核心逻辑实例：
1 String className = "com.sun.$Proxy";
2 int accessFlags = Modifier.PUBLIC | Modifier.FINAL;
3
4 Class[] cls = new Class[]{Executor.class};
5
6 byte[] bytes = ProxyGenerator.generateProxyClass(className, cls, accessFlags);
7
8 System.out.println("byteLen: " + bytes.length);
9 Path path = Paths.get("D:\misc\Proxy.class");
10
11 try {
12 Files.createFile(path);
13 OutputStream outputStream = Files.newOutputStream(path, StandardOpenOption.WRITE);
14 outputStream.write(bytes);
15 outputStream.close();
16 } catch (IOException e) {
17 e.printStackTrace();
18 }这里将byte[] 写入文件，二进制文件Proxy.class 反编译后类似：
1 // 2 // Source code recreated from a .class file by IntelliJ IDEA
3 // (powered by Fernflower decompiler)
4 //
5
6 package com.sun;
7
8 import indi.joynic.actscase.gen.aopalliance.Executor;
9 import java.lang.reflect.InvocationHandler;
10 import java.lang.reflect.Method;
11 import java.lang.reflect.Proxy;
12 import java.lang.reflect.UndeclaredThrowableException;
13
14 public final class $Proxy extends Proxy implements Executor {
15 private static Method m1;
16 private static Method m2;
17 private static Method m3;
18 private static Method m0;
19
20 public $Proxy(InvocationHandler var1) throws {
21 super(var1);
22 }
23
24 public final boolean equals(Object var1) throws {
25 try {
26 return (Boolean)super.h.invoke(this, m1, new Object[]{var1});
27 } catch (RuntimeException | Error var3) {
28 throw var3;
29 } catch (Throwable var4) {
30 throw new UndeclaredThrowableException(var4);
31 }
32 }
33
34 public final String toString() throws {
35 try {
36 return (String)super.h.invoke(this, m2, (Object[])null);
37 } catch (RuntimeException | Error var2) {
38 throw var2;
39 } catch (Throwable var3) {
40 throw new UndeclaredThrowableException(var3);
41 }
42 }
43
44 public final char execute() throws {
45 try {
46 return (Character)super.h.invoke(this, m3, (Object[])null);
47 } catch (RuntimeException | Error var2) {
48 throw var2;
49 } catch (Throwable var3) {
50 throw new UndeclaredThrowableException(var3);
51 }
52 }
53
54 public final int hashCode() throws {
55 try {
56 return (Integer)super.h.invoke(this, m0, (Object[])null);
57 } catch (RuntimeException | Error var2) {
58 throw var2;
59 } catch (Throwable var3) {
60 throw new UndeclaredThrowableException(var3);
61 }
62 }
63
64 static {
65 try {
66 m1 = Class.forName("java.lang.Object").getMethod("equals", Class.forName("java.lang.Object"));
67 m2 = Class.forName("java.lang.Object").getMethod("toString");
68 m3 = Class.forName("indi.joynic.actscase.gen.aopalliance.Executor").getMethod("execute");
69 m0 = Class.forName("java.lang.Object").getMethod("hashCode");
70 } catch (NoSuchMethodException var2) {
71 throw new NoSuchMethodError(var2.getMessage());
72 } catch (ClassNotFoundException var3) {
73 throw new NoClassDefFoundError(var3.getMessage());
74 }
75 }
76 }生成了一个新的Proxy代理子类，可以看到实际返回的类定义写入了 hashCode() 、toString()、equals()和 用户接口方法 execute(), 而且将方法调用委派给用户指定的 InvocationHandler。
所以本质上来说“动态代理”仍旧是“静态代理”，“动态”表现在不用修改代码的情况下运行时通过“魔改”，然后“偷梁换柱”的方式返回给用户代理对象；
对用户来说，调用返回的代理对象本身就实现了用户接口 （implements Executor）。
从用户的角度语义上讲即为：“塞给java.lang.reflect.Proxy任意接口和目标对象，Poxy都能给出用户指定增强目标对象接口方法逻辑的代理对象”；
如果不制定具体是哪个接口，java.lang.reflect.Proxy 无法得知在从何处抽取出接口方法生成class byte数组。
无接口AOP增强类方法就要依靠cglib之类工具了。
