ReadFromFile

package java_learning;
import java.io.*;
public class ReadFromFile {
	 public static void main(String[] args) throws IOException {
	       String fileName="F:"+File.separator+"hello.txt";
	       File f = new File(fileName);
	       InputStream in = new FileInputStream(f);
	       //byte[] b = new byte[(int)f.length()];
	       byte[] b = new byte[1024];
	       int count = 0;
	       int temp =0;
	       while((temp = in.read()) != -1){//当读到文件末尾的时候会返回-1
	    	   b[count++] = (byte)temp;
	       }
	      // int len=in.read(b);
	       in.close();
	       System.out.println("文件长度为："+f.length());
	       System.out.println("读数据长度为："+count);
	       System.out.println(new String(b, 0, count));
	  }
}