java取得实例对象的几种方法

java获得实例对象的几种方法

// 1.new?
Dog d1 = new Dog();?
d1.say();?
// 2.Class.forName?
Dog d2 = (Dog) Class.forName("com.test.Dog").newInstance();?
d2.say();?
// 3.ClassLoader?
ClassLoader c = ClassLoader.getSystemClassLoader();?
Class classT = c.loadClass("com.test.Dog");?
Dog d = (Dog) classT.newInstance();?
d.say();?
// 4.Constructor

Constructor constructor1 = String.class.getConstructor(StringBuffer.class);
String str2 = (String)constructor1.newInstance(/*"abc"*/new StringBuffer("abc"));
System.out.println(str2.charAt(2));