Java 创建动态类和查看方法列表信息的实例_Java教程

Java 创建动态类和查看方法列表信息的实例

2020-11-12 17:22Java之家 Java教程

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Java 创建动态类和查看方法列表信息的实例

Sample code :

									import java.lang.reflect.Constructor; 

									import java.lang.reflect.InvocationHandler; 

									import java.lang.reflect.Method; 

									import java.lang.reflect.Proxy; 

									import java.lang.reflect.Type; 

									import java.util.ArrayList; 

									import java.util.Collection; 

									public class ProxyTest { 

									  public static void main(String[] args) throws Exception { 

									    // TODO Auto-generated method stub 

									    Class clazzProxy = Proxy.getProxyClass(Collection.class.getClassLoader(), Collection.class); 

									    System.out.println(clazzProxy); 

									    System.out.println("------constructor method list ------"); 

									    Constructor[] constructors = clazzProxy.getConstructors(); 

									    for(Constructor constructor:constructors){ 

									      StringBuilder sb = new StringBuilder(constructor.getName()); 

									      sb.append("("); 

									      Type[] parameterTypes = constructor.getParameterTypes(); 

									      for(Type parameterType:parameterTypes){ 

									        sb.append(parameterType.toString()+","); 

									      } 

									      if(parameterTypes.length>0){ 

									        sb.deleteCharAt(sb.length()-1); 

									      } 

									      sb.append(")"); 

									      System.out.println(sb.toString()); 

									    } 

									    System.out.println("------constructor method list ------\n\n"); 

									    System.out.println("------ method list ------"); 

									    Method[] methods = clazzProxy.getMethods(); 

									    for(Method method:methods){ 

									      StringBuilder sb2 = new StringBuilder(method.getName()); 

									      sb2.append("("); 

									      Type[] parameterTypes = method.getParameterTypes(); 

									      for(Type parameterType:parameterTypes){ 

									        sb2.append(parameterType.toString()+","); 

									      } 

									      if(parameterTypes.length>0){ 

									        sb2.deleteCharAt(sb2.length()-1); 

									      } 

									      sb2.append(")"); 

									      System.out.println(sb2.toString()); 

									    } 

									    System.out.println("------ method list ------"); 

									    Constructor proxyConstructor = clazzProxy.getConstructor(InvocationHandler.class); 

									    class MyInvocationHandler implements InvocationHandler{ 

									      ArrayList target = new ArrayList(); 

									      public Object invoke(Object proxy, Method method, Object[] args) 

									          throws Throwable { 

									        Object obj = method.invoke(target, args); 

									        return obj; 

									      } 

									    } 

									    MyInvocationHandler mih = new MyInvocationHandler(); 

									    Collection collectionProxy = (Collection) proxyConstructor.newInstance(mih); 

									    collectionProxy.add("zhuang"); 

									    collectionProxy.add("alex"); 

									    System.out.println("collectionProxy size:"+collectionProxy.size()); 

									    Collection collectionProxy2 = (Collection)Proxy.newProxyInstance(Collection.class.getClassLoader(),new Class[] {Collection.class},new InvocationHandler(){ 

									      ArrayList target = new ArrayList(); 

									      public Object invoke(Object proxy, Method method, Object[] args) 

									          throws Throwable { 

									        Object obj = method.invoke(target, args); 

									        return obj; 

									      } 

									    }); 

									    collectionProxy2.add("one"); 

									    collectionProxy2.add("two"); 

									    collectionProxy2.add("three"); 

									    System.out.println("collectionProxy2 size:"+collectionProxy2.size()); 

									  }

运行结果：

									class $Proxy0

									------constructor method list ------

									$Proxy0(interface Java.lang.reflect.InvocationHandler)

									------constructor method list ------

									------ method list ------

									add(class java.lang.Object)

									hashCode()

									equals(class java.lang.Object)

									clear()

									toString()

									contains(class java.lang.Object)

									isEmpty()

									addAll(interface java.util.Collection)

									iterator()

									size()

									toArray(class [Ljava.lang.Object;)

									toArray()

									remove(class java.lang.Object)

									containsAll(interface java.util.Collection)

									removeAll(interface java.util.Collection)

									retainAll(interface java.util.Collection)

									isProxyClass(class java.lang.Class)

									getProxyClass(class java.lang.ClassLoader,class [Ljava.lang.Class;)

									newProxyInstance(class java.lang.ClassLoader,class [Ljava.lang.Class;,interface java.lang.reflect.InvocationHandler)

									getInvocationHandler(class java.lang.Object)

									wait()

									wait(long,int)

									wait(long)

									getClass()

									notify()

									notifyAll()

									------ method list ------

									collectionProxy size:2

									collectionProxy2 size:3