类的设计
继承和实现了一系列接口
比如描述生命周期的
public interface Lifecycle {
void start();
void stop();
boolean isRunning();
}
在AbstractApplicationContext中，写了核心的refresh的设计如下
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
initMessageSource();
// Initialize event multicaster for this context.
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// Check for listener beans and register them.
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// Destroy already created singletons to avoid dangling resources.
destroyBeans();
// Reset 'active' flag.
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}
postProcessBeanFactory
finishBeanFactoryInitialization
其中，在finishBeanFactoryInitialization完成用户定义的非懒加载的类的初始化
//org.springframework.beans.BeanUtils
ReflectionUtils.makeAccessible(ctor);
return ctor.newInstance(args);
然后调用
try {
populateBean(beanName, mbd, instanceWrapper);
if (exposedObject != null) {
exposedObject = initializeBean(beanName, exposedObject, mbd);
}
}
populateBean完成依赖注入。
initializeBean进行初始化。
initializeBean代码如下
//org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java:436
protected Object createProxy(
Class<?> beanClass, String beanName, Object[] specificInterceptors, TargetSource targetSource) {
if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
AutoProxyUtils.exposeTargetClass((ConfigurableListableBeanFactory) this.beanFactory, beanName, beanClass);
}
ProxyFactory proxyFactory = new ProxyFactory();
proxyFactory.copyFrom(this);
if (!proxyFactory.isProxyTargetClass()) {
if (shouldProxyTargetClass(beanClass, beanName)) {
proxyFactory.setProxyTargetClass(true);
}
else {
evaluateProxyInterfaces(beanClass, proxyFactory);
}
}
Advisor[] advisors = buildAdvisors(beanName, specificInterceptors);
proxyFactory.addAdvisors(advisors);
proxyFactory.setTargetSource(targetSource);
customizeProxyFactory(proxyFactory);
proxyFactory.setFrozen(this.freezeProxy);
if (advisorsPreFiltered()) {
proxyFactory.setPreFiltered(true);
}
return proxyFactory.getProxy(getProxyClassLoader());
}
JdkDynamicAopProxy底层使用了sun.misc.ProxyGenerator#generateClassFile来生成代码文件。然后使用classLoader进行加载。这就是标准的java动态代理机制。
注意，此时，生成的类知识传入了类名和其实现的接口，并不包含具体的实现。最后调用
private static native Object newInstance0(Constructor<?> var0, Object[] var1) throws InstantiationException, IllegalArgumentException, InvocationTargetException;
传入JdkDynamicAopProxy对象。
直接查看对象有点难,我们找一个网商已经搞好的。
/*
* Decompiled with CFR 0_110.
*
* Could not load the following classes:
* com.sun.proxy.$Proxy0
* ctgu.bytecode.proxy.service.HelloService
*/
package com.sun.proxy;
import ctgu.bytecode.proxy.service.HelloService;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.UndeclaredThrowableException;
public final class $Proxy0
extends Proxy
implements HelloService {
private static Method m1;
private static Method m3;
private static Method m2;
private static Method m0;
public $Proxy0(InvocationHandler invocationHandler) {
super(invocationHandler);
}
public final boolean equals(Object object) {
try {
return (Boolean)this.h.invoke((Object)this, m1, new Object[]{
object});
}
catch (Error | RuntimeException v0) {
throw v0;
}
catch (Throwable var2_2) {
throw new UndeclaredThrowableException(var2_2);
}
}
public final String sayHello(String string) {
try {
return (String)this.h.invoke((Object)this, m3, new Object[]{
string});
}
catch (Error | RuntimeException v0) {
throw v0;
}
catch (Throwable var2_2) {
throw new UndeclaredThrowableException(var2_2);
}
}
public final String toString() {
try {
return (String)this.h.invoke((Object)this, m2, null);
}
catch (Error | RuntimeException v0) {
throw v0;
}
catch (Throwable var1_1) {
throw new UndeclaredThrowableException(var1_1);
}
}
public final int hashCode() {
try {
return (Integer)this.h.invoke((Object)this, m0, null);
}
catch (Error | RuntimeException v0) {
throw v0;
}
catch (Throwable var1_1) {
throw new UndeclaredThrowableException(var1_1);
}
}
static {
try {
m1 = Class.forName("java.lang.Object").getMethod("equals", Class.forName("java.lang.Object"));
m3 = Class.forName("ctgu.bytecode.proxy.service.HelloService").getMethod("sayHello", Class.forName("java.lang.String"));
m2 = Class.forName("java.lang.Object").getMethod("toString", new Class[0]);
m0 = Class.forName("java.lang.Object").getMethod("hashCode", new Class[0]);
return;
}
catch (NoSuchMethodException var1) {
throw new NoSuchMethodError(var1.getMessage());
}
catch (ClassNotFoundException var1_1) {
throw new NoClassDefFoundError(var1_1.getMessage());
}
}
}
AbstractRefreshableApplicationContext持有一个DefaultListableBeanFactory对象。这个对象就是用于生成对象的。
DefaultListableBeanFactory同时维护所有bean的定义。
/** Map of bean definition objects, keyed by bean name */
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(256);
BeanDefinition就是在xml中我们配置的内容。