第14章java反射机制新浪微博尚

允许程序在执行期借助于ReflectionAPI取得任何类的内14-214-2理解Class类并ClasspublicfinalClassClass器、某个类到底实现了哪些接口。对于每个类而言，JRE都为staticClassforName(StringObjectClassClass[]ClassMethodgetMethod(Stringname,Class…paramTypes)Stringstr= Classclazz=Objectobj=Fieldfield=Objectobj2= 实例：Classclazz实例：Classclazz= 实例：Classclazz=Class.forName(“java.lang.String”);Classclazz4=cl.loadClass(“类的全类名”);14-3类的加载下系统类加载器：负责javaclasspath或–Djava.class.path所指的下的类与jarSystemClassloaderExtensionClassloaderBootstapClassloader 类加载器是用来把类(class)装载进内存的。JVM规范定义了BootstapClassloader ClassLoaderclassloader=classloader=classloader=classloaderclassloaderInputStreamin=in=14-414-4 3Stringname=“atguigu.java. Classclazz=null;clazz=p2=( )con.newInstance("Peter",20);14-5publicClass<?>[]publicClass<?SuperT>型）Class。publicConstructor<T>[]publicConstructor<T>[] 取得修饰符publicint取得方法名称publicString取得参数的类型：publicClass<publicMethod[]publicMethod[]publicField[]publicField[]publicintgetModifiers()以整数形式返回此FieldpublicClass<getType()得到FieldpublicStringgetName()返回FieldgetAnnotation(Class<T>获取父类泛型类型：Type类所在的包Package14-614-6之后使用Objectinvoke(ObjectobjObjectargs)进行调用，并向方法

Objectinvoke(Objectobj,Object Object若原方法若为静态方法，此时形参Objectobj可为null3.若原方法形参列表为空，则Object[]args为null publicFieldgetDeclaredField(Stringname)返回此Class对象表示的类或接口的publicvoid 14-7 将对象包装起来,然后用该 代原始对象.任何对原始对象的调用都要通过 staticClass<?> Class(ClassLoaderloader,Class<?>...interfaces)创建一个动态 staticObject Instance(ClassLoaderloader,Class<?>[]interfaces,InvocationHandlerh)直接创建一

publicObjectinvoke(Objectthe ,Methodmethod,Object[]params)throwsThrowable{{Objectretval=method.invoke(targetObj,//Printouttheresultreturn}

catch(Exception}

say(Stringsay(Stringname,int InvocationHandlerh)创建一个Subject接口RealSubjecttarget=newRealSubject();//Createa towraptheoriginalimplementation =newDebug //Getareferencetothe throughtheSubjectinterfaceSubjectsub=(Subject) newClass[]{Subject.class Stringinfo=sub.say(“Peter",24); 与AOP（AspectOrient

与AOP（AspectOrient

与AOP（AspectOrientpublicinterfaceDog{voidinfo();void}}}} 与AOP（AspectOrientpublicpublicclasspublicvoid}publicvoid}} 与AOP（AspectOrient//需要 this.target=target;}//执行动 publicObjectinvoke(Object ,Methodmethod,Object[]args)throwsException{DogUtildu=new 与AOP（AspectOrientpublicclass publicstaticObjectget throwsException{//MyInvokationHandlerhandler=newMyInvokationHandler(); }}publicclasspublicstaticvoidpublicclasspublics