package com.lcs.spring.service;
import com.lcs.spring.annotation.Autowired;
import com.lcs.spring.annotation.Component;
import com.lcs.spring.annotation.ComponentScan;
import com.lcs.spring.annotation.Scope;
import java.beans.Introspector;
import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* @author zhongliudizhu
*/
public class LcsApplicationContext {
private Class configClass;
private final Map<String, BeanDefination> beanDelineationMap = new ConcurrentHashMap<>();
private final Map<String, Object> singletonsObjects = new ConcurrentHashMap<>();
private final List<BeanPostProcessor> beanDefinitionProcessor = new LinkedList<>();
public LcsApplicationContext(Class configClass) {
this.configClass = configClass;
scan(configClass);
for (Map.Entry<String, BeanDefination> entity : beanDelineationMap.entrySet()) {
String beanName = entity.getKey();
BeanDefination beanDefination = entity.getValue();
// 实例化普通bean
Object object = createBean(beanName, beanDefination);
singletonsObjects.put(beanName, object);
}
}
private Object createBean(String beanName, BeanDefination beanDefination) {
Class clazz = beanDefination.getType();
Object instance = null;
try {
instance = clazz.getConstructor().newInstance();
for (Field field : clazz.getDeclaredFields()) {
if (field.isAnnotationPresent(Autowired.class)) {
field.setAccessible(true);
field.set(instance, getBean(field.getName()));
}
}
// 初始化
if (instance instanceof InitializingBean) {
((InitializingBean) instance).afterPropertiesSet();
}
for (BeanPostProcessor beanPostProcessor : beanDefinitionProcessor) {
instance = beanPostProcessor.postProcessAfterInitialization(instance, beanName);
}
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
return instance;
}
public Object getBean(String beanName) {
if (!beanDelineationMap.containsKey(beanName)) {
throw new NullPointerException();
}
BeanDefination beanDefination = beanDelineationMap.get(beanName);
if (!"singleton".equals(beanDefination.getScope())) {
return createBean(beanName, beanDefination);
} else {
return singletonsObjects.get(beanName);
}
}
private void scan(Class configClass) {
if (configClass.isAnnotationPresent(ComponentScan.class)) {
ComponentScan componentScan = (ComponentScan) configClass.getAnnotation(ComponentScan.class);
String path = componentScan.value().replace(".", "/");
ClassLoader classLoader = LcsApplicationContext.class.getClassLoader();
URL path1 = classLoader.getResource(path);
File classPath = null;
try {
classPath = new File(path1.toURI());
if (classPath.isDirectory()) {
for (File file1 : classPath.listFiles()) {
String absolutePath = file1.getAbsoluteFile().getPath();
String classInfo = absolutePath.substring(absolutePath.lastIndexOf("com"), absolutePath.lastIndexOf(".class"));
classInfo = classInfo.replace(File.separatorChar, '.');
Class clazz = classLoader.loadClass(classInfo);
BeanDefination beanDefination = new BeanDefination();
beanDefination.setType(clazz);
if (clazz.isAnnotationPresent(Component.class)) {
if (BeanPostProcessor.class.isAssignableFrom(clazz)) {
BeanPostProcessor instance = (BeanPostProcessor) clazz.getConstructor().newInstance();
beanDefinitionProcessor.add(instance);
}
Component componentAnnotaion = (Component) clazz.getAnnotation(Component.class);
String beanName = componentAnnotaion.value();
if ("".equals(beanName)) {
// 起到的是转换作用
beanName = Introspector.decapitalize(clazz.getSimpleName());
}
if (clazz.isAnnotationPresent(Scope.class)) {
Scope scope = (Scope) clazz.getAnnotation(Scope.class);
String value = scope.value();
beanDefination.setScope(value);
} else {
beanDefination.setScope("singleton");
}
beanDelineationMap.put(beanName, beanDefination);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
lcs_create_spring.zip （30个子文件） 
lcs_create_spring src test java main resources java com lcs spring service 
OrderService.java 195B InitializingBean.java 226B BeanDefination.java 565B LcsApplicationContext.java 6KB UserInterface.java 127B UserService.java 611B BeanPostProcessor.java 615B LcsBeanPostPocessor.java 1KB annotation Scope.java 367B ComponentScan.java 375B Component.java 371B Autowired.java 372B AppConfig.java 185B Test.java 509B target generated-sources annotations classes com lcs spring service UserInterface.class 151B UserService.class 1KB InitializingBean.class 171B BeanDefination.class 995B LcsBeanPostPocessor.class 2KB LcsBeanPostPocessor$1.class 1KB OrderService.class 451B LcsApplicationContext.class 7KB BeanPostProcessor.class 371B annotation Autowired.class 459B ComponentScan.class 466B Component.class 458B Scope.class 450B AppConfig.class 404B Test.class 847B pom.xml 837B
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