前期准备
编写一个真实类phone,实现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种new对象
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public class test2 { public static void main(string[] args) throws illegalaccessexception, instantiationexception, classnotfoundexception { //第一种 phone p = new phone( 2999 , "小米" ); system.out.println(p); //phone{price=2999.0, name='小米'} //第二种 需要一个空参构造 class <phone> phoneclass = phone. class ; phone phone = phoneclass.newinstance(); phone.setname( "华为" ); phone.setprice( 3499 ); system.out.println(phone); //phone{price=3499.0, name='华为'} //第三种 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'} //第四种,需要一个配置文件phone.properties string name = resourcebundle.getbundle( "phone" ).getstring( "myphone" ); class <?> bclass = class .forname(name); phone p3 = (phone) bclass.newinstance(); p3.setprice( 3299 ); p3.setname( "锤子" ); system.out.println(p3); //phone{price=3299.0, name='锤子'} } } |
配置文件phone.properties
myphone=com.demo.bean.phone
2. 反射之获取类、父类、实现接口
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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); //获取类的完整路径 system.out.println(aclass.getname()); //com.demo.bean.phone //获取类的简单名字 system.out.println(aclass.getsimplename()); //phone //获取类的父类 class <?> superclass = aclass.getsuperclass(); system.out.println(superclass.getname()); //java.lang.object system.out.println(superclass.getsimplename()); //object //获得类的接口 class <?>[] interfaces = aclass.getinterfaces(); for ( class <?> in:interfaces ) { system.out.println(in.getsimplename()); } } } |
3.反射之获取空参、有参构造
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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); //调用的是无参的构造方法 phone p1 = (phone) aclass.newinstance(); p1.setname( "华为" ); p1.setprice( 2999 ); //phone{price=2999.0, name='华为'} system.out.println(p1); //获得无参的构造方法 constructor<?> constructor = aclass.getconstructor(); system.out.println(constructor); //public com.demo.bean.phone() //获得所有的构造方法 constructor<?>[] constructors = aclass.getconstructors(); for (constructor<?> c:constructors ) { system.out.println(c); } } } |
4.反射之获取方法
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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); //包含了父类的方法 method[] methods = aclass.getmethods(); for (method m:methods ) { system.out.println(m); } //本类中的方法，没有父类的方法 method[] declaredmethods = aclass.getdeclaredmethods(); for (method m:declaredmethods ) { system.out.println(m); } method gege = aclass.getmethod( "gege" ,string. class ); //获取gege方法的权限修饰符 system.out.println(modifier.tostring(gege.getmodifiers())); //获取gege方法的返回值类型 system.out.println(gege.getreturntype()); //设置gege的参数值 object o = aclass.newinstance(); gege.invoke(o, "aa" ); } } |
5.反射之获取字段
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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); //只能调用public 字段,但是能得到父类的字段 field[] fields = aclass.getfields(); for (field f:fields ) { system.out.println(f.getname()); } //只能调用public 字段，只能得到本类中的字段 field[] declaredfields = aclass.getdeclaredfields(); for (field f:declaredfields ) { system.out.println(f.getname()); } //获取某一字段的数据类型 field name = aclass.getfield( "name" ); string simplename = name.gettype().getsimplename(); system.out.println(simplename); name.setaccessible( true ); object o = aclass.newinstance(); name.set(o, "华为" ); system.out.println(name.get(o)); } } |
总结
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原文链接：https://blog.csdn.net/qq_34191426/article/details/88141986