文章目录
1. 定义
代理模式是指为其他对象提供一种代理,以控制对这个对象的访问
代理对象在客服端和目标对象之间起到中介作用
2. 适用场景
- 保护目标对象
- 增强目标对象
3. 分类
- 静态代理
- JDK动态代理
- CGLIB动态代理
4. 静态代理
4.1 定义被代理类
package com.zhunongyun.toalibaba.designpatterns.proxy;
public interface Person {
/**
* 相亲
*/
void findLove();
}
package com.zhunongyun.toalibaba.designpatterns.proxy.staticproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
public class Son implements Person {
@Override
public void findLove() {
System.out.println("寻找伴侣要求: 肤白貌美大长腿");
}
}
4.2 代理类
package com.zhunongyun.toalibaba.designpatterns.proxy.staticproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
public class Father implements Person {
private Son son;
public Father(Son son) {
this.son = son;
}
@Override
public void findLove() {
this.before();
this.son.findLove();
this.after();
}
/**
* 增强目标对象
* 执行之前
*/
private void before(){
System.out.println("父亲正在帮儿子物色对象");
}
/**
* 增强目标对象
* 执行之后
*/
private void after(){
System.out.println("双方父母同意,确定关系");
}
}
4.3 测试类
package com.zhunongyun.toalibaba.designpatterns.proxy.staticproxy;
public class FatherProxyTest {
public static void main(String[] args) {
Father father = new Father(new Son());
father.findLove();
}
}
4.4 总结
- 被代理类Son当前只有findLove需求,后期增加findJob等更多的需求,Father也要增加对应的代码,不符合开闭原则
- 代理类与被代理类中间存在联系,代理类不能对所有的类服务
5. JDK动态代理
5.1 实现原理
- 拿到被代理类的引用,并且获取它的所有接口(反射获取)
- JDK Proxy类重新生成一个新的类,实现了被代理类所有接口的方法
- 动态生成java代码,把增强逻辑加入到新生成代码中
- 编译生成新的java代码的class文件
- 加载并重新运行新的class,得到的类就是全新类
5.2 被代理类
package com.zhunongyun.toalibaba.designpatterns.proxy;
public interface Person {
/**
* 相亲
*/
void findLove();
}
package com.zhunongyun.toalibaba.designpatterns.proxy;
public class Girl implements Person {
@Override
public void findLove() {
System.out.println("寻找对象要求:");
System.out.println("身高180");
System.out.println("有钱");
System.out.println("有六块腹肌");
}
}
5.3 代理类
package com.zhunongyun.toalibaba.designpatterns.proxy.dynamicproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
public class JDKMeipo implements InvocationHandler {
private Person person;
public Object getInstance(Person person) {
this.person = person;
Class<?> clazz = this.person.getClass();
return Proxy.newProxyInstance(clazz.getClassLoader(), clazz.getInterfaces(), this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
before();
Object object = method.invoke(this.person, args);
before();
return object;
}
/**
* 增强目标对象
* 执行之前
*/
private void before(){
System.out.println("我是媒婆,已经收到你的诉求");
System.out.println("正在物色对象");
}
/**
* 增强目标对象
* 执行之后
*/
private void after(){
System.out.println("相亲完成,确认双方意见");
}
}
5.4 测试类
package com.zhunongyun.toalibaba.designpatterns.proxy.dynamicproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Girl;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
import sun.misc.ProxyGenerator;
import java.io.FileOutputStream;
public class JDKProxyTest {
public static void main(String[] args) {
Person person = (Person) new JDKMeipo().getInstance(new Girl());
person.findLove();
}
}
5.5 总结
- 被代理类Girl在findLove功能的基础上增加其他需求,代理类JDKMeiPo不需要修改代码
- 代理类JDKMeiPo不仅可以代理Girl类,也可以代理其他类
5.6 代理类生成新的类
-
在代理类JDKMeipo中传入Gir类’Person person = (Person) new JDKMeipo().getInstance(new Girl());’, 得到Person类是一个全新的类$Proxy0
-
把 Proxy0.class中, 可以看到这个$Proxy类的代码
package com.zhunongyun.toalibaba.designpatterns.proxy.dynamicproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Girl;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
import sun.misc.ProxyGenerator;
import java.io.FileOutputStream;
public class JDKProxyTest {
public static void main(String[] args) {
Person person = (Person) new JDKMeipo().getInstance(new Girl());
person.findLove();
byte[] bytes = ProxyGenerator.generateProxyClass("$Proxy0", new Class[]{Person.class});
try (FileOutputStream fileOutputStream = new FileOutputStream("$Proxy0.class")) {
fileOutputStream.write(bytes);
} catch (Exception e) {
e.printStackTrace();
}
}
}
可以看到Method m3
对应就是Girl类中的findLove方法
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
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 Person {
private static Method m1;
private static Method m3;
private static Method m2;
private static Method m0;
public $Proxy0(InvocationHandler var1) throws {
super(var1);
}
public final boolean equals(Object var1) throws {
try {
return (Boolean)super.h.invoke(this, m1, new Object[]{var1});
} catch (RuntimeException | Error var3) {
throw var3;
} catch (Throwable var4) {
throw new UndeclaredThrowableException(var4);
}
}
public final void findLove() throws {
try {
super.h.invoke(this, m3, (Object[])null);
} catch (RuntimeException | Error var2) {
throw var2;
} catch (Throwable var3) {
throw new UndeclaredThrowableException(var3);
}
}
public final String toString() throws {
try {
return (String)super.h.invoke(this, m2, (Object[])null);
} catch (RuntimeException | Error var2) {
throw var2;
} catch (Throwable var3) {
throw new UndeclaredThrowableException(var3);
}
}
public final int hashCode() throws {
try {
return (Integer)super.h.invoke(this, m0, (Object[])null);
} catch (RuntimeException | Error var2) {
throw var2;
} catch (Throwable var3) {
throw new UndeclaredThrowableException(var3);
}
}
static {
try {
m1 = Class.forName("java.lang.Object").getMethod("equals", Class.forName("java.lang.Object"));
m3 = Class.forName("com.zhunongyun.toalibaba.designpatterns.proxy.Person").getMethod("findLove");
m2 = Class.forName("java.lang.Object").getMethod("toString");
m0 = Class.forName("java.lang.Object").getMethod("hashCode");
} catch (NoSuchMethodException var2) {
throw new NoSuchMethodError(var2.getMessage());
} catch (ClassNotFoundException var3) {
throw new NoClassDefFoundError(var3.getMessage());
}
}
}
6. 自己实现JDK动态代理
6.1 实现原理
- 拿到被代理类的引用,并且获取它的所有接口(反射获取)
- JDK Proxy类重新生成一个新的类,实现了被代理类所有接口的方法
- 动态生成java代码,把增强逻辑加入到新生成代码中
- 编译生成新的java代码的class文件
- 加载并重新运行新的class,得到的类就是全新类
6.1 被代理类
package com.zhunongyun.toalibaba.designpatterns.proxy;
public class Girl implements Person {
@Override
public void findLove() {
System.out.println("寻找对象要求:");
System.out.println("身高180");
System.out.println("有钱");
System.out.println("有六块腹肌");
}
}
6.2 代理类
package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
import java.lang.reflect.Method;
public class MyMeipo implements MyInvocationHandler {
private Person person;
public Object getInstance(Person person) {
this.person = person;
Class<?> clazz = this.person.getClass();
return MyProxy.newProxyInstance(new MyClassLoader(), clazz.getInterfaces(), this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) {
Object object = null;
try {
before();
object = method.invoke(this.person, args);
after();
} catch (Exception e) {
e.printStackTrace();
}
return object;
}
/**
* 增强目标对象
* 执行之前
*/
private void before(){
System.out.println("我是媒婆,已经收到你的诉求");
System.out.println("正在物色对象");
}
/**
* 增强目标对象
* 执行之后
*/
private void after(){
System.out.println("相亲完成,确认双方意见");
}
}
6.3 自定义类加载器ClassLoader
package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
public class MyClassLoader extends ClassLoader {
private File classPathFile;
public MyClassLoader() {
String classPath = MyClassLoader.class.getResource("").getPath();
classPathFile = new File(classPath);
}
@Override
public Class<?> findClass(String name) throws ClassNotFoundException {
String className = MyClassLoader.class.getPackage().getName() + "." +name;
if (classPathFile != null) {
File file = new File(classPathFile, name + ".class");
try (FileInputStream fileInputStream = new FileInputStream(file);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();) {
byte[] buff = new byte[1024];
int len;
while((len=fileInputStream.read(buff))!=-1){
outputStream.write(buff, 0, len);
}
return defineClass(className, outputStream.toByteArray(), 0, outputStream.size());
}catch(Exception e){
e.printStackTrace();
}
}
return null;
}
}
6.4 自定义InvacationHandler
package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;
import java.lang.reflect.Method;
public interface MyInvocationHandler {
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable;
}
6.5 自定义代理类Proxy
package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;
import javax.tools.*;
import java.io.File;
import java.io.FileWriter;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
public class MyProxy {
public static final String LN = "\r\n";
public static Object newProxyInstance(MyClassLoader myClassLoader, Class<?>[] interfaces, MyInvocationHandler h) {
try{
// 1 动态生成java源码
String src = generateSrc(interfaces);
// 2 将源码输出到java文件中
String filePath = MyProxy.class.getResource("").getPath();
File f = new File(filePath + "$Proxy0.java");
FileWriter fw = new FileWriter(f);
fw.write(src);
fw.flush();
fw.close();
//3、将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、将class加载进jvm
Class proxyClass=myClassLoader.findClass("$Proxy0");
f.delete();
//5、返回代理类对象
Constructor constructor = proxyClass.getConstructor(MyInvocationHandler.class);
return constructor.newInstance(h);
}catch(Exception e){
e.printStackTrace();
}
return null;
}
private static String generateSrc(Class<?>[] interfaces) {
// TODO Auto-generated method stub
StringBuffer sb = new StringBuffer();
sb.append("package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;").append(LN);
sb.append("import java.lang.reflect.Method;").append(LN);
sb.append("public class $Proxy0 implements " + interfaces[0].getName() + "{").append(LN);
sb.append("private MyInvocationHandler h;").append(LN);
sb.append("public $Proxy0(MyInvocationHandler h) { ").append(LN);
sb.append("this.h = h;").append(LN);
sb.append("}").append(LN);
for (Method m : interfaces[0].getMethods()) {
sb.append("public " + m.getReturnType().getName() + " " + m.getName() + "() {").append(LN);
sb.append("try{").append(LN);
sb.append("Method m = " + interfaces[0].getName() + ".class.getMethod(\"" + m.getName() + "\",new Class[]{});").append(LN);
sb.append("this.h.invoke(this,m,null);").append(LN);
sb.append("}catch(Throwable e){").append(LN);
sb.append("e.printStackTrace();").append(LN);
sb.append("}").append(LN);
sb.append("}").append(LN);
}
sb.append("}").append(LN);
return sb.toString();
}
}
6.6 测试类
package com.zhunongyun.toalibaba.designpatterns.proxy.myproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.Person;
import com.zhunongyun.toalibaba.designpatterns.proxy.Girl;
public class MyProxyTest {
public static void main(String[] args) {
Person person = (Person) new MyMeipo().getInstance(new Girl());
person.findLove();
}
}
7. CGlib动态代理
- CGlib通过继承被代理类,并覆盖被代理类的方法
- CGlib可以代理任意一个普通的类,没有任何要求
- CGlib生成代理逻辑更加复杂,调用效率更高,生成一个包含了所有的逻辑的FastClass,不再需要反射调用
- CGlib代理有坑,不能代理final方法
7.1 被代理类
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
public class NewGirl {
public void findLove() {
System.out.println("寻找对象要求:");
System.out.println("身高180");
System.out.println("有钱");
System.out.println("有六块腹肌");
}
}
7.2 CGLib代理类
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
public class CGlibMeipo implements MethodInterceptor {
public Object getInstance(Class<?> clazz) throws Exception {
Enhancer enhancer = new Enhancer();
enhancer.setSuperclass(clazz);
enhancer.setCallback(this);
return enhancer.create();
}
@Override
public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
before();
Object object = methodProxy.invokeSuper(o, objects);
after();
return object;
}
/**
* 增强目标对象
* 执行之前
*/
private void before(){
System.out.println("我是媒婆,已经收到你的诉求");
System.out.println("正在物色对象");
}
/**
* 增强目标对象
* 执行之后
*/
private void after(){
System.out.println("相亲完成,确认双方意见");
}
}
7.3 测试类
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
import org.springframework.cglib.core.DebuggingClassWriter;
public class CGlibProxyTest {
public static void main(String[] args) {
// 把CGlib生成的代码输出到文件中
System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, CGlibProxyTest.class.getResource("").getPath());
try {
NewGirl newGirl = (NewGirl) new CGlibMeipo().getInstance(NewGirl.class);
newGirl.findLove();
} catch (Exception e) {
e.printStackTrace();
}
}
}
7.4 CGlib生成的代码分析
在CGlib代理测试类中输出生成的代码到磁盘文件, 生成了以下三个class文件
- NewGirl 2a25c1b4 2393400d.class
- NewGirl 2a25c1b4.class
- NewGirl 1cf5df8b.class
反编译这三个class文件详情如下
7.4.1 NewGirl$$EnhancerByCGLIB$$2a25c1b4$$FastClassByCGLIB$$2393400d.class
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
import com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy.NewGirl..EnhancerByCGLIB..2a25c1b4;
import java.lang.reflect.InvocationTargetException;
import org.springframework.cglib.core.Signature;
import org.springframework.cglib.proxy.Callback;
import org.springframework.cglib.reflect.FastClass;
public class NewGirl$$EnhancerByCGLIB$$2a25c1b4$$FastClassByCGLIB$$2393400d extends FastClass {
public NewGirl$$EnhancerByCGLIB$$2a25c1b4$$FastClassByCGLIB$$2393400d(Class var1) {
super(var1);
}
public int getIndex(Signature var1) {
String var10000 = var1.toString();
switch(var10000.hashCode()) {
case -1882565338:
if (var10000.equals("CGLIB$equals$1(Ljava/lang/Object;)Z")) {
return 17;
}
break;
case -1870561232:
if (var10000.equals("CGLIB$findMethodProxy(Lorg/springframework/cglib/core/Signature;)Lorg/springframework/cglib/proxy/MethodProxy;")) {
return 14;
}
break;
case -1745842178:
if (var10000.equals("setCallbacks([Lorg/springframework/cglib/proxy/Callback;)V")) {
return 9;
}
break;
case -1641413109:
if (var10000.equals("newInstance([Lorg/springframework/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 4;
}
break;
case -1457535688:
if (var10000.equals("CGLIB$STATICHOOK1()V")) {
return 15;
}
break;
case -1411842725:
if (var10000.equals("CGLIB$hashCode$3()I")) {
return 19;
}
break;
case -1034266769:
if (var10000.equals("CGLIB$SET_STATIC_CALLBACKS([Lorg/springframework/cglib/proxy/Callback;)V")) {
return 10;
}
break;
case -1025895669:
if (var10000.equals("CGLIB$SET_THREAD_CALLBACKS([Lorg/springframework/cglib/proxy/Callback;)V")) {
return 11;
}
break;
case -988317324:
if (var10000.equals("newInstance([Ljava/lang/Class;[Ljava/lang/Object;[Lorg/springframework/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 5;
}
break;
case -508378822:
if (var10000.equals("clone()Ljava/lang/Object;")) {
return 3;
}
break;
case 610042816:
if (var10000.equals("newInstance(Lorg/springframework/cglib/proxy/Callback;)Ljava/lang/Object;")) {
return 6;
}
break;
case 1096387995:
if (var10000.equals("CGLIB$findLove$0()V")) {
return 16;
}
break;
case 1132856532:
if (var10000.equals("getCallbacks()[Lorg/springframework/cglib/proxy/Callback;")) {
return 13;
}
break;
case 1192015562:
if (var10000.equals("findLove()V")) {
return 7;
}
break;
case 1246779367:
if (var10000.equals("setCallback(ILorg/springframework/cglib/proxy/Callback;)V")) {
return 8;
}
break;
case 1306468936:
if (var10000.equals("CGLIB$toString$2()Ljava/lang/String;")) {
return 18;
}
break;
case 1364367423:
if (var10000.equals("getCallback(I)Lorg/springframework/cglib/proxy/Callback;")) {
return 12;
}
break;
case 1800494055:
if (var10000.equals("CGLIB$clone$4()Ljava/lang/Object;")) {
return 20;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return 0;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return 1;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return 2;
}
}
return -1;
}
public int getIndex(String var1, Class[] var2) {
switch(var1.hashCode()) {
case -1776922004:
if (var1.equals("toString")) {
switch(var2.length) {
case 0:
return 1;
}
}
break;
case -1295482945:
if (var1.equals("equals")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 0;
}
}
}
break;
case -1053468136:
if (var1.equals("getCallbacks")) {
switch(var2.length) {
case 0:
return 13;
}
}
break;
case -679433013:
if (var1.equals("findLove")) {
switch(var2.length) {
case 0:
return 7;
}
}
break;
case -331698278:
if (var1.equals("CGLIB$findLove$0")) {
switch(var2.length) {
case 0:
return 16;
}
}
break;
case -124978609:
if (var1.equals("CGLIB$equals$1")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 17;
}
}
}
break;
case -60403779:
if (var1.equals("CGLIB$SET_STATIC_CALLBACKS")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lorg.springframework.cglib.proxy.Callback;")) {
return 10;
}
}
}
break;
case -29025555:
if (var1.equals("CGLIB$hashCode$3")) {
switch(var2.length) {
case 0:
return 19;
}
}
break;
case 85179481:
if (var1.equals("CGLIB$SET_THREAD_CALLBACKS")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lorg.springframework.cglib.proxy.Callback;")) {
return 11;
}
}
}
break;
case 94756189:
if (var1.equals("clone")) {
switch(var2.length) {
case 0:
return 3;
}
}
break;
case 147696667:
if (var1.equals("hashCode")) {
switch(var2.length) {
case 0:
return 2;
}
}
break;
case 161998109:
if (var1.equals("CGLIB$STATICHOOK1")) {
switch(var2.length) {
case 0:
return 15;
}
}
break;
case 495524492:
if (var1.equals("setCallbacks")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("[Lorg.springframework.cglib.proxy.Callback;")) {
return 9;
}
}
}
break;
case 1154623345:
if (var1.equals("CGLIB$findMethodProxy")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("org.springframework.cglib.core.Signature")) {
return 14;
}
}
}
break;
case 1543336189:
if (var1.equals("CGLIB$toString$2")) {
switch(var2.length) {
case 0:
return 18;
}
}
break;
case 1811874389:
if (var1.equals("newInstance")) {
switch(var2.length) {
case 1:
String var10001 = var2[0].getName();
switch(var10001.hashCode()) {
case -1997738671:
if (var10001.equals("[Lorg.springframework.cglib.proxy.Callback;")) {
return 4;
}
break;
case 1364160985:
if (var10001.equals("org.springframework.cglib.proxy.Callback")) {
return 6;
}
}
case 2:
default:
break;
case 3:
if (var2[0].getName().equals("[Ljava.lang.Class;") && var2[1].getName().equals("[Ljava.lang.Object;") && var2[2].getName().equals("[Lorg.springframework.cglib.proxy.Callback;")) {
return 5;
}
}
}
break;
case 1817099975:
if (var1.equals("setCallback")) {
switch(var2.length) {
case 2:
if (var2[0].getName().equals("int") && var2[1].getName().equals("org.springframework.cglib.proxy.Callback")) {
return 8;
}
}
}
break;
case 1905679803:
if (var1.equals("getCallback")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("int")) {
return 12;
}
}
}
break;
case 1951977610:
if (var1.equals("CGLIB$clone$4")) {
switch(var2.length) {
case 0:
return 20;
}
}
}
return -1;
}
public int getIndex(Class[] var1) {
switch(var1.length) {
case 0:
return 0;
default:
return -1;
}
}
public Object invoke(int var1, Object var2, Object[] var3) throws InvocationTargetException {
2a25c1b4 var10000 = (2a25c1b4)var2;
int var10001 = var1;
try {
switch(var10001) {
case 0:
return new Boolean(var10000.equals(var3[0]));
case 1:
return var10000.toString();
case 2:
return new Integer(var10000.hashCode());
case 3:
return var10000.clone();
case 4:
return var10000.newInstance((Callback[])var3[0]);
case 5:
return var10000.newInstance((Class[])var3[0], (Object[])var3[1], (Callback[])var3[2]);
case 6:
return var10000.newInstance((Callback)var3[0]);
case 7:
var10000.findLove();
return null;
case 8:
var10000.setCallback(((Number)var3[0]).intValue(), (Callback)var3[1]);
return null;
case 9:
var10000.setCallbacks((Callback[])var3[0]);
return null;
case 10:
2a25c1b4.CGLIB$SET_STATIC_CALLBACKS((Callback[])var3[0]);
return null;
case 11:
2a25c1b4.CGLIB$SET_THREAD_CALLBACKS((Callback[])var3[0]);
return null;
case 12:
return var10000.getCallback(((Number)var3[0]).intValue());
case 13:
return var10000.getCallbacks();
case 14:
return 2a25c1b4.CGLIB$findMethodProxy((Signature)var3[0]);
case 15:
2a25c1b4.CGLIB$STATICHOOK1();
return null;
case 16:
var10000.CGLIB$findLove$0();
return null;
case 17:
return new Boolean(var10000.CGLIB$equals$1(var3[0]));
case 18:
return var10000.CGLIB$toString$2();
case 19:
return new Integer(var10000.CGLIB$hashCode$3());
case 20:
return var10000.CGLIB$clone$4();
}
} catch (Throwable var4) {
throw new InvocationTargetException(var4);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public Object newInstance(int var1, Object[] var2) throws InvocationTargetException {
2a25c1b4 var10000 = new 2a25c1b4;
2a25c1b4 var10001 = var10000;
int var10002 = var1;
try {
switch(var10002) {
case 0:
var10001.<init>();
return var10000;
}
} catch (Throwable var3) {
throw new InvocationTargetException(var3);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public int getMaxIndex() {
return 20;
}
}
7.4.1 NewGirl$$EnhancerByCGLIB$$2a25c1b4.class
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
import java.lang.reflect.Method;
import org.springframework.cglib.core.ReflectUtils;
import org.springframework.cglib.core.Signature;
import org.springframework.cglib.proxy.Callback;
import org.springframework.cglib.proxy.Factory;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
public class NewGirl$$EnhancerByCGLIB$$2a25c1b4 extends NewGirl implements Factory {
private boolean CGLIB$BOUND;
public static Object CGLIB$FACTORY_DATA;
private static final ThreadLocal CGLIB$THREAD_CALLBACKS;
private static final Callback[] CGLIB$STATIC_CALLBACKS;
private MethodInterceptor CGLIB$CALLBACK_0;
private static Object CGLIB$CALLBACK_FILTER;
private static final Method CGLIB$findLove$0$Method;
private static final MethodProxy CGLIB$findLove$0$Proxy;
private static final Object[] CGLIB$emptyArgs;
private static final Method CGLIB$equals$1$Method;
private static final MethodProxy CGLIB$equals$1$Proxy;
private static final Method CGLIB$toString$2$Method;
private static final MethodProxy CGLIB$toString$2$Proxy;
private static final Method CGLIB$hashCode$3$Method;
private static final MethodProxy CGLIB$hashCode$3$Proxy;
private static final Method CGLIB$clone$4$Method;
private static final MethodProxy CGLIB$clone$4$Proxy;
static void CGLIB$STATICHOOK1() {
CGLIB$THREAD_CALLBACKS = new ThreadLocal();
CGLIB$emptyArgs = new Object[0];
Class var0 = Class.forName("com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy.NewGirl$$EnhancerByCGLIB$$2a25c1b4");
Class var1;
Method[] var10000 = ReflectUtils.findMethods(new String[]{"equals", "(Ljava/lang/Object;)Z", "toString", "()Ljava/lang/String;", "hashCode", "()I", "clone", "()Ljava/lang/Object;"}, (var1 = Class.forName("java.lang.Object")).getDeclaredMethods());
CGLIB$equals$1$Method = var10000[0];
CGLIB$equals$1$Proxy = MethodProxy.create(var1, var0, "(Ljava/lang/Object;)Z", "equals", "CGLIB$equals$1");
CGLIB$toString$2$Method = var10000[1];
CGLIB$toString$2$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/String;", "toString", "CGLIB$toString$2");
CGLIB$hashCode$3$Method = var10000[2];
CGLIB$hashCode$3$Proxy = MethodProxy.create(var1, var0, "()I", "hashCode", "CGLIB$hashCode$3");
CGLIB$clone$4$Method = var10000[3];
CGLIB$clone$4$Proxy = MethodProxy.create(var1, var0, "()Ljava/lang/Object;", "clone", "CGLIB$clone$4");
CGLIB$findLove$0$Method = ReflectUtils.findMethods(new String[]{"findLove", "()V"}, (var1 = Class.forName("com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy.NewGirl")).getDeclaredMethods())[0];
CGLIB$findLove$0$Proxy = MethodProxy.create(var1, var0, "()V", "findLove", "CGLIB$findLove$0");
}
final void CGLIB$findLove$0() {
super.findLove();
}
public final void findLove() {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
if (var10000 != null) {
var10000.intercept(this, CGLIB$findLove$0$Method, CGLIB$emptyArgs, CGLIB$findLove$0$Proxy);
} else {
super.findLove();
}
}
final boolean CGLIB$equals$1(Object var1) {
return super.equals(var1);
}
public final boolean equals(Object var1) {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
if (var10000 != null) {
Object var2 = var10000.intercept(this, CGLIB$equals$1$Method, new Object[]{var1}, CGLIB$equals$1$Proxy);
return var2 == null ? false : (Boolean)var2;
} else {
return super.equals(var1);
}
}
final String CGLIB$toString$2() {
return super.toString();
}
public final String toString() {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
return var10000 != null ? (String)var10000.intercept(this, CGLIB$toString$2$Method, CGLIB$emptyArgs, CGLIB$toString$2$Proxy) : super.toString();
}
final int CGLIB$hashCode$3() {
return super.hashCode();
}
public final int hashCode() {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
if (var10000 != null) {
Object var1 = var10000.intercept(this, CGLIB$hashCode$3$Method, CGLIB$emptyArgs, CGLIB$hashCode$3$Proxy);
return var1 == null ? 0 : ((Number)var1).intValue();
} else {
return super.hashCode();
}
}
final Object CGLIB$clone$4() throws CloneNotSupportedException {
return super.clone();
}
protected final Object clone() throws CloneNotSupportedException {
MethodInterceptor var10000 = this.CGLIB$CALLBACK_0;
if (var10000 == null) {
CGLIB$BIND_CALLBACKS(this);
var10000 = this.CGLIB$CALLBACK_0;
}
return var10000 != null ? var10000.intercept(this, CGLIB$clone$4$Method, CGLIB$emptyArgs, CGLIB$clone$4$Proxy) : super.clone();
}
public static MethodProxy CGLIB$findMethodProxy(Signature var0) {
String var10000 = var0.toString();
switch(var10000.hashCode()) {
case -508378822:
if (var10000.equals("clone()Ljava/lang/Object;")) {
return CGLIB$clone$4$Proxy;
}
break;
case 1192015562:
if (var10000.equals("findLove()V")) {
return CGLIB$findLove$0$Proxy;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return CGLIB$equals$1$Proxy;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return CGLIB$toString$2$Proxy;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return CGLIB$hashCode$3$Proxy;
}
}
return null;
}
public NewGirl$$EnhancerByCGLIB$$2a25c1b4() {
CGLIB$BIND_CALLBACKS(this);
}
public static void CGLIB$SET_THREAD_CALLBACKS(Callback[] var0) {
CGLIB$THREAD_CALLBACKS.set(var0);
}
public static void CGLIB$SET_STATIC_CALLBACKS(Callback[] var0) {
CGLIB$STATIC_CALLBACKS = var0;
}
private static final void CGLIB$BIND_CALLBACKS(Object var0) {
NewGirl$$EnhancerByCGLIB$$2a25c1b4 var1 = (NewGirl$$EnhancerByCGLIB$$2a25c1b4)var0;
if (!var1.CGLIB$BOUND) {
var1.CGLIB$BOUND = true;
Object var10000 = CGLIB$THREAD_CALLBACKS.get();
if (var10000 == null) {
var10000 = CGLIB$STATIC_CALLBACKS;
if (var10000 == null) {
return;
}
}
var1.CGLIB$CALLBACK_0 = (MethodInterceptor)((Callback[])var10000)[0];
}
}
public Object newInstance(Callback[] var1) {
CGLIB$SET_THREAD_CALLBACKS(var1);
NewGirl$$EnhancerByCGLIB$$2a25c1b4 var10000 = new NewGirl$$EnhancerByCGLIB$$2a25c1b4();
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
}
public Object newInstance(Callback var1) {
CGLIB$SET_THREAD_CALLBACKS(new Callback[]{var1});
NewGirl$$EnhancerByCGLIB$$2a25c1b4 var10000 = new NewGirl$$EnhancerByCGLIB$$2a25c1b4();
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
}
public Object newInstance(Class[] var1, Object[] var2, Callback[] var3) {
CGLIB$SET_THREAD_CALLBACKS(var3);
NewGirl$$EnhancerByCGLIB$$2a25c1b4 var10000 = new NewGirl$$EnhancerByCGLIB$$2a25c1b4;
switch(var1.length) {
case 0:
var10000.<init>();
CGLIB$SET_THREAD_CALLBACKS((Callback[])null);
return var10000;
default:
throw new IllegalArgumentException("Constructor not found");
}
}
public Callback getCallback(int var1) {
CGLIB$BIND_CALLBACKS(this);
MethodInterceptor var10000;
switch(var1) {
case 0:
var10000 = this.CGLIB$CALLBACK_0;
break;
default:
var10000 = null;
}
return var10000;
}
public void setCallback(int var1, Callback var2) {
switch(var1) {
case 0:
this.CGLIB$CALLBACK_0 = (MethodInterceptor)var2;
default:
}
}
public Callback[] getCallbacks() {
CGLIB$BIND_CALLBACKS(this);
return new Callback[]{this.CGLIB$CALLBACK_0};
}
public void setCallbacks(Callback[] var1) {
this.CGLIB$CALLBACK_0 = (MethodInterceptor)var1[0];
}
static {
CGLIB$STATICHOOK1();
}
}
7.4.3 NewGirl$$FastClassByCGLIB$$1cf5df8b.class
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
package com.zhunongyun.toalibaba.designpatterns.proxy.cglibproxy;
import java.lang.reflect.InvocationTargetException;
import org.springframework.cglib.core.Signature;
import org.springframework.cglib.reflect.FastClass;
public class NewGirl$$FastClassByCGLIB$$1cf5df8b extends FastClass {
public NewGirl$$FastClassByCGLIB$$1cf5df8b(Class var1) {
super(var1);
}
public int getIndex(Signature var1) {
String var10000 = var1.toString();
switch(var10000.hashCode()) {
case 1192015562:
if (var10000.equals("findLove()V")) {
return 0;
}
break;
case 1826985398:
if (var10000.equals("equals(Ljava/lang/Object;)Z")) {
return 1;
}
break;
case 1913648695:
if (var10000.equals("toString()Ljava/lang/String;")) {
return 2;
}
break;
case 1984935277:
if (var10000.equals("hashCode()I")) {
return 3;
}
}
return -1;
}
public int getIndex(String var1, Class[] var2) {
switch(var1.hashCode()) {
case -1776922004:
if (var1.equals("toString")) {
switch(var2.length) {
case 0:
return 2;
}
}
break;
case -1295482945:
if (var1.equals("equals")) {
switch(var2.length) {
case 1:
if (var2[0].getName().equals("java.lang.Object")) {
return 1;
}
}
}
break;
case -679433013:
if (var1.equals("findLove")) {
switch(var2.length) {
case 0:
return 0;
}
}
break;
case 147696667:
if (var1.equals("hashCode")) {
switch(var2.length) {
case 0:
return 3;
}
}
}
return -1;
}
public int getIndex(Class[] var1) {
switch(var1.length) {
case 0:
return 0;
default:
return -1;
}
}
public Object invoke(int var1, Object var2, Object[] var3) throws InvocationTargetException {
NewGirl var10000 = (NewGirl)var2;
int var10001 = var1;
try {
switch(var10001) {
case 0:
var10000.findLove();
return null;
case 1:
return new Boolean(var10000.equals(var3[0]));
case 2:
return var10000.toString();
case 3:
return new Integer(var10000.hashCode());
}
} catch (Throwable var4) {
throw new InvocationTargetException(var4);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public Object newInstance(int var1, Object[] var2) throws InvocationTargetException {
NewGirl var10000 = new NewGirl;
NewGirl var10001 = var10000;
int var10002 = var1;
try {
switch(var10002) {
case 0:
var10001.<init>();
return var10000;
}
} catch (Throwable var3) {
throw new InvocationTargetException(var3);
}
throw new IllegalArgumentException("Cannot find matching method/constructor");
}
public int getMaxIndex() {
return 3;
}
}
8. 总结
8.1 CGlib动态代理和JDK动态代理对比
两种动态代理都是通过生成新的类,去实现增强被代理类代码逻辑的功能
- JDK动态代理采用实现被代理对象接口
- CGlib动态代理采用继承被代理对象,并覆盖父类方法
- JDK动态代理对于用户而言,必须要有一个接口实现,目标类相对来说复杂
- CGlib动态代理可以代理任意一个普通的对象,没有任何要求
- JDK动态代理生成代理的逻辑简单,执行效率相对较低,每次都要反射动态调用
- CGlib生成代理逻辑更加复杂,调用效率更高,生成一个包含了所有的逻辑的FastClass,不再需要反射调用
- CGlib代理有坑,不能代理final方法
8.2 代理模式优点
- 代理模式能将代理对象与真实被调用的目标对象分离
- 一定程度上降低了系统耦合程度,易于扩展
- 代理模式起到了保护目标对象的作用
- 增强目标对象的职责
8.2 代理模式缺点
- 代理模式会造成系统设计中类的数量增加
- 在客户端和目标对象之间增加了一个代理对象,会造成请求处理速度变慢
- 增加了系统的复杂度
9. Spring中动态代理选择
- 当Bean有实现接口时,Spring就会用JDK的动态代理
- 当Bean没有实现接口时,Spring会选择CGlib
- Spring可以通过配置强制使用CGlib,只需在Spring的配置文件中加入如下代码
<aop:aspectj-autoproxy proxy-target-class="true">