定义一个类

package com.zx;
public class NotebookComputer {private int num;	private CPU cpu;public String fromIntoBit(){	class CPU2{// 局部内部类public String countBit(int num){return Integer.toBinaryString(num);}}return (new CPU2().countBit(num));}/**** 普通内部类*/
private final class CPU{}public NotebookComputer(int num){this.num = num;if(cpu == null)cpu = new CPU();}}

定义测试类

package com.zx;public class TestInnerClass {public static void main(String[] args) {
//		// 创建一个外部类
//		NotebookComputer com = new NotebookComputer();
//		// 声明一个内部类
//		NotebookComputer.CPU cpu;
//		
//		// 通过外部类的实例创建一个内部类对象
//		cpu = com.new CPU();
//		
//		String bitStr = cpu.countBit(11);
//		System.out.println(bitStr);NotebookComputer com = new NotebookComputer(9);System.out.println(com.fromIntoBit());//		System.out.println(com.fromIntoBit());
//		
//		/* 内部静态类的创建*/
//		NotebookComputer.VideoCard vc = new NotebookComputer.VideoCard();
//		
//		vc.showMessage("我是内部静态类");}
}

运行结果