java class知识点_classtoy-优快云博客

本文链接：https://blog.youkuaiyun.com/fxkcsdn/article/details/75670323

本文通过一个Java示例程序展示了如何使用反射获取类的信息，包括类名、是否为接口以及实现的接口等详细信息，并演示了如何利用反射创建对象。

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public interface HasBatteries {

}

public interface Shoots {
}

public interface Waterproof {
}

public class Toy {
Toy(){};//默认构造器,如果不带默认构造器，则不能使用newInstance();创建对象。
Toy(int i){};
}

public class FancyToy extends Toy implements HasBatteries,Waterproof,Shoots{

FancyToy(){
super(1);
}
}

public class ToyTest {
static void printInfo(Class cc){
System.out.println("class name:"+cc.getName()+"is interface? ["+cc.isInterface()+"]");
System.out.println("simple name:"+cc.getSimpleName()+"canonical name "+cc.getCanonicalName()+"");
}

public static void main(String[] args) {
// TODO Auto-generated method stub
Class c=null;
try{
c=Class.forName("com.tkij.chapter14.Class.FancyToy");

}catch(ClassNotFoundException e){
System.out.println("cannot found fancytoy");
System.exit(1);
}
printInfo(c);
for(Class face:c.getInterfaces()){
printInfo(face);
}
Class up=c.getSuperclass();
Object obj=null;
try{
obj=up.newInstance();//使用newInstance()创建的类，必须带有默认的构造器，否则会报InstantiationException异常！
}catch(InstantiationException e){
System.out.println("canot instantiate");
}catch(IllegalAccessException e){
System.out.println("cannot access");
System.exit(1);
}
printInfo(obj.getClass());
}

}/*output
class name:com.tkij.chapter14.Class.FancyToyis interface? [false]
simple name:FancyToycanonical name com.tkij.chapter14.Class.FancyToy
class name:com.tkij.chapter14.Class.HasBatteriesis interface? [true]
simple name:HasBatteriescanonical name com.tkij.chapter14.Class.HasBatteries
class name:com.tkij.chapter14.Class.Waterproofis interface? [true]
simple name:Waterproofcanonical name com.tkij.chapter14.Class.Waterproof
class name:com.tkij.chapter14.Class.Shootsis interface? [true]
simple name:Shootscanonical name com.tkij.chapter14.Class.Shoots
class name:com.tkij.chapter14.Class.Toyis interface? [false]
simple name:Toycanonical name com.tkij.chapter14.Class.Toy
*/