实例讲解Java基础之反射
今天小编就为大家分享一篇关于实例讲解Java基础之反射，小编觉得内容挺不错的，现在分享给大家，具有很好的参考价值，需要的朋友一起跟随小编来看看吧前期准备
编写一个真实类phone,实现list接口
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;
}
@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;
}
}
1.反射之4种new对象
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
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
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
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
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
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，谢谢大家对CodeAE代码之家的支持。如果你想了解更多相关内容请查看下面相关链接
原文链接：https://blog.csdn.net/qq_34191426/article/details/88141986
http://www.zzvips.com/article/177428.html
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