适配器:当复用一个存在的类A或者创建一个复用的类 ,它的
接口不符合你的需求,采用此模式可以不在用子类,而是面向接口的原则进行使用
存在的类
package com.adapterpattern;
public class A {
	public void testA(){
		System.out.println("THIS IS TESTA");
	}
}
接口 
package com.adapterpattern;
public interface Target {
	public void testA();
	public void testB();
}
实现类
package com.adapterpattern;
public class Aadapter implements Target {
	private A a = new A();
	public Aadapter(A a) {
		this.a = a;
	}
	@Override
	public void testA() {
		this.a.testA();
	}
	@Override
	public void testB() {
		System.out.println("THIS IS TESTB");
	}
}
测试类
package com.adapterpattern;
public class Test {
	public static void main(String[] args) {
		Target a = new Aadapter(new A());
		a.testA();
		a.testB();
		
	}
}
输出
THIS IS TESTA
THIS IS TESTB