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SpringAOP那些无处不在的动态代理

环境配置

代码结构

pom.xml文件

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.gupaoedu</groupId> <artifactId>gupaoedu-springaop</artifactId> <version>0.0.1-SNAPSHOT</version> <name>gupaoedu-springaop</name> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.10</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.25</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> </dependency> </dependencies> </project>

application.properties文件

#多切面配置可以在key前面加前缀 #例如 aspect.logAspect. #切面表达式,expression# pointCut=public .* com.gupaoedu.springaop.demo.service..*Service..*(.*) #切面类# aspectClass=com.gupaoedu.springaop.demo.aspect.LogAspect #切面前置通知# aspectBefore=before #切面后置通知# aspectAfter=after #切面异常通知# aspectAfterThrow=afterThrowing #切面异常类型# aspectAfterThrowingName=java.lang.Exception

业务代码

Member实体类

package com.gupaoedu.springaop.demo.model; public class Member { }

IMermverServer接口

package com.gupaoedu.springaop.demo.service; import com.gupaoedu.springaop.demo.model.Member; /** * 注解版业务操作类 * @author Tom */ public interface IMemberService { public Member get(String id); public Member get(); public void save(Member member); public Boolean delete(String id) throws Exception; }

MemberService业务实现类

package com.gupaoedu.springaop.demo.service.impl; import com.gupaoedu.springaop.demo.model.Member; import com.gupaoedu.springaop.demo.service.IMemberService; import lombok.extern.slf4j.Slf4j; /** * 注解版业务操作类 * @author Tom */ @Slf4j public class MemberService implements IMemberService{ public Member get(String id){ log.info("getMemberById method . . ."); return new Member(); } public Member get(){ log.info("getMember method . . ."); return new Member(); } public void save(Member member){ log.info("save member method . . ."); } public Boolean delete(String id) throws Exception{ log.info("delete method . . ."); throw new Exception("spring aop ThrowAdvice演示"); } }

LogAspect切面增强类

package com.gupaoedu.springaop.demo.aspect; import lombok.extern.slf4j.Slf4j; /** * Created by Tom. */ @Slf4j public class LogAspect { //在调用一个方法之前，执行before方法 public void before(){ //这个方法中的逻辑，是由我们自己写的 log.info("Invoker Before Method!!!"); } //在调用一个方法之后，执行after方法 public void after(){ log.info("Invoker After Method!!!"); } public void afterThrowing(){ log.info("出现异常"); } }

仿写JDK动态代理

GPInvocationHandler JDK动态代理接口

package com.gupaoedu.springaop.framework.proxy; import java.lang.reflect.Method; /** * Created by Tom. */ public interface GPInvocationHandler { Object invoke(Object proxy, Method method, Object[] args) throws Throwable; }

GPClassLoader自定义类加载器

package com.gupaoedu.springaop.framework.proxy; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; /** * Created by Tom. */ public class GPClassLoader extends ClassLoader { private File classPathFile; public GPClassLoader(){ String classPath = GPClassLoader.class.getResource("").getPath(); this.classPathFile = new File(classPath); } @Override protected Class<?> findClass(String name) throws ClassNotFoundException { String className = GPClassLoader.class.getPackage().getName() + "." + name; if(classPathFile != null){ File classFile = new File(classPathFile,name.replaceAll("//.","/") + ".class"); if(classFile.exists()){ FileInputStream in = null; ByteArrayOutputStream out = null; try{ in = new FileInputStream(classFile); out = new ByteArrayOutputStream(); byte [] buff = new byte[1024]; int len; while ((len = in.read(buff)) != -1){ out.write(buff,0,len); } return defineClass(className,out.toByteArray(),0,out.size()); }catch (Exception e){ e.printStackTrace(); } } } return null; } }

GPProxy 动态生成代理类

package com.gupaoedu.springaop.framework.proxy; import javax.tools.JavaCompiler; import javax.tools.StandardJavaFileManager; import javax.tools.ToolProvider; import java.io.File; import java.io.FileWriter; import java.lang.reflect.Constructor; import java.lang.reflect.Method; import java.util.HashMap; import java.util.Map; /** * 用来生成源代码的工具类 * Created by Tom. */ public class GPProxy { public static final String ln = "/r/n"; public static Object newProxyInstance(GPClassLoader classLoader, Class<?> [] interfaces, GPInvocationHandler h){ try { //1、动态生成源代码.java文件 String src = generateSrc(interfaces); //2、Java文件输出磁盘 String filePath = GPProxy.class.getResource("").getPath(); // System.out.println(filePath); File f = new File(filePath + "$Proxy0.java"); FileWriter fw = new FileWriter(f); fw.write(src); fw.flush(); fw.close(); //3、把生成的.java文件编译成.class文件 JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); StandardJavaFileManager manage = compiler.getStandardFileManager(null,null,null); Iterable iterable = manage.getJavaFileObjects(f); JavaCompiler.CompilationTask task = compiler.getTask(null,manage,null,null,null,iterable); task.call(); manage.close(); //4、编译生成的.class文件加载到JVM中来 Class proxyClass = classLoader.findClass("$Proxy0"); Constructor c = proxyClass.getConstructor(GPInvocationHandler.class); f.delete(); //5、返回字节码重组以后的新的代理对象 return c.newInstance(h); }catch (Exception e){ e.printStackTrace(); } return null; } private static String generateSrc(Class<?>[] interfaces){ StringBuffer sb = new StringBuffer(); sb.append("package com.gupaoedu.springaop.framework.proxy;" + ln); sb.append("import java.lang.reflect.*;" + ln); sb.append("public class $Proxy0 implements " + interfaces[0].getName() + "{" + ln); sb.append("GPInvocationHandler h;" + ln); sb.append("public $Proxy0(GPInvocationHandler h) { " + ln); sb.append("this.h = h;"); sb.append("}" + ln); for (Method m : interfaces[0].getMethods()){ Class<?>[] params = m.getParameterTypes(); StringBuffer paramNames = new StringBuffer(); StringBuffer paramValues = new StringBuffer(); StringBuffer paramTypes = new StringBuffer(); for (int i = 0; i < params.length; i++) { Class clazz = params[i]; String type = clazz.getName(); String paramName = toLowerFirstCase(clazz.getSimpleName()); paramNames.append(type + " " + paramName); paramValues.append(paramName); paramTypes.append(clazz.getName() + ".class"); if(i > 0 && i < params.length-1){ paramNames.append(","); paramTypes.append(","); paramValues.append(","); } } sb.append("public " + m.getReturnType().getName() + " " + m.getName() + "(" + paramNames.toString() + ") {" + ln); sb.append("try{" + ln); sb.append("Method m = " + interfaces[0].getName() + ".class.getMethod(/"" + m.getName() + "/",new Class[]{" + paramTypes.toString() + "});" + ln); sb.append((hasReturnValue(m.getReturnType()) ? "return (" + m.getReturnType().getName() + ")" : "") + getCaseCode("this.h.invoke(this,m,new Object[]{" + paramValues + "})",m.getReturnType()) + ";" + ln); sb.append("}catch(Error _ex) { }"); sb.append("catch(Throwable e){" + ln); sb.append("throw new UndeclaredThrowableException(e);" + ln); sb.append("}"); sb.append(getReturnEmptyCode(m.getReturnType())); sb.append("}"); } sb.append("}" + ln); return sb.toString(); } private static Map<Class,Class> mappings = new HashMap<Class, Class>(); static { mappings.put(int.class,Integer.class); } private static String getReturnEmptyCode(Class<?> returnClass){ if(mappings.containsKey(returnClass)){ return "return 0;"; }else if(returnClass == void.class){ return ""; }else { return "return null;"; } } private static String getCaseCode(String code,Class<?> returnClass){ if(mappings.containsKey(returnClass)){ return "((" + mappings.get(returnClass).getName() + ")" + code + ")." + returnClass.getSimpleName() + "Value()"; } return code; } private static boolean hasReturnValue(Class<?> clazz){ return clazz != void.class; } private static String toLowerFirstCase(String src){ char [] chars = src.toCharArray(); chars[0] += 32; return String.valueOf(chars); } }

手写Spring AOP

GPAopConfig 保存配置信息

package com.gupaoedu.springaop.framework.config; import lombok.Data; /** * Created by Tom. */ @Data public class GPAopConfig { private String pointCut; private String aspectBefore; private String aspectAfter; private String aspectClass; private String aspectAfterThrow; private String aspectAfterThrowingName; }

GPAdvice通知接口

package com.gupaoedu.springaop.framework.aspect; import java.lang.reflect.Method; /** * 用于通知回调 */ public class GPAdvice { private Object aspect; private Method adviceMethod; private String throwName; public GPAdvice(Object aspect, Method adviceMethod) { this.aspect = aspect; this.adviceMethod = adviceMethod; } public Object getAspect() { return aspect; } public Method getAdviceMethod() { return adviceMethod; } public void setThrowName(String throwName) { this.throwName = throwName; } public String getThrowName() { return throwName; } }

GPJoinPoint切点

package com.gupaoedu.springaop.framework.aspect; import java.lang.reflect.Method; public interface GPJoinPoint { Object getThis(); Object[] getArguments(); Method getMethod(); void setUserAttribute(String key, Object value); Object getUserAttribute(String key); }

GPAdvisedSupport 解析切面配置

package com.gupaoedu.springaop.framework.aop; import com.gupaoedu.springaop.framework.aspect.GPAdvice; import com.gupaoedu.springaop.framework.config.GPAopConfig; import com.gupaoedu.springaop.framework.proxy.GPClassLoader; import java.lang.reflect.Method; import java.util.HashMap; import java.util.Map; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * Created by Tom. */ public class GPAdvisedSupport { private GPClassLoader classLoader; private Class<?> targetClass; private Object target; private GPAopConfig config; private Pattern pointCutClassPattern; private transient Map<Method, Map<String,GPAdvice>> methodCache; public GPAdvisedSupport(GPAopConfig config) { this.config = config; this.classLoader = new GPClassLoader(); } public Class<?> getTargetClass(){ return this.targetClass; } public Object getTarget(){ return this.target; } public Map<String,GPAdvice> getInterceptorsAndDynamicInterceptionAdvice(Method method, Class<?> targetClass) throws Exception{ Map<String,GPAdvice> cached = methodCache.get(method); if(cached == null){ Method m = targetClass.getMethod(method.getName(),method.getParameterTypes()); cached = methodCache.get(m); //底层逻辑，对代理方法进行一个兼容处理 this.methodCache.put(m,cached); } return cached; } public void setTargetClass(Class<?> targetClass) { this.targetClass = targetClass; parse(); } private void parse() { String pointCut = config.getPointCut() .replaceAll("//.","////.") .replaceAll("////.//*",".*") .replaceAll("//(","////(") .replaceAll("//)","////)"); //pointCut=public .* com.gupaoedu.vip.spring.demo.service..*Service..*(.*) //玩正则 String pointCutForClassRegex = pointCut.substring(0,pointCut.lastIndexOf("//(") - 4); pointCutClassPattern = Pattern.compile("class " + pointCutForClassRegex.substring( pointCutForClassRegex.lastIndexOf(" ") + 1)); try { methodCache = new HashMap<Method, Map<String,GPAdvice>>(); Pattern pattern = Pattern.compile(pointCut); Class aspectClass = Class.forName(this.config.getAspectClass()); Map<String,Method> aspectMethods = new HashMap<String,Method>(); for (Method m : aspectClass.getMethods()) { aspectMethods.put(m.getName(),m); } for (Method m : this.targetClass.getMethods()) { String methodString = m.toString(); if (methodString.contains("throws")) { methodString = methodString.substring(0, methodString.lastIndexOf("throws")).trim(); } Matcher matcher = pattern.matcher(methodString); if(matcher.matches()){ //执行器链 Map<String,GPAdvice> advices = new HashMap<String, GPAdvice>(); //把每一个方法包装成 MethodIterceptor //before if(!(null == config.getAspectBefore() || "".equals(config.getAspectBefore()))) { //创建一个Advivce advices.put("before",new GPAdvice(aspectClass.newInstance(),aspectMethods.get(config.getAspectBefore()))); } //after if(!(null == config.getAspectAfter() || "".equals(config.getAspectAfter()))) { //创建一个Advivce advices.put("after",new GPAdvice(aspectClass.newInstance(),aspectMethods.get(config.getAspectAfter()))); } //afterThrowing if(!(null == config.getAspectAfterThrow() || "".equals(config.getAspectAfterThrow()))) { //创建一个Advivce GPAdvice throwingAdvice = new GPAdvice(aspectClass.newInstance(),aspectMethods.get(config.getAspectAfterThrow())); throwingAdvice.setThrowName(config.getAspectAfterThrowingName()); advices.put("afterThrow",throwingAdvice); } methodCache.put(m,advices); } } }catch (Exception e){ e.printStackTrace(); } } public void setTarget(Object target) { this.target = target; } public boolean pointCutMatch() { return pointCutClassPattern.matcher(this.targetClass.toString()).matches(); } public GPClassLoader getClassLoader() { return classLoader; } }

GPJdkDynamicAopProxy实现动态代理

package com.gupaoedu.springaop.framework.aop; import com.gupaoedu.springaop.framework.aspect.GPAdvice; import com.gupaoedu.springaop.framework.proxy.GPClassLoader; import com.gupaoedu.springaop.framework.proxy.GPInvocationHandler; import com.gupaoedu.springaop.framework.proxy.GPProxy; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.Map; /** * Created by Tom. */ public class GPJdkDynamicAopProxy implements GPInvocationHandler { private GPAdvisedSupport advised; public GPJdkDynamicAopProxy(GPAdvisedSupport config){ this.advised = config; } public Object getProxy() { return getProxy(this.advised.getClassLoader()); } public Object getProxy(GPClassLoader classLoader) { return GPProxy.newProxyInstance(classLoader,this.advised.getTargetClass().getInterfaces(),this); } public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { Map<String,GPAdvice> advices = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method,this.advised.getTargetClass()); invokeAdvice(advices.get("before")); Object returnValue = null; try { returnValue = method.invoke(this.advised.getTarget(), args); }catch (Exception e){ invokeAdvice(advices.get("afterThrow")); } invokeAdvice(advices.get("after")); return returnValue; } private void invokeAdvice(GPAdvice advice){ try { advice.getAdviceMethod().invoke(advice.getAspect()); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } } }

测试代码

MemberServiceTest测试用例

package com.gupaoedu.springaop.service; import com.gupaoedu.springaop.demo.service.IMemberService; import com.gupaoedu.springaop.framework.GPApplicationContext; public class MemberServiceTest { public static void main(String[] args) { GPApplicationContext applicationContext = new GPApplicationContext(); IMemberService memberService = (IMemberService)applicationContext.getBean("memberService"); try { memberService.delete("1"); } catch (Exception e) { e.printStackTrace(); } } }