This 㶗⹩ᒂ‫ݼ‬ᄨ䆐ȡ
Public void printNum(){ Int number=40喛 System.out.println(this.number);
} ₓᬥគ࢟⮳᭞ჍҺइ䛾喌㔻䲍ᅯ䘗इ䛾喌ࢢ჉͸౗ㆪ͜㔻䲍᫨∄͜⮳इ䛾ȡ
This.number 㶗⹩ჍҺइ䛾ȡ 䄰䄲⩗ this.number 䗒ͷ䄰ࢢͩᒂ‫(ݼ‬this)ᄨ䆐⮳ number ᫨∄ȡ
‫ڢ‬㈪䓿テさ喚instanceof a instanceof Animal;(䔈͙ᐾၿ⮳㐂᳋᭞̯͙ጲᅃ㶗䓭ᐾ) D ͩᄨ䆐इ䛾喌Animal ᭞ㆪ़ȡ ̹䲑䄜औ᭞‫ݓ‬჉ D ᭞ॕञД䉣 Animal ᴶキȡັ᳋ञД䉣݈䔃఍ true喌ॕ݈䔃఍ falseȡ
౗̹䲑⮳䷇Ⱍ͜喚 a instanceof Animal 䔃఍ True喌 a instanceof Dog Ύ䔃఍ True喌
䲑ीᄨ䆐᫨∄⮳䛼䒬喈overloading喉঻㺵Ⰵ喈overriding喉ȡ ౗᰸ϊ JAVA Εㅼ͜ᄵ overriding 土ͩ䛼䒬喌overloading 土ͩ䓶䒬ȡ
Overloading ౗̯͙ㆪ͜ञД჉͸้͙ऻ़᫨∄喌ळ͙᫨∄⮳ࣱ᪟㶗̯჉̼ऻȡѵԝ亟䃼 ञ㘬Ⱗऻ喌䔃఍իΎञ㘬Ⱗऻȡ
౗彡Ꮎ⮳㑅䄀䓶彡͜ᵨᢝइ䛾ㆪ಺ᲔឭⰧᏃ⮳᫨∄ȡఏₓΎ᰸ϩ䃓ͩ overloading ᭞㑅 䄀ᬥ⮳้ᔰ喌ДऽᝀЛ䔇щ႕‫ݟ‬䓿㵻ᬥ้ᔰȡ
ㆪ᫨∄͜⮳̯ㆪ➨₹᫨∄喚Ჳ䕏᫨∄ȡ Ჳ䕏᫨∄᭞ᒂ⩗ㆪ⩎᜿ᄨ䆐ᬥ喌㈪㐎౗⩎᜿ᄨ䆐⮳䓶彡͜‫⮳⩗ݘ‬᫨∄ȡ ∗ᘾ喚Ჳ䕏᫨∄౗⩎᜿ᄨ䆐⮳ᬥՈщ㷚䄲⩗喌ѵᎥ̼᭞Ჳ䕏᫨∄⩎᜿εᄨ䆐ȡ Ჳ䕏᫨∄⇐᰸䔃఍իȡᵫᐾͩ喚public ᫨∄़ȡ Ჳ䕏᫨∄⮳᫨∄़̽ㆪ़Ⱗऻȡ Ჳ䕏᫨∄᭞౗ᄨ䆐⩎᜿⮳䓶彡͜㜙ߗ䄲⩗喌̼ञ㘬‫⩗ݘ‬ᠶГ࣪䄲⩗ȡ ౗̯͙ᄨ䆐⮳⩎᜿গᱎ͜Ჳ䕏᫨∄ङ⩗̯⁐喌̯ᬕ䔈͙ᄨ䆐⩎᜿喌䗒ͷ䔈͙Ჳ䕏᫨∄๠᩷ȡ
᫨∄⮳㺵Ⰵ喈overriding喉 ᫨∄⮳䛼䒬Ꭵ̼̯჉᭞౗̯͙ㆪ͜喚ၿㆪञДϽ❥ㆪ㐖ឮ̯͙᫨∄喌ΎञД჉͸̯͙ऻ़ᐱ ࣱ⮳᫨∄喌Ύ土ͩ overloadingȡ ᒂၿㆪϽ❥ㆪ㐖ឮ̯͙ᬏࣱ᫨∄喌㔻ࣷ჉͸ε̯͙ऻᵦ⮳ᬏࣱ᫨∄喌݈ၿㆪ᫟‫⮳ۈ‬᫨∄㺵Ⰵ ❥ㆪ⮳᫨∄喌土ͩ㺵Ⰵȡ喈∗ᘾ䔃఍իㆪ಺Ύᓴ䶪Ⱗऻ喌ॕ݈㑅䄀‫ܩ‬䩈ȡ喉 ັ᳋᫨∄̼ऻ喌݈᜿䛼䒬ȡ
㺰‫ڪ‬᜿㞞ຬ⮳㑅彡Ώᘞ喚ᅠ᭞㺰ߏ̹吇䃓⮳❥ㆪᬏࣱ⮳Ჳ䕏᫨∄ȡ ᕌ㔲喚ञ᭞ັ᳋ᝀЛ⇐᰸჉͸ᬏࣱ⮳Ჳ䕏᫨∄喌㔻౗彡Ꮎ͜Ჳ䕏ε᰸ࣱ⮳Ჳ䕏᫨∄喌䗒ͷັ ᳋᫨∄͜⇐᰸ࣱ᪟喌䗒ͷ㈪㐎䔇щ䄲⩗᰸ࣱ⮳Ჳ䕏᫨∄ͷ喟Ꮓ䄔̼щȡ
้ᔰ喚้ᔰᠶ⮳᭞㑅䄀ᬥㆪ಺इࡅ喌㔻䓿㵻ᬥㆪ಺̼इȡ ้ᔰ͓ܵ⻼喚 Ř 㑅䄀ᬥ้ᔰ喚㑅䄀ᬥߗᔰ䛼䒬喛 ř 䓿㵻ᬥ้ᔰ喚ᠶ̯͙ᄨ䆐ञД‫ڦ‬᰸้͙ㆪ಺ȡ
ͩϯͷ㺰Ү⩗䲑ीᄨ䆐喚 仅‫ٷ‬喌䲑ीᄨ䆐さषϩㆪⰺᒴκ➘⮳̯㝛㻳ᒺȡ ᄨ䆐⮳᫨∄⮳Ⴭ⣟㏵㞱᭞ᅾ㩬⮳喌ङ᰸ᄨ䆐᫨∄⮳Ⴭ⣟㔴ε㼒㏵㞱ȡ ᫨∄⮳჉͸䲍፧䛼㺰ȡ᫨∄᰸ࣱ᪟喌Ύञ㘬᰸䔃఍իȡ
∗ᘾࡩܵ喚ᄨ䆐喈ᱛ䏚喉Ƞᄨ䆐⮳Ⴭ⣟㔴Ƞᄨ䆐⮳䄲⩗㔴ȡ ܵᲿᄨ䆐ͪ㺰Ͻ᫨∄ᐯ໺ȡ ᝀЛ䕉䓶ㆪᲔⰺᒴᄨ䆐喌ㆪ᭞ᄨ䆐⮳៬䆐ȡ
ᄰ㷴喚Үᄨ䆐⮳ᆍᕖᅬञ㘬⻰᰸喌ᄨ䆐⮳᫨∄ᅬञ㘬⮳‫ڛ‬ᐯȡ⩗ private 㶗⹩ₓ᜿ইᆍᕖͩ
䖒‫ ݙ‬java ᄺдヨ䆄
3
䄔ㆪ⮳⻰᰸ᆍᕖȡ
Public 㶗⹩䄔ᆍᕖ喈᫨∄喉‫ڛ‬ᐯ喛 Private 㶗⹩䄔ᆍᕖ喈᫨∄喉ͩङ᰸ᱛㆪ‫ڴ‬䘗ञД䃮䬝喈ㆪ‫ڴ‬䘗ञ㻰喉ȡ 喈ᘢ⩗ private 䔇㺰⩗ set ঻ get ᫨∄ӊ‫ڥ‬Ѕ᫨∄䄲⩗喌䔈ᵦञДԌ䃰ᄨᆍᕖ⮳䃮䬝᫨ᐾ㐎 ̯喌Ꭵ̓Ӯν㐣៓䃮䬝ᱲ䭿Дࣹᆍᕖ᪟ᢝष∄ᕖ喉 ັ᳋⇐᰸➨₹ᗴۤ喌ᆍᕖ̯჉⻰᰸喌᫨∄䄔‫ڛ‬ᐯ⮳‫ڛ‬ᐯȡ ັ᳋̼ᠶᬽ䄰䄲⩗᫨∄喌݈吇䃓ͩ thisȡ ࡩܵჍҺइ䛾঻ᅯ䘗इ䛾ᬥ̯჉㺰‫ ۈ‬thisȡ
ᄨν᫨∄⮳ԝ亟䃼喌ၿㆪ᫨∄㺰℃❥ㆪ⮳᫨∄㠲ణᰣߏ⮳წ∊ȡ ❥ㆪͩ public喌䗒ͷၿㆪͩ private ݈‫ܩ‬⣟䩈䄞ȡ ͺᝯДᲳ䕏᫨∄‫ٷ‬䓿㵻❥ㆪ‫ڼ‬䓿㵻ၿㆪ᭞ఏͩᲳ䕏᫨∄᭞ᬏ∄㺵Ⰵ⮳ȡ Д̺㠲ణӌ⁐⩠͔‫ݟ‬წ喚 private 喚ᱛㆪ䃮䬝喛 default 喚㶗⹩吇䃓喌̼ϴᱛㆪ䃮䬝喌㔻̓᭞ऻ࠴ञ㻰ȡ Protected喚ऻ࠴ञ㻰̼ऻ࠴⮳ၿㆪञ㻰 Public 喚㶗⹩ᝯ᰸⮳౟᫨౶ञ㻰ȡ
℃䒲䲑ी䓶彡⮳ᕌᘢ঻䲑ीᄨ䆐⮳ᕌᘢ喚 䲑ी䓶彡⮳ᕌᘢ喚⩠䓶彡Ƞₔ俓Ƞ‫ܬ‬᪟㏳᜿喌Д䓶彡ͩᵧᓲ喛 䲑ीᄨ䆐⮳ᕌᘢ喚Дᄨ䆐ͩ͜ᓲ喌‫ٷ‬ᐯऀㆪ喌ᓆ‫ݟ‬ᄨ䆐喌䕉䓶ᄨ䆐ͺ䬣Ⱗρ䕉ԐჍ⣟ߎ㘬ȡ 䲑ी䓶彡᭞‫ٷ‬᰸テ∄喌ऽ᰸᪟ᢝ㐂Ჳȡ 䲑ीᄨ䆐᭞‫ٷ‬᰸᪟ᢝ㐂Ჳ喌♥ऽ‫ڼ‬᰸テ∄ȡ
౗⩗䲑ीᄨ䆐ᕌᘢᐯऀ⮳䓶彡͜喌ञД฼⩗ᄨ䆐ᅠ䔊㵻฼⩗喌ັᬏ∄䔊㵻฼⩗݈ᐯऀ᫟⮳ᄨ 䆐ȡ ᐯऀ䓶彡᭞⩗ᄨ͙クࢄ⮳ᄨ䆐⮳้͙クࢄ⮳᫨∄喌ᲔჍ⣟฼ᱱ⮳ߎ㘬ȡ Ͻ䄜∄̹Ეⰺ喌̯͙ㆪ᭞̯͙᫟⮳᪟ᢝㆪ಺ȡ ౗䲑ीᄨ䆐㑅彡͜喌䮓εクࢄ᪟ᢝㆪ಺喌ᅠ᭞ᄨ䆐ㆪ಺ȡ ჉͸ㆪ⮳ᵫᐾ喚 class Student{
Вⴰ }
䖒‫ ݙ‬java ᄺдヨ䆄
1
∗ᘾㆪ़͜ࢄ䃼⮳仅ႆ⃼๖‫ۈ‬ȡ ჍҺइ䛾喚჉͸౗ㆪ͜ѵ౗Ъ҄᫨∄ͺๅȡ喈New ‫ܩ‬Ე⮳౶᰸‫݌‬ի喉 ᅯ䘗इ䛾喚჉͸౗᫨∄ͺ͜⮳इ䛾ȡ ᅯ䘗इ䛾㺰‫ٷ‬䉺ի喌‫ڼ‬䔊㵻䓿テ喌㔻ჍҺइ䛾౶ጡ㏾䉺‫݌‬իȡ䔈᭞ᅯ䘗इ䛾঻ჍҺइ䛾⮳̯ ๖ࡩ‫ݚ‬ȡ ჍҺइ䛾⮳ᄨ䆐䉺իͩ nullȡ ᅯ䘗इ䛾ٰ̼䃧㠲ణ‫ڴ‬჉͸͓͙ऻ़इ䛾ȡჍҺइ䛾⮳ҋ⩗എ౗ᱛㆪ͜Ⴛ‫ڗ‬᰸᩷喌ᒂ㷚‫ڥ‬Ѕ ⮳ㆪ䄲⩗⮳ᬥՈΎञ㘬᰸᩷ȡ ჍҺइ䛾঻ᅯ䘗इ䛾ٰ䃧ব़ۡ革ȡ
Overloading ᫨∄᭞Ͻѽी倇䒛ȡ Byte—short—float—int—long—doubleȡ
౗Ჳ䕏᫨∄͜喌this 㶗⹩ᱛㆪ⮳‫ڥ‬ЅᲳ䕏᫨∄喚 student(){}; student(string n){
this();//㶗⹩䄲⩗ student() } ັ᳋䄲⩗ student(int a)݈ͩ this(int a)ȡ ➨‫∗ݚ‬ᘾ喚⩗ this 䄲⩗‫ڥ‬ЅᲳ䕏᫨∄ᬥ喌this ᓴ䶪ͩせ̯Ა䄜औ喌♥ऽ᝼᭞‫ڥ‬Ѕ䄜औȡ
ᒂᲳ䕏̯͙ᄨ䆐⮳ᬥՈ喌㈪㐎‫ٷ‬Ჳ䕏❥ㆪᄨ䆐喌‫ڼ‬Ჳ䕏ၿㆪᄨ䆐ȡ Ჳ䕏̯͙ᄨ䆐⮳䶩Ꮎ喚喈∗ᘾ喚Ჳ䕏❥ㆪᄨ䆐⮳ᬥՈΎ᭞䔈܏ₔ喉 Ř 䕁ᒁ౟Ჳ䕏❥ㆪᄨ䆐喛 ř 䶩Ꮎ౟䄲⩗ᱛㆪ᜿ইᆍᕖ䉺‫݌‬ի䄜औ喛 Ś ᱛㆪ⮳Ჳ䕏᫨∄ȡ
Super()㶗⹩䄲⩗❥ㆪ⮳Ჳ䕏᫨∄ȡ
䖒‫ ݙ‬java ᄺдヨ䆄
4
Super()Ύ঻ this ̯ᵦᓴ䶪ᩭ౗せ̯㵻ȡ This()⩗ν䄲⩗ᱛㆪ⮳Ჳ䕏᫨∄ȡ ັ᳋⇐᰸჉͸Ჳ䕏᫨∄喌䗒ͷᅠщ䄲⩗❥ㆪ⮳ᬏࣱᲳ䕏᫨∄喌ࢢ super()ȡ
ͩϯͷщႇ౗ overloading ឯᱞ঑喟ҋͩᏃᄨ᫨∄⮳㏵㞱ȡ ‫⩗ݘ‬ㆪ಺⮳ጝᐱᲔᒠৼᄨ᫨∄⮳䄲⩗ȡ ल喈喉ञДܵͩल㖸喌ल㤋喌ल㢞喌౗̯͙ㆪ͜ञД჉͸้͙ल᫨∄ȡ
Ჳ䕏᫨∄ΎञДჍ⣟ overloadingȡҺ喚 public void teach(){}; public void teach(int a){}; public void teach(String a){}̸ͩ⻼̼ऻ⮳᫨∄ȡ
ञДᲳ䕏้͙Ჳ䕏᫨∄喌ѵ้͙Ჳ䕏᫨∄⮳ࣱ᪟㶗̯჉̼ऻ喌ࣱ᪟䶩Ꮎ̼ऻࢢᆍν̼ऻ⮳Ჳ 䕏᫨∄喚 public student(string name,int a){ } public student(int a,string name){ } ͓͙̼ͩऻ⮳Ჳ䕏᫨∄ȡ
䖒‫ ݙ‬java ᄺдヨ䆄
2
ັ᳋ᝀЛ᱙㐈㈪㐎᣿ӊ̯͙Ჳ䕏᫨∄喌䗒ͷ㈪㐎щ㜙ߗ᣿ӊ̯͙ͩ阜⮳Ჳ䕏᫨∄ȡ ㏲Ώ喚‫͙̯ۈ‬ㆪ喌჉͸̯͙ᄨ䆐喌჉͸͓͙Ჳ䕏᫨∄喚̯͙᰸ࣱ喌̯͙ᬏࣱȡ 喈㑅‫彡͙̯ۈ‬Ꮎ侻䃰ᄨ䆐⮳я䕁⮳իͩ౟౯喉 ∗ᘾ̺䲑䔈⻼ᒑᐾ喚 static void changename(student stu){stu.setName “LUCY”} ∗ᘾ⩎᜿᫟⮳ᄨ䆐̽ᬖᄨ䆐ᠶीᬏ‫ڢ‬喌⩎᜿᫟ᄨ䆐⩎ব⊷ϐ̽ᬖᄨ䆐ᬏ‫ڢ‬ȡ
11.29
㐖ឮ喚 ❥ㆪ喈SuperClass喉঻ၿㆪ喈SonClass喉ȡ ❥ㆪ⮳䲍⻰᰸ࡅᆍᕖ঻᫨∄ञД吇䃓㐖ឮ‫ݟ‬ၿㆪȡ Class Son extends Father{ } 㔻ັ᳋❥ㆪ͜⮳⻰᰸᫨∄㷚ၿㆪ䄲⩗⮳䄌喌݈㑅䄀។䩈ȡ
❥ㆪ⮳Ჳ䕏᫨∄ၿㆪ̼ञД㐖ឮ喌ᰣ̼ႇ౗㺵Ⰵ⮳䬝䷇ȡ喈䲍Ჳ䕏᫨∄ञД喉 ັ᳋ၿㆪ䃮䬝❥ㆪ⮳Ჳ䕏᫨∄喌݈౗㑅䄀⮳ᬥՈ᣿⹩䃮䬝̼‫ݟ‬䄔᫨∄ȡ JAVA ٰ̼͜䃧้㐖ឮ喌̯͙ㆪ᰸̓ङ᰸̯͙❥ㆪ喈ࢄ㐖ឮ喉ȡ JAVA ⮳᪟ᢝ㐂Ჳͩᵀ಺㐂Ჳ喌㔻䲍㒀⟥ȡ喈JAVA 䕉䓶ᣔऒ঻‫ڴ‬䘗ㆪჍ⣟้㐖ឮ喉
ᄨ䆐᭞ბ㻱⮳喌ϩᄨᄨ䆐⮳䃓䃵᭞ͪ㻱⮳ȡ Һ喚 Animal a=new Dog()喛ᴔⰺᵫᐾ़土喛 Dog d=(Dog)aȡฟᬽ❥ㆪᲔᑄ⩗ၿㆪȡ 喈ᕌ㔲̹䲑⮳ᵫᐾ喉
䓿㵻ᬥ้ᔰ⮳̸݈࣎喚喈Ꮓ⩗ᬥͩ㺵Ⰵ喉 Ƞ ᄨ䆐̼इ喛喈ᩨइ⮳᭞ͪ㻱䃓䃵喉 Ƞ ᄨνᄨ䆐⮳䄲⩗ङ㘬䭿ν㑅䄀ᬥㆪ಺⮳᫨∄喌ັ䄲⩗䓿㵻ᬥㆪ಺᫨∄។䩈ȡ ౗̹䲑⮳Һၿ͜喚Animal a=new Dog()喛ᄨ䆐 D ⮳㑅䄀ᬥㆪ಺ͩ Animal喌䓿㵻ᬥㆪ಺ͩ dogȡ ∗ᘾ喚㑅䄀ᬥㆪ಺̯჉㺰ͩ䓿㵻ᬥㆪ಺⮳❥ㆪ喈ᝅ㔴ऻㆪ಺喉ȡ ᄨν䄜औ喚Dog d=(Dog)aȡᄵ G ᑩ‫ݥ‬ฟᬽͩ D ㆪ಺喌ₓᬥ G ͩ Dog()喌ₓᬥ G ᅠञД䄲⩗䓿 㵻ᬥㆪ಺ȡ∗ᘾ喚D ঻ G ᠶीऻ̯ᄨ䆐ȡ Ƞ ౗彡Ꮎ⮳䓿㵻ᬥ喌ߗᔰㆪ಺‫ݓ‬჉ȡ䓿㵻ᬥ䄲⩗䓿㵻ᬥㆪ಺喌ࢢႲ䄲⩗㺵Ⰵऽ⮳᫨∄ȡ
JAVA ⮳䲑ीᄨ䆐㑅彡--------䄭റぃ䃟
䲑ीᄨ䆐ͪ㺰䦷ᄨ䲑ी䓶彡ȡ 䲑ी䓶彡⮳ഩᱛࢄ‫ٲ‬᭞‫ܬ‬᪟ȡ
ϯͷ᭞ᄨ䆐喚EVERYTHING IS OBJECT喈̶➘⮵ᄨ䆐喉
ᝯ᰸⮳κ➘䘬᰸͓͙᫨䲑喚 ᰸ϯͷ喈ᆍᕖ喉喚⩗Ე᣾䔟ᄨ䆐ȡ 㘬๎։ϯͷ喈᫨∄喉喚ॹ䃸ๅ⩻ᄨ䆐᰸䗒ϊߎ㘬ȡ ऽ㔴Д‫ݼ‬㔴ͩഩⵯȡ ๖⮳ᄨ䆐⮳ᆍᕖΎञД᭞̯͙ᄨ䆐ȡ
‫⁐ڥ‬喌䛶⩗䲑ीᄨ䆐᫨∄ञДҮ㈪㐎ळ䘗ܵळध‫ڥ‬㕻Ƞळᅬᝯ㘬ȡ ᄨ䆐ͺ䬣⮳㕕षᕖ̯჉㺰ѽ喈℃ັ̼ऻ⶛Ⰷ঻̼ऻͪᲮͺ䬣⮳‫ڢ‬㈪喉ȡ䔈ᵦ᝼㘬Ү⃾͙ᄨ䆐 ᱛ䏚։᜿ᰯຬ⮳ȡ