java課件3代理模式類加載器與自定義

4：JDK1.5--1.8--XML--XML類Class 2PropertyDescriptor什么叫3：BeanUtls--對(duì)于JavaBean來說，使用反射操作一個(gè)Studstud=new//通過反射來調(diào)用Methodmethod=Stud.class.getMethod("setName",String.class);method.invoke(stud,"Jerry");Studstud=newPropertyDescriptorpd=newPropertyDescriptor("name",Stud.class);Methodmethod=pd.getWriteMethod();method.invoke(stud,"使用BeanUtils（BeanUtils不是Jdk的一部分，必須要獨(dú)立的去它是apache）

packagesintheJDKJavadocs).However,thesecanbequitecomplextounderstandandutilize.TheBeanUtilscomponentprovideseasy-to-usewrappersaroundthesecapabilities.將完成以后的Jar包，放到項(xiàng)目中buildBeanUtils中的類：兩個(gè)類BeanUtils用于設(shè)置JavaBean的屬性，JavaBean的屬性ConvertUtils上面的異常，ClassNotFoundBeanUtils運(yùn)行要依賴于一個(gè)日志所以，必須要添加日Studstud=newStud();BeanUtils.setProperty(stud,"name","");BeanUtilsStringStudstud=newStud();BeanUtils.setProperty(stud,"age","199");BeanUtils.setProperty(stud,"married","true");BeanUtils.setProperty(stud,"name",newString[]{"Jack","Mary"});BeanUtils.setProperty(stud,"age","199");BeanUtils.setProperty(stud,"married","true");4mapcopypublicvoidtest4()throwsException{Studstud=newStud();Map<StringObjectmapnewHashMap<>();map.put("name","同學(xué)");map.put("age",map.put(" //將map中的所有值，copy到studBeanUtils.BeanUtils.populate(stud,}5：Stringnm=BeanUtils.getProperty(stud,"name");System.err.println("nmis:"+nm);publicDemo04()//只要是在執(zhí)行設(shè)置屬性之前，過類型轉(zhuǎn)換，就可以ConvertUtils.register(newConverter(){public<T>Tconvert(Class<T>dateClass,Objectval)將valSimpleDateFormatsdf=newSimpleDateFormat("yyyy-MM-dd");Datedd=null;trydd=sdf.parse(""+}catch(ParseExceptione){}return(T)}},}在Javapublicvoidtest1()1:獲取StudClassLoaderloader1=Stud.class.getClassLoader();System.err.println(loader1);//sun.misc.Launcher$AppClassLoader@1f96302ClassLoaderloader2=.class.getClassLoader();System.err.println(loader2.getParent().getParent());//nullClassLoaderloader3=String.class.getClassLoader();}packagecn.publicclassDog{publicStringtoString()return"Thisis}}上面的類由AppClassLoader如果希望這個(gè)類由Ext加載器加載，則應(yīng)該打包放到ext擴(kuò) 下自定義類加載器，就是類的二進(jìn)制文件的過程packageimportimportimport*自定義類加載器，就是類的字節(jié)碼的過程publicclassMyClassLoaderextendsClassLoader{publicClass<?>findClass(Stringname)throwsClassNotFoundException{Classcls=null;Filefile=newFile(" InputStreamin=newFileInputStream(file);byte[]bs=newbyte[in.available()];intlen=in.read(bs);cls=defineClass("cn..Dog",bs,0,}catch(Exceptionthrownew}return}}publicvoidtest2()throwsExceptionClasscls=newMyClassLoader().findClass(null);Objectobj=cls.newInstance();}-packageimportimportimport*自定義類加載器，就是類的字節(jié)碼的過程publicclassMyClassLoaderextendsClassLoaderpublicClass<?>findClass(Stringname)throwsClassNotFoundException{Classcls=null;StringfileName=name.rece(".","/");fileName=fileName+".class";InputStreamin=byte[]bs=newbyte[in.available()];intlen=in.read(bs);cls=defineClass(name,bs,0,}catch(Exceptionthrownew}return}} 下的文publicvoidtest3()throwsException{Stringpath= }2: 下的文publicvoidtest4()throwsException{Stringpath= /bin/aa.txtclasspath}5：JDKEnhanced（增強(qiáng)）forLoop（循環(huán)String[]names=int[]ages=for(inti=0;i<names.length;i++){System.err.println(names[i]+"ageis:"+ages[i]);}intanewInteger(30);//Integeraa45;//StaticimportstaticpublicclassDemo01{publicvoidtest1()inta=abs(-TypesafeEnums枚舉Enum定義類publicstaticfinal靜態(tài)常量packagepublicenumGender//1:兩個(gè)變FEMALE,}Genderg1=Gender.FEMALE;Genderg2=使用@interfacepackagepublic@interfaceMyTest}publicclassDemo01{publicDemo01()}publicvoidtest1()public@interfaceMyTest}3：通過反射來注解-重如果通過反射來，必須要注解在運(yùn)行時(shí)存在編譯器將把注釋記錄在類文件中，但在運(yùn)行時(shí)VM。@Retention(Retention.RUNTIME)public@interfaceMyTest{}自己定義一個(gè)主類里面有main方法，一個(gè)注解在主類判斷是否有這個(gè)注解packageimportjava.lang.annotation.ElementType;importjava.lang.annotation.Retention;importjava.lang.annotation.Retention;importjava.lang.annotation.Target;public@interfaceMyRunTest{}packageimportimportpublicclassMyUnitpublicstaticvoidmain(Stringargs)throwsExceptionScannersc=newScanner(System.in);StringclassName=Classcls=Class.forName(className);Objectobj=cls.newInstance();Method[]ms=for(Method}}}}--packageimportorg.junit.After;importorg.junit.Before;importorg.junit.Test;publicclassDemo06{publicvoid}publicvoid}publicvoidtest11(){}publicvoidtest22(){ }}7：1.7BinaryLilsinta=0b1111;UnderscoresinNumericLiinta=inta2=9_3_89_4384;Stringsinswitch在switch里面使用Stringname=switch(name)case}Thetry-with-resourcesStatement//不用調(diào)用in.closetry(InputStreamin=new}//不用調(diào)用in.closetry(InputStreamin=new}catch(NullPointerException|IOException}1.8ladmapublicvoidtest11()throwsException{List<String>list=newArrayList<>();list.forEach(newConsumer<String>(){publicvoidaccept(Stringt){} 以下是使用ladmalist.forEach((Stringt)->{}使用ladmabtn.setOnAction((ActionEventevent)->newAddStud(newAddStud.ICallback(){publicvoidback(Studstud)}publicvoidlongs=Syst