前期準備
編寫一個真實類phone,實現list接口
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public class phone implements list { public double price; public string name; public phone() { } public phone(double price, string name) { this.price = price; this.name = name; } public double getprice() { return price; } public void gege(string h){ system.out.println("gege的"+h); } public void setprice(double price) { this.price = price; } public string getname() { return name; } public void setname(string name) { this.name = name; } @override public string tostring() { return "phone{" + "price=" + price + ", name='" + name + '\'' + '}'; } @override public int size() { return 0; } @override public boolean isempty() { return false; } @override public boolean contains(object o) { return false; } @override public iterator iterator() { return null; } @override public object[] toarray() { return new object[0]; } @override public boolean add(object o) { return false; } @override public boolean remove(object o) { return false; } @override public boolean addall(collection c) { return false; } @override public boolean addall(int index, collection c) { return false; } @override public void clear() { } @override public object get(int index) { return null; } @override public object set(int index, object element) { return null; } @override public void add(int index, object element) { } @override public object remove(int index) { return null; } @override public int indexof(object o) { return 0; } @override public int lastindexof(object o) { return 0; } @override public listiterator listiterator() { return null; } @override public listiterator listiterator(int index) { return null; } @override public list sublist(int fromindex, int toindex) { return null; } @override public boolean retainall(collection c) { return false; } @override public boolean removeall(collection c) { return false; } @override public boolean containsall(collection c) { return false; } @override public object[] toarray(object[] a) { return new object[0]; }} |
1.反射之4種new對象
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public class test2 { public static void main(string[] args) throws illegalaccessexception, instantiationexception, classnotfoundexception { //第一種 phone p = new phone(2999,"小米"); system.out.println(p);//phone{price=2999.0, name='小米'} //第二種 需要一個空參構造 class<phone> phoneclass = phone.class; phone phone = phoneclass.newinstance(); phone.setname("華為"); phone.setprice(3499); system.out.println(phone);//phone{price=3499.0, name='華為'} //第三種 class<?> aclass = class.forname("com.demo.bean.phone"); phone p2 = (phone) aclass.newinstance(); p2.setprice(2999); p2.setname("魅族"); system.out.println(p2);//phone{price=2999.0, name='魅族'} //第四種,需要一個配置文件phone.properties string name = resourcebundle.getbundle("phone").getstring("myphone"); class<?> bclass = class.forname(name); phone p3 = (phone) bclass.newinstance(); p3.setprice(3299); p3.setname("錘子"); system.out.println(p3);//phone{price=3299.0, name='錘子'} }} |
配置文件phone.properties
myphone=com.demo.bean.phone
2. 反射之獲取類、父類、實現接口
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public class test3 { public static void main(string[] args) throws classnotfoundexception { string string = resourcebundle.getbundle("phone").getstring("myphone"); class<?> aclass = class.forname(string); //獲取類的完整路徑 system.out.println(aclass.getname());//com.demo.bean.phone //獲取類的簡單名字 system.out.println(aclass.getsimplename());//phone //獲取類的父類 class<?> superclass = aclass.getsuperclass(); system.out.println(superclass.getname());//java.lang.object system.out.println(superclass.getsimplename());//object //獲得類的接口 class<?>[] interfaces = aclass.getinterfaces(); for (class<?> in:interfaces ) { system.out.println(in.getsimplename()); } }} |
3.反射之獲取空參、有參構造
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public class test4 { public static void main(string[] args) throws classnotfoundexception, illegalaccessexception, instantiationexception, nosuchmethodexception { string string = resourcebundle.getbundle("phone").getstring("myphone"); class<?> aclass = class.forname(string); //調用的是無參的構造方法 phone p1 = (phone) aclass.newinstance(); p1.setname("華為"); p1.setprice(2999);//phone{price=2999.0, name='華為'} system.out.println(p1); //獲得無參的構造方法 constructor<?> constructor = aclass.getconstructor(); system.out.println(constructor);//public com.demo.bean.phone() //獲得所有的構造方法 constructor<?>[] constructors = aclass.getconstructors(); for (constructor<?> c:constructors ) { system.out.println(c); } }} |
4.反射之獲取方法
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public class test5 { public static void main(string[] args) throws classnotfoundexception, nosuchmethodexception,instantiationexception,illegalaccessexception,invocationtargetexception{ string string = resourcebundle.getbundle("phone").getstring("myphone"); class<?> aclass = class.forname(string); //包含了父類的方法 method[] methods = aclass.getmethods(); for (method m:methods ) { system.out.println(m); } //本類中的方法，沒有父類的方法 method[] declaredmethods = aclass.getdeclaredmethods(); for (method m:declaredmethods ) { system.out.println(m); } method gege = aclass.getmethod("gege",string.class); //獲取gege方法的權限修飾符 system.out.println(modifier.tostring(gege.getmodifiers())); //獲取gege方法的返回值類型 system.out.println(gege.getreturntype()); //設置gege的參數值 object o = aclass.newinstance(); gege.invoke(o,"aa"); }} |
5.反射之獲取字段
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public class test6 { public static void main(string[] args) throws classnotfoundexception, nosuchfieldexception, illegalaccessexception, instantiationexception { string string = resourcebundle.getbundle("phone").getstring("myphone"); class<?> aclass = class.forname(string); //只能調用public 字段,但是能得到父類的字段 field[] fields = aclass.getfields(); for (field f:fields ) { system.out.println(f.getname()); } //只能調用public 字段，只能得到本類中的字段 field[] declaredfields = aclass.getdeclaredfields(); for (field f:declaredfields ) { system.out.println(f.getname()); } //獲取某一字段的數據類型 field name = aclass.getfield("name"); string simplename = name.gettype().getsimplename(); system.out.println(simplename); name.setaccessible(true); object o = aclass.newinstance(); name.set(o,"華為"); system.out.println(name.get(o)); }} |
總結
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原文鏈接：https://blog.csdn.net/qq_34191426/article/details/88141986
