綱Java中的封裝特性 this關(guān)鍵字static關(guān)鍵字final關(guān)鍵字Object內(nèi)、面向過(guò)程與面向?qū)ο蟮膮^(qū)別（蓋飯、蛋炒飯出現(xiàn)問(wèn)題，將會(huì)影響到所有的系統(tǒng)。如：采用面向過(guò)程生產(chǎn)電腦，那么他不會(huì)分CPU、主、類與對(duì)象的概念 “ ”、“602”“J2SE”和“ “ 、類的定義classextendsclassextendsimplements}publicclasspublicclassStudentint int}、對(duì)象的創(chuàng)建和使用Studentzhangsan=newStudent();System.out.println("id="+zhangsan.id); ="+zhangsan. System.out.println("age="+zhangsan.age);}}classStudentint } 000Studentzhangsan=newStudent();zhangsan.id=1001;=" =true;zhangsan.address="";zhangsan.age=20;System.out.println("id="+zhangsan.id);System.out.println("name="+); ="+zhangsan. System.out.println("age="+zhangsan.age);}}classStudentint }、面向?qū)ο蟮姆庋b性Studentzhangsan=newzhangsan.id=1001;=" =zhangsan.address="zhangsan.age=20; System.out.println("id="+zhangsan.id);System.out.println("name="+); ="+zhangsan. System.out.println("age="+}}classStudentint intpublicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}if(studentAge>=0&&studentAge{age=}}{return}}Studentzhangsan=newStudent();zhangsan.id=1001;=" =true;zhangsan.address=" zhangsan.age=20; System.out.println("id="+zhangsan.id);System.out.println("name="+); ="+zhangsan. System.out.println("age="+zhangsan.age);System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get }}classStudentprivate privateintpublicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}以上采用private ， 、構(gòu)造函數(shù)（構(gòu)造方法，構(gòu)造器 造方法修飾詞列表類名（方法參數(shù)列表）void也不能加入，加入Studentzhangsan=newStudent(); System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+zhangsan.getAge());}}classStudentprivateStringprivate privateStringprivateint }publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}}Studentzhangsan=newStudent(1001," ",true,"",System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+}}classStudentprivate privateStringprivateintpublicStudent(intstudentId,StringstudentName,booleanstudent ,StringstudentAddress,intstudentAge){id=name== age=studentAge;}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicintgetAge()returnreturn}}//Studentzhangsan=newStudent(1001, ",true,",Studentzhangsan=newStudent(); System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+}}classStudentprivateStringprivate privateStringprivateintpublicStudent(intstudentId,StringstudentName,booleanstudent ,StringstudentAddress,intstudentAge){id=name== address=studentAddress;age=studentAge;}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}//Studentzhangsan=newStudent(1001, ",true,",Studentzhangsan=newStudent(); System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+}}classStudentpublicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}privateStringprivate privateStringprivateintpublicStudent(){}publicStudent(intstudentId,StringstudentName,booleanstudent ,StringstudentAddress,intstudentAge){id=name== address=studentAddress;age=studentAge;}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}}publicvoid (boolean =student} { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}、對(duì)象和、 內(nèi)存的主要?jiǎng)?class.classJava虛擬機(jī)管.2、 內(nèi)存的表?xiàng)tudents=堆區(qū)中對(duì)堆{id=0}class{intid;Stringname;;Stringaddress;intage;} Studentzhangsan=newzhangsan.id=1001;=" zhangsan.id=1001;=" =true;zhangsan.address="";zhangsan.age=堆堆}Studentzhangsan=棧1.8.3、當(dāng)不使用new//Studentzhangsan=newStudentzhangsan=null;zhangsan.id=1001;=" =true;zhangsan.address=" zhangsan.age=20;System.out.println("id="+zhangsan.id);System.out.println("name="+); ="+zhangsan. System.out.println("age="+zhangsan.age);}}classStudentint }棧null1.8.4傳堆{inti=10;}{temp=}}棧棧method1（）方法棧幀彈出，接下來(lái)執(zhí)iii10，最后將main方法棧幀彈出，main方法執(zhí)行完畢。結(jié)論：只要是基本類型，傳遞過(guò)去的都是Studentstudent=newStudent();student.id=1001;=" =true;student.address=" student.age=20;System.out.println("id="+student.id);System.out.println("name="+); ="+student. }}{ }}classStudentint }棧棧堆 }賦值給temp成了“對(duì)象”，java的收集器會(huì)在某個(gè)時(shí)刻，將其清除 結(jié)論：除了基本類型外都 傳、this關(guān)鍵字需要注意：this只能用在構(gòu)造函數(shù)和成員方法內(nèi)部( 是不能使用this的，關(guān)于static以后再講 部變量和成員變量重名的時(shí)候可以使用this指定調(diào)Studentzhangsan=newStudent(); System.out.println("id="+zhangsan.getId()); ="+zhangsan.get System.out.println("age="+zhangsan.getAge());}}classStudentprivateStringprivate privateStringprivateintpublicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid )如：setId(int如：setId(intid)id=id,這樣寫Javaid賦 } { }{address=}{return}{age=}{return}}Studentzhangsan=newStudent(); System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+zhangsan.getAge());}}classStudentprivateStringprivate privateStringprivateintpublicvoidsetId(int{this.id=} publicintgetId(){returnid;}{=}{return}publicvoid{} publicvoid{} ) { }{this.address=}{return}{this.age=}{return}}局部變量，了解狹義和廣義上的javabean的概念//Studentzhangsan=newStudent(1001,",true,",//Studentzhangsan=newStudent(1001," Studentzhangsan=newStudent(1002," System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+zhangsan.getAge());}}classStudentprivateStringprivate privateStringprivateintpublicStudent(intid,Stringname)this.id=id;=name; newStudent(id,name,true," }publicStudent(intid,Stringname, ,Stringaddress,int{this.id==name; this.age=age;}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}}{return}}publicstaticvoidmain(String[]args){Studentzhangsan=newStudent(1002,"System.out.println("id="+zhangsan.getId());System.out.println("name="+zhangsan.getName()); ="+zhangsan.get System.out.println("age="+}}classStudent棧堆main方法棧幀zhangsan指向堆privateStringprivate privateStringprivateintpublicStudent(intid,Stringname)this.id=id;=name; //newStudent(id,name,true, ",this(id,name,true, ",}publicStudent(intid,Stringname, ,Stringaddress,int{this.id=id;=name; this.age=age;}publicvoidsetId(int{id=}}publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}、staticpublicstaticvoidmain(String[]args){Studentstudent1=newStudent(1001,"Studentstudent2=newStudent(1002,",true,",true,",",}}classStudentprivateStringprivate privateString1.10.1privateintprivateintpublicStudent(intid,Stringname, ,Stringaddress,int{count++;this.id==name; this.age=age;}publicintgetCount(){return}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = }publicboolean () }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}棧publicstaticvoidmain(String[]args){Studentstudent1=newStudent(1001,Studentstudent2=newStudent(1002,",true,",true,",", 堆}}classStudentprivateStringprivate privateStringprivateintprivatestaticintpublicStudent(intid,Stringname, ,Stringaddress,int{count++;this.id==name; this.age=age;}publicintgetCount(){return}publicvoidsetId(int{id=}publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } {}{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}publicstaticvoidmain(String[]args){Studentstudent1=newStudent(1001,"Studentstudent2=newStudent(1002,",true,",true,",",}}classStudent堆的區(qū)域會(huì)初加從classpath加載StudentStudent類的二進(jìn)制結(jié)有執(zhí)行main方法， privateStringprivate privateStringprivateintstaticintpublicStudent(intid,Stringname, ,Stringaddress,int{count++;this.id==name; this.age=age;}publicintgetCount(){return}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean =student} {}{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}{return}}通過(guò)以上分析，static的變量會(huì)放到方法區(qū)中，static 、靜態(tài)方法中實(shí)例變量、實(shí)例方法或 關(guān)鍵}publicvoid{}} new }publicvoid{}}}publicstaticvoid{}}}//privateintage=100;privatestaticintage=100; }}{privateintage=}}publicclass{privatestaticintage=static }static }static }static }publicstaticvoidmain(String[] java虛擬機(jī)調(diào)用起來(lái)會(huì)更方便，直接拿到類就、單例模式初步 //Singletons1=new//Singletons2=new}}classSingletonprivatestaticSingletoninstance=newStudentstudent=newStudent(); }}publicstaticSingletongetInstance(){returninstance;}publicvoidtest() }}1.12、java中的繼承使用extends[修飾符classextends}System.out.println("id="+student.getId());System.out.println("name="+student.getName()); ="+student.get System.out.println("address="+student.getAddress());System.out.println("age="+student.getAge()); Employeeemp=newEmployee(); System.out.println("id="+emp.getId());System.out.println("name="+emp.getName()); ="+emp.get System.out.println("address="+emp.getAddress());System.out.println("age="+emp.getAge());}}classStudentprivateStringprivate privateStringprivateintprivateintpublicStudent(intid,Stringname, ,Stringaddress,int{this.id=id;=name; this.age=age;}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}{this.classesId=}{return}}classEmployeeprivateStringprivate privateStringprivateintprivateintpublicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicintgetAge()Studentstudent=newStudent(); System.out.println("id="+student.getId());System.out.println("name="+student.getName()); ="+student.get System.out.println("address="+student.getAddress());System.out.println("age="+student.getAge()); ="+StudentEmployee 類出來(lái)，讓Student和Employee繼承它，這return}{this.workYear=}{return}}Employeeemp=newEmployee(); System.out.println("id="+emp.getId());System.out.println("name="+emp.getName()); ="+emp.get System.out.println("address="+emp.getAddress());System.out.println("age="+emp.getAge());}} privateStringprivate privateStringprivateintpublicvoidsetId(int{id=} return}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint {this.classesId=}{return}}classEmployee privateint{this.workYear=}{return}}、方法的覆蓋、對(duì)成員方法覆publicstaticvoidmain(String[]args)Studentstudent=newStudent(); Employeeemp=newEmployee();}} privateStringprivate privateStringprivateintpublicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean )= } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}{return}}classEmployee privateprivateint{this.workYear=}{return}}棧堆棧堆{}{}北 }Studentstudent=newStudent(); Employeeemp=newEmployee(); }} privateStringprivate privateStringprivateintpublicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",classesid="+classesId);}}classEmployee privateint{this.workYear=}{return}}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",workYear="+workYear);}}堆棧堆

{{gett}Student{

}{}{}

京動(dòng)力節(jié)點(diǎn)

}}//Studentstudent=new _student= _student=new _emp=newnew子類的時(shí)候，它不會(huì) }} privateStringprivate privateStringprivateintpublicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}publicstaticvoidmain(String[] {return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+",address="+getAddress()+",age="+getAge()+",classesid="+classesId);}="+()+}classEmployee{privateint{this.workYear=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",workYear="+workYear);}} _emp=new = }privatestaticvoid }} privateStringprivate privateStringprivateintpublicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",classesid="+classesId);}}classEmployee privateint{this.workYear=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",workYear="+workYear);}}}定（前期綁定，override是運(yùn)行期間綁定（后期綁定。棧棧堆{}}Student{}京動(dòng)力節(jié)點(diǎn){P{002,publicstaticvoidmain(String[] _emp=new 1.13.2 }privatestaticvoid }} privateStringprivate privateStringprivateintpublicstaticvoidprintInfo() }publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}}{return}publicstaticvoidprintInfo() }}classEmployee{privateint{this.workYear=}{return}publicstaticvoidprintInfo() }}

{

力節(jié)點(diǎn)

}于某一個(gè)類，的是那個(gè)一個(gè)類就調(diào)用的是哪一個(gè)類的靜態(tài)方法和子類沒(méi)有關(guān)系,不像覆蓋了成員方法，new誰(shuí)調(diào)誰(shuí)，為什么覆蓋成員方法可以構(gòu)成多態(tài)（多種狀態(tài)，主要是運(yùn)行、super需要注意：super只能應(yīng)用在成員方法和構(gòu)造方法中，不能應(yīng)用在靜態(tài)方法中（this是一 student=new}} privateStringprivate privateStringprivateint() }1.14.1、調(diào)用默認(rèn)構(gòu)造方publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}_student=new classclassStudent{privateintpublicStudent() }{this.classesId=}{return}}1.14.2 _emp=new _student=newStudent(1001, ",true, ",20,}} privateStringprivate privateStringprivateint () } (intid,Stringname, ,Stringaddress,int{this.id=id;=name; this.age=age;}publicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}{return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateintpublicStudent(intid,Stringname, ,Stringaddress,intage,intclassesId)this.id=id;=name; this.age=age;this.classesId=id; super(id,name, ,address,age);this.classesId=classesId;}{this.classesId=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+",address="+getAddress()+",age="+getAge()+",classesid="+classesId);}="+()+}classEmployee{privateint{this.workYear=}{return}publicvoidprintInfo()System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",workYear="+workYear);}}1.14.3super調(diào)用父類的方法publicstaticvoidmain(String[] _emp=new }privatestaticvoid) }} privateStringprivateStringprivateintpublicvoidprintInfo()System.out.println("id="+id+",name="+name+", ="+ +",address="+address+",age="+age);}publicvoidsetId(int{id=} publicintgetId(){returnid;}{name=}{return}publicvoid (boolean = } { }{address=}return}publicvoidsetAge(intstudentAge)if(studentAge>=0&&studentAge{age=}}publicint{return}}classStudent privateint{this.classesId=}{return}publicvoidprintInfo()//System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",classesid="+classesId);//采用super調(diào)用父類的方法System.out.println("classesId=classesId);}}classEmployee privateint}{return}publicvoidprintInfo()//System.out.println("id="+getId()+",name="+getName()+", ="+get ()+",address="+getAddress()+",age="+getAge()+",workYear="+workYear);}}、final 、采用final修飾的類不能被繼承}}finalclassA1publicvoidtest1()5.2、采用final}}classA1publicfinalvoidtest1()}}classB1extendsA1publicvoidtest1()}publicvoidtest2()}}classB1extends{publicvoidtest2()}}}}}5.3、采用 修飾的變量(基本類型)不能被修1.15.4、 修飾的變量必須顯示初始privatestaticfinallongCARD_NO={int}}privatestaticfinallongCARD_NO=878778878787878L;publicstaticvoidmain(String[]args){CARD_NO=}}1.15.5、如果修飾的，那么這個(gè)只能指向一個(gè)對(duì)象，也就是說(shuō)這個(gè)不能再次賦值，但被指向的對(duì)象是可以修改的 p1= ==p2=p2= }} }棧堆北點(diǎn)、抽象類看我們以前示例中的、StudentEmployee，從我們使用的角度來(lái)看主要對(duì)StudentEmployee進(jìn)行實(shí)例化，中主要包含了一些公共的屬性和方法，而我們通常在java中采用 必須實(shí)現(xiàn)printInfo方法，StudentprintInfo方法，方法名稱不能修改，必須為publicpublicTest01p=new p1=newEmployee(); }} privateString{=、采 抽象}{return}publicvoidcommonMethod1 }}classEmployee }classStudent{}publicTest02}{return}publicvoidcommonMethod1 }}classEmployee }classStudent{}publicTest02p=newp=newp= }}{privateprivateString{=}{return}publicvoidcommonMethod1 } voidprintInfo();}classEmployee }}classStudent{publicvoidprintInfo(){}}、如果這個(gè)類是抽象的，那么這個(gè)類被子類繼承，抽象方法必須被覆蓋。如果在子類中不覆蓋該抽象方法，那么必須將此方法再次為抽象方法publicpublicTest03p=new}}{privateString{=}{return}publicvoidcommonMethod1 }void}classEmployee{}classStudent publicvoidprintInfo}}、抽象類不能被final修飾publicpublicTest04}} privateStringname;{=}{return}publicvoidcommonMethod1 }void}classEmployee publicpublicTest05}}{privateString{=}{return}1.16.5finalpublicvoid{}}classStudent publicvoidprintInfo}} }public void}classEmployee publicvoidprintInfo}}classStudent{publicvoidprintInfo(){}}1.16.6、抽象類中可以沒(méi)有抽象方法（參見、接口(行為 的，不能}}interfaceStudentManager等同voidaddStudent(intid,StringvoidaddStudent(intid,StringvoidaddStudent(intid,String }改}}StringYES="yes";publicstaticfinalStringNO=//int//錯(cuò)誤，不能采用privateprivatestaticfinalintOFF1;}}}publicvoidaddStudent(intid,String}}}interfaceinter1publicvoidpublicvoid}interfaceinter2publicvoid}interfaceinter3extendsinter1publicvoid}{publicvoid}、如果一個(gè)類實(shí)現(xiàn)了接口，那么接口中所有的方法必須實(shí)現(xiàn)Inter1iter1=newIter1Impl();iter1=newIter1Impl123(); Iter1Impliter1Impl=newIter1Impl();//iter1Impl=new}}classIter1ImplimplementsInter1publicvoid{}publicvoid{}publicvoid{}}publicpublicvoid{}publicvoid{}publicvoid{}}{publicvoidmethod1(){}publicvoid{}void}publicvoid}Inter1inter1=newInterImpl();Inter2inter2=newInterImpl();Inter3inter3=newInterImpl();}}classInterImplimplementsInter1,Inter2,Inter3publicvoidmethod1() }publicvoidmethod2() }publicvoidmethod3() }}interfaceinterfaceInter1publicvoid}interfaceInter2publicvoid}interfaceInter3publicvoid}interfaceInterpublicvoidpublicvoid}、java中接口其實(shí)描述了類需要做的事情，類要遵循接口的定義來(lái)做事，使用接口到底有 解決了JavaOraclepublicvoidadd(intid,String{}publicvoiddel(int{}publicvoidmodify(intid,String{}}publicvoidaddStudent(intid,String{}publicvoiddeleteStudent(int{;}publicvoidudpateStudent(intid,String{} publicpublicclassStudentManagerStudentOracleImplstudentOracleImpl=newStudentOracleImpl();studentOracleImpl.add(1," StudentMysqlImplStudentMysqlImplstudentMysqlImpl=newStudentMysqlImpl();studentMysqlImpl.addStudent(1," studentMysqlImpl.udpateStudent(1,"");}} publicvoidadd(intid,String{}publicvoiddel(int publicvoidadd(intid,String{}publicvoiddel(int{}publicvoidmodify(intid,String{}}publicvoidadd(intid,String{}publicvoiddel(intid)}publicvoidmodify(intid,String{}}IStudentistudent=newStudent4OracleImpl();IStudentistudent=newStudent4MysqlImpl();istudent.add(1,"");istudent.modify(1," //IStudentistudent=new//IStudentistudent=newdoCrud(newStudent4MysqlImpl());} ，publicstaticvoiddoCrud(IStudentistudent){istudent.add(1," istudent.modify(1," }{istudent.add(1,istudent.modify(1,"}}就是多態(tài)的一種表現(xiàn)，此時(shí)成為靜態(tài)多態(tài)。另外就是學(xué)生保存到數(shù)據(jù)的示例，當(dāng)我們OracleMySqlMySql中的方法，這是在運(yùn)行期決定的。多態(tài)的、接口和抽象類的區(qū)別？、類之間的關(guān)系A(chǔ)B ABpublicclassA}}CD}}}}FEjava語(yǔ)言學(xué)班 汽-汽 -輪輪 人- -四四 publicclass學(xué)publicclass學(xué) 部分，在java語(yǔ)言中使用實(shí)例變量體現(xiàn)publicclass汽}publicclass輪} java語(yǔ)言中使publicclassprivate四肢集合四肢publicclass四{privatepublicinterfaceIpublicinterfaceIpublicvoidmethod1()}{publicvoidmethod1()}publicvoidmethod2()}}publicinterfaceIpublicvoidmethod1()}{publicvoidmethod1()}}publicclassTestpublicstaticvoidmain(String[] = }}{}{privateB}publicpublicclassB}、Object Object類是所有Java{inti=100;=.id=.name= 1.23.1、字符串，Object類的toString方法返回一個(gè)字符串，該字符串由類名加標(biāo)記@希碼的無(wú)符號(hào)十六進(jìn)制表示組成，ObjecttoStringgetClass().getName()+'@'+publicclassUser}publicclassUsere