Spring AOP创建代理对象源码解析
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2021-04-03 21:26
1 工程简介
1.1 pom
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<spring.version>5.2.8.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.20</version>
</dependency>
<!-- 日志相关依赖 -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.10</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>${spring.version}</version>
</dependency>
</dependencies>1.2 AOP配置文件
@Configuration
@EnableAspectJAutoProxy
@Import({ServiceAopConfig.class, DaoAopConfig.class})
public class AopConfig {
}
@Configuration
@Aspect
public class DaoAopConfig {
/**
* 声明切点
*/
@Pointcut("execution(* com.rosh.dao.*.*(..))")
public void pointCut() {
}
@Around("pointCut()")
public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
System.out.println("DaoAopConfig invoke around start");
Object proceed = proceedingJoinPoint.proceed();
System.out.println("DaoAopConfig invoke around end");
return proceed;
}
}
@Configuration
@Aspect
public class ServiceAopConfig {
/**
* 声明切点
*/
@Pointcut("execution(* com.rosh.service.*.*(..))")
public void pointCut() {
}
@Around("pointCut()")
public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
System.out.println("ServiceAopConfig invoke around start");
Object proceed = proceedingJoinPoint.proceed();
System.out.println("ServiceAopConfig invoke around end");
return proceed;
}
@Before("pointCut()")
public void before(){
System.out.println("ServiceAopConfig invoke before");
}
@After("pointCut()")
public void after() {
System.out.println("ServiceAopConfig invoke after");
}
}1.3 StudentDao
@Repository
public class StudentDao {
public void addStudent() {
System.out.println("StudentDao invoke addStudent");
}
}1.4 Service
public interface StudentService {
void addStudent();
}
@Service
public class StudentServiceImpl implements StudentService {
@Override
public void addStudent() {
System.out.println("StudentServiceImpl invoke addStudent()");
}
}1.5 RoshTest
public class RoshTest {
@Test
public void mainTest(){
AnnotationConfigApplicationContext applicationContext=new AnnotationConfigApplicationContext("com.rosh");
StudentService studentService = (StudentService) applicationContext.getBean("studentServiceImpl");
studentService.addStudent();
System.out.println("===============分割线================");
StudentDao studentDao=(StudentDao) applicationContext.getBean("studentDao");
studentDao.addStudent();
}
}
2 AbstractAutoProxyCreator概述
描述：该类作用在，Spring Aop初始化源码分析中具体分析过，核心作用是，在bean初始化时，后置加强。
protected Object wrapIfNecessary(Object bean, String beanName, Object cacheKey) {
if (StringUtils.hasLength(beanName) && this.targetSourcedBeans.contains(beanName)) {
return bean;
}
if (Boolean.FALSE.equals(this.advisedBeans.get(cacheKey))) {
return bean;
}
if (isInfrastructureClass(bean.getClass()) || shouldSkip(bean.getClass(), beanName)) {
this.advisedBeans.put(cacheKey, Boolean.FALSE);
return bean;
}
// Create proxy if we have advice.
/**
* 【1】获取当前bean有效的Advisor，Advisor = advice + pointCut
*/
Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(bean.getClass(), beanName, null);
if (specificInterceptors != DO_NOT_PROXY) {
this.advisedBeans.put(cacheKey, Boolean.TRUE);
/**
* 【2】创建代理对象
*/
Object proxy = createProxy(
bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));
this.proxyTypes.put(cacheKey, proxy.getClass());
return proxy;
}
this.advisedBeans.put(cacheKey, Boolean.FALSE);
return bean;
}3 创建代理对象源码解析
3.1 createProxy
描述：主流程调用方法AbstractAutoProxyCreator类createProxy 方法。
protected Object createProxy(Class<?> beanClass, @Nullable String beanName,
@Nullable Object[] specificInterceptors, TargetSource targetSource) {
if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
AutoProxyUtils.exposeTargetClass((ConfigurableListableBeanFactory) this.beanFactory, beanName, beanClass);
}
/**
* 【1】创建代理工厂，赋值。
*/
ProxyFactory proxyFactory = new ProxyFactory();
proxyFactory.copyFrom(this);
/**
* 【2】 proxyTargetClass为true时代表使用cglib，为false使用jdk，默认值是false。
* 判断当前被代理对象是使用jdk增强还是使用cglib增强
*
*/
if (!proxyFactory.isProxyTargetClass()) {
//根据最开始@EnableAspectJAutoProxy注解中的proxyTargetClass参数判断是否应该使用cglib代理
if (shouldProxyTargetClass(beanClass, beanName)) {
proxyFactory.setProxyTargetClass(true);
}
else {
//如果是接口增强那么使用jdk，否则使用cglib
evaluateProxyInterfaces(beanClass, proxyFactory);
}
}
//构建advisor
Advisor[] advisors = buildAdvisors(beanName, specificInterceptors);
//把advisor加入到代理工厂中
proxyFactory.addAdvisors(advisors);
//把targetSource对象加入代理工厂(实际对象、被代理对象)
proxyFactory.setTargetSource(targetSource);
customizeProxyFactory(proxyFactory);
proxyFactory.setFrozen(this.freezeProxy);
if (advisorsPreFiltered()) {
proxyFactory.setPreFiltered(true);
}
/**
* 【3】 获取代理对象
*/
return proxyFactory.getProxy(getProxyClassLoader());
}3.2 ProxyFactory 获取代理对象
描述：先获取AOP代理
public Object getProxy(@Nullable ClassLoader classLoader) {
/**
* 创建AOP代理（JDK、CGLIB）并且获得代理对象
*/
return createAopProxy().getProxy(classLoader);
}protected final synchronized AopProxy createAopProxy() {
if (!this.active) {
activate();
}
return getAopProxyFactory().createAopProxy(this);
}@Override
public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException {
if (config.isOptimize() || config.isProxyTargetClass() || hasNoUserSuppliedProxyInterfaces(config)) {
// 如果targetClass是接口类，使用JDK来生成Proxy
Class<?> targetClass = config.getTargetClass();
if (targetClass == null) {
throw new AopConfigException("TargetSource cannot determine target class: " +
"Either an interface or a target is required for proxy creation.");
}
if (targetClass.isInterface() || Proxy.isProxyClass(targetClass)) {
return new JdkDynamicAopProxy(config);
}
// 如果不是接口类，使用CGLIB生成Proxy
return new ObjenesisCglibAopProxy(config);
}
else {
return new JdkDynamicAopProxy(config);
}
}3.3 根据AOP不同的代理获取代理对象
4 StudentDao 代理Debug
描述：每个代理对象都对应一个代理工厂，工厂是new 创建的。
描述：选择cglib、jdk代理生成代理对象。
描述：创建AOP代理。
描述：CglibAopProxy获取代理对象。
描述：获取到cglib增强代理对象。
5 StudentServiceImpl 代理Debug
描述：StudentServiceImpl 实现StudentService接口使用jdk代理。
描述：AOP获取JDK代理。
描述：获取代理对象。
出处：https://blog.csdn.net/qq_34125999/article/details/115107521
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