@Autowired注解

changelog.md

@@ -1075,11 +1075,52 @@ public class ValueAnnotationTest {
 
 ```
 
+## @Autowired注解
+> 分支：autowired-annotation
 
+@Autowired注解的处理见AutowiredAnnotationBeanPostProcessor#postProcessPropertyValues
 
+测试：
+```
+@Component
+public class Car {
 
+}
 
+@Component
+public class Person implements InitializingBean, DisposableBean {
 
+	@Autowired
+	private Car car;
+}
+```
+autowired-annotation.xml
+```
+<?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/beans
+	         http://www.springframework.org/schema/beans/spring-beans.xsd
+		 http://www.springframework.org/schema/context
+		 http://www.springframework.org/schema/context/spring-context-4.0.xsd">
+
+    <context:component-scan base-package="org.springframework.test.bean"/>
+
+</beans>
+```
+```
+public class AutowiredAnnotationTest {
+
+	@Test
+	public void testAutowiredAnnotation() throws Exception {
+		ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:autowired-annotation.xml");
+
+		Person person = applicationContext.getBean(Person.class);
+		assertThat(person.getCar()).isNotNull();
+	}
+}
+```
 
 
 

src/main/java/org/springframework/beans/factory/BeanFactory.java

@@ -29,4 +29,6 @@ public interface BeanFactory {
 	 * @throws BeansException
 	 */
 	<T> T getBean(String name, Class<T> requiredType) throws BeansException;
+
+	<T> T getBean(Class<T> requiredType) throws BeansException;
 }

src/main/java/org/springframework/beans/factory/annotation/Autowired.java

@@ -0,0 +1,16 @@
+package org.springframework.beans.factory.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * @author derekyi
+ * @date 2020/12/27
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.CONSTRUCTOR, ElementType.FIELD, ElementType.METHOD})
+public @interface Autowired {
+
+}

src/main/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessor.java

@@ -39,7 +39,23 @@ public PropertyValues postProcessPropertyValues(PropertyValues pvs, Object bean,
 			}
 		}
 
-		//处理@Autowired注解（下一节实现）
+		//处理@Autowired注解
+		for (Field field : fields) {
+			Autowired autowiredAnnotation = field.getAnnotation(Autowired.class);
+			if (autowiredAnnotation != null) {
+				Class<?> fieldType = field.getType();
+				String dependentBeanName = null;
+				Qualifier qualifierAnnotation = field.getAnnotation(Qualifier.class);
+				Object dependentBean = null;
+				if (qualifierAnnotation != null) {
+					dependentBeanName = qualifierAnnotation.value();
+					dependentBean = beanFactory.getBean(dependentBeanName, fieldType);
+				} else {
+					dependentBean = beanFactory.getBean(fieldType);
+				}
+				BeanUtil.setFieldValue(bean, field.getName(), dependentBean);
+			}
+		}
 
 		return pvs;
 	}

src/main/java/org/springframework/beans/factory/annotation/Qualifier.java

@@ -0,0 +1,17 @@
+package org.springframework.beans.factory.annotation;
+
+import java.lang.annotation.*;
+
+/**
+ * @author derekyi
+ * @date 2020/12/27
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE, ElementType.ANNOTATION_TYPE})
+@Inherited
+@Documented
+public @interface Qualifier {
+
+	String value() default "";
+
+}

src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -4,9 +4,7 @@
 import org.springframework.beans.factory.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.config.BeanDefinition;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
 
 /**
  * @author derekyi
@@ -50,6 +48,22 @@ public <T> Map<String, T> getBeansOfType(Class<T> type) throws BeansException {
 		return result;
 	}
 
+	public <T> T getBean(Class<T> requiredType) throws BeansException {
+		List<String> beanNames = new ArrayList<>();
+		for (Map.Entry<String, BeanDefinition> entry : beanDefinitionMap.entrySet()) {
+			Class beanClass = entry.getValue().getBeanClass();
+			if (requiredType.isAssignableFrom(beanClass)) {
+				beanNames.add(entry.getKey());
+			}
+		}
+		if (beanNames.size() == 1) {
+			return getBean(beanNames.get(0), requiredType);
+		}
+
+		throw new BeansException(requiredType + "expected single bean but found " +
+				beanNames.size() + ": " + beanNames);
+	}
+
 	@Override
 	public String[] getBeanDefinitionNames() {
 		Set<String> beanNames = beanDefinitionMap.keySet();

src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -128,6 +128,10 @@ public <T> Map<String, T> getBeansOfType(Class<T> type) throws BeansException {
 		return getBeanFactory().getBeansOfType(type);
 	}
 
+	public <T> T getBean(Class<T> requiredType) throws BeansException {
+		return getBeanFactory().getBean(requiredType);
+	}
+
 	public Object getBean(String name) throws BeansException {
 		return getBeanFactory().getBean(name);
 	}

src/test/java/org/springframework/test/bean/Person.java

@@ -2,17 +2,21 @@
 
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
 
 /**
  * @author derekyi
  * @date 2020/11/24
  */
+@Component
 public class Person implements InitializingBean, DisposableBean {
 
 	private String name;
 
 	private int age;
 
+	@Autowired
 	private Car car;
 
 	public void customInitMethod() {

src/test/java/org/springframework/test/ioc/AutowiredAnnotationTest.java

@@ -0,0 +1,22 @@
+package org.springframework.test.ioc;
+
+import org.junit.Test;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+import org.springframework.test.bean.Person;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author derekyi
+ * @date 2020/12/27
+ */
+public class AutowiredAnnotationTest {
+
+	@Test
+	public void testAutowiredAnnotation() throws Exception {
+		ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:autowired-annotation.xml");
+
+		Person person = applicationContext.getBean(Person.class);
+		assertThat(person.getCar()).isNotNull();
+	}
+}

src/test/resources/autowired-annotation.xml

@@ -0,0 +1,16 @@
+<?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/beans
+	         http://www.springframework.org/schema/beans/spring-beans.xsd
+		 http://www.springframework.org/schema/context
+		 http://www.springframework.org/schema/context/spring-context-4.0.xsd">
+
+    <bean class="org.springframework.beans.factory.PropertyPlaceholderConfigurer">
+        <property name="location" value="classpath:car.properties" />
+    </bean>
+
+    <context:component-scan base-package="org.springframework.test.bean"/>
+
+</beans>