import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 public class Demo4 {

     public static void main(String[] args) {

         // TODO Auto-generated method stub

         getFile();

     }

     public static void getFile() {

         //1.找到目标文件

         File file = new File("D:\\a.txt");

         //2.建立通道

         FileInputStream inputStream = null;

         try {

             inputStream = new FileInputStream(file);

             byte[] b = new byte[1024];

             try {

                 int count = inputStream.read(b);

                 System.out.println(new String(b,0,count));

             } catch (IOException e) {

                 System.out.println("硬盘损坏了,请修理");

                 throw new RuntimeException(e);

             }

         } catch (FileNotFoundException e) {

             System.out.println("文件不存在");

             //提示用户有错误要修改

             //让后面的代码定制运行

             //System.exit(0); 不太好，一般是不随意推出虚拟机。

             throw new RuntimeException(e);  //创建一个运行时异常

         }finally {

             try {

                 inputStream.close();

             } catch (IOException e) {

                 System.out.println("关闭失败");

                 throw new RuntimeException(e);

             }

         }

     }

 }