
}
/**
* 对返回的object进行autowired注入处理
*
* @return 要进行注入处理的Object
*/
protected Object applyAutowired() {
return this;
}
/**
* 对目标对象中的被@Auwired标注了的字段进行注入
*
* @param obj
* 目标obj
*/
public static void inject(Object obj) {
if (obj == null) {
log.warn("obj is null, skip inject.");
return;
}
if (ExtAutowiredInjectorProcessor.applicationContext != null) {
ExtAutowiredInjectorProcessor.applicationContext.publishEvent(new AutowiredInjectEvent(obj));
} else {
ExtAutowiredInjectorProcessor.queue.add(obj);
}
}
/**
* Autowired注入支持事件
*
* @author JustryDeng
* @since 2020/7/5 15:02:19
*/
public static class AutowiredInjectEvent extends ApplicationEvent {
@Getter
private final Object bean;
/**
* Create a new ApplicationEvent.
*
* @param source
* the object on which the event initially occurred (never {@code null})
*/
public AutowiredInjectEvent(Object source) {
super(source);
Objects.requireNonNull(source, "source cannot be null.");
this.bean = source;
}
}
/**
* {@link ExtAutowiredInjector}处理器
*
* @author JustryDeng
* @since 2020/7/5 13:46:25
*/
@Slf4j
@Component
public static class ExtAutowiredInjectorProcessor implements SmartInitializingSingleton, ApplicationListener<AutowiredInjectEvent> {
static ApplicationContext applicationContext;
static Queue<Object> queue = new ConcurrentLinkedQueue<>();
private final AutowireCapableBeanFactory autowireCapableBeanFactory;
public ExtAutowiredInjectorProcessor(AutowireCapableBeanFactory autowireCapableBeanFactory,
ApplicationContext applicationContext) {
this.autowireCapableBeanFactory = autowireCapableBeanFactory;
ExtAutowiredInjectorProcessor.applicationContext = applicationContext;
}
@Override
public void onApplicationEvent(@NonNull AutowiredInjectEvent event) {
Object bean = event.getBean();
autowireCapableBeanFactory.autowireBean(bean);
afterSingletonsInstantiated();
}
@Override
public void afterSingletonsInstantiated() {
Object obj = queue.poll();
while (obj != null) {
autowireCapableBeanFactory.autowireBean(obj);
obj = queue.poll();
}
}
}
}
使用测试
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Component;
/**
* start class
*
* @author JustryDeng
* @since 2022/4/21 11:41
*/
@SpringBootApplication
public class DemoApplication implements ApplicationRunner {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@Override
public void run(ApplicationArguments args) throws Exception {
// 启动springboot项目， 观察输入
// 测试一，输出：hello 邓二洋~
new TestClassOne().who();
// 测试二，输出：hello 邓帅~
TestClassTwo testClassTwo = new TestClassTwo();
ExtAutowiredInjector.inject(testClassTwo);
testClassTwo.who();
// 重复注入也没关系
//ExtAutowiredInjector.inject(testClassTwo);
//ExtAutowiredInjector.inject(testClassTwo);
//ExtAutowiredInjector.inject(testClassTwo);
//testClassTwo.who();
}
/**
* 测试用法一：继承使用，自动完成注入
*/
public static class TestClassOne extends ExtAutowiredInjector {
@Autowired
@Qualifier("demoApplication.DengErYang")
private Mine mine;
public void who() {
System.err.println(mine.hello());
}
@Override
protected Object applyAutowired() {
return this;
}
}
/**
* 测试用法一：不继承， 直接用{@link ExtAutowiredInjector#inject(Object)}注入
*/
public static class TestClassTwo {
@Autowired
@Qualifier("demoApplication.DengShuai")
private Mine mine;
public void who() {
System.err.println(mine.hello());
}
}
public interface Mine {
String hello();
}
@Component(value = "demoApplication.DengErYang")
public static class DengErYang implements Mine {
@Override
public String hello() {
return "hello 邓二洋~";
}
}
@Component(value = "demoApplication.DengShuai")
public static class DengShuai implements Mine {
@Override
public String hello() {
return "hello 邓帅~";
}
}
}
启动程序，控制台输出：
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.6.6)
2022-04-21 13:47:39.176 INFO 15784 --- [ main] com.example.demo.DemoApplication : Starting DemoApplication using Java 1.8.0_291 on DESKTOP-K08MNSB with PID 15784 (E:\working\demo\demo\target\classes started by 邓沙利文 in E:\java\flex-server)
2022-04-21 13:47:39.179 INFO 15784 --- [ main] com.example.demo.DemoApplication : No active profile set, falling back to 1 default profile: "default"
2022-04-21 13:47:39.480 INFO 15784 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 0.509 seconds (JVM running for 0.9)
hello 邓二洋~
hello 邓帅~
Process finished with exit code 0
相关资料
- 本文已被收录进《程序员成长笔记》 ，笔者JustryDeng
