在阅读书中示例代码的过程中，发现一个被弃用的方法 newInstance()
替代方法：getDeclatedConstructor().newInstance()
//: typeinfo/toys/ToyTest.java
// Testing class Class.
package com.chapter14.toys;
import static com.chapter14.net.mindview.util.Print.print;
interface HasBatteries {}
interface Waterproof {}
interface Shoots {}
class Toy {
// Comment out the following default constructor
// to see NoSuchMethodError from (*1*)
Toy() {}
Toy(int i) {}
}
class FancyToy extends Toy
implements HasBatteries, Waterproof, Shoots {
FancyToy() { super(1); }
}
public class ToyTest {
static void printInfo(Class cc) {
print("Class name: " + cc.getName() +
" is interface? [" + cc.isInterface() + "]");
print("Simple name: " + cc.getSimpleName());
print("Canonical name : " + cc.getCanonicalName());
}
public static void main(String[] args) {
Class c = null;
try {
c = Class.forName("typeinfo.toys.FancyToy");
} catch(ClassNotFoundException e) {
print("Can't find FancyToy");
System.exit(1);
}
printInfo(c);
for(Class face : c.getInterfaces())
printInfo(face);
Class up = c.getSuperclass();
Object obj = null;
try {
// Requires default constructor:
obj = up.newInstance();
} catch(InstantiationException e) {
print("Cannot instantiate");
System.exit(1);
} catch(IllegalAccessException e) {
print("Cannot access");
System.exit(1);
}
printInfo(obj.getClass());
}
} /* Output:
Class name: typeinfo.toys.FancyToy is interface? [false]
Simple name: FancyToy
Canonical name : typeinfo.toys.FancyToy
Class name: typeinfo.toys.HasBatteries is interface? [true]
Simple name: HasBatteries
Canonical name : typeinfo.toys.HasBatteries
Class name: typeinfo.toys.Waterproof is interface? [true]
Simple name: Waterproof
Canonical name : typeinfo.toys.Waterproof
Class name: typeinfo.toys.Shoots is interface? [true]
Simple name: Shoots
Canonical name : typeinfo.toys.Shoots
Class name: typeinfo.toys.Toy is interface? [false]
Simple name: Toy
Canonical name : typeinfo.toys.Toy
*///:~
直接使用 newInstance() 方法：
IDEA会自动把它给划掉
换成 getDeclatedConstructor().newInstance() 方法：
但是要多加一个异常捕捉，如图中的箭头所指。