【java】io流之字节输入流：java.io.InputStream类及子类java.io.FileInputStream

package 文件操作;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class TestInputStream {
    public static void main(String[] args) throws IOException {
        File file=new File("D:"+File.separator+"test.txt");
        
        /*一次性读取文件内容
        if(file.exists()){
            InputStream inputStream=new FileInputStream(file);
            byte[] bytes=new byte[1024];
            int length=inputStream.read(bytes);
            inputStream.close();
            System.out.println("【"+new String(bytes,0,length)+"】");
        }
        */
        
        if(file.exists()){//单个读取
            InputStream inputStream=new FileInputStream(file);
            byte[] bytes=new byte[1024];
            int foot=0;
            byte tmp=0;
            while((tmp=(byte)inputStream.read())!=-1)
                bytes[foot++]=tmp;
            inputStream.close();
            System.out.println("【"+new String(bytes,0,foot)+"】");
        }
    }
}