IO_FileInputStream&FileOutputStream

通过available()方法实现不阻塞输入流

		FileInputStream fis = new FileInputStream(f);
		try {
			//通过available()方法可以实现不阻塞流
			byte[] b = new byte[fis.available()];
			int result = 0;
			while((result = fis.read(b)) != -1) {
				System.out.println(new String(b, "utf-8"));
			}
		
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		fis.close();

读取文件

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

public class FileInputStreamJava {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		String strFile = "d:" + File.separator + "javatest" + File.separator + "IO_RandomAccessFileTest.txt";
		File f = new File(strFile);
		FileInputStream fis = new FileInputStream(f);
		byte[] b = new byte[1024];
		int result = 0;
		while((result = fis.read(b)) != -1) {
			//数组b固定大小1024，所以如果读到的数据不足，数组会自动填满，输出的时候结尾就可能会出现乱码
			//下面这种方式就出现了乱码
			//System.out.println(new String(b, "utf-8"));
			//现在这样就不会出现乱码了，重新组装成字符串的时候确定了最后一个字符串的byte数组大小
			System.out.println(new String(b,0,result, "utf-8"));
		}
		fis.close();
	}
}

每次读一个字节

public class FileInputStreamJava {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		String strFile = "d:" + File.separator + "javatest" + File.separator + "IO_RandomAccessFileTest.txt";
		File f = new File(strFile);
		FileInputStream fis = new FileInputStream(f);
		//byte[] b = new byte[1024];
		int result = 0;
		while((result = fis.read()) != -1) {
			//数组b固定大小1024，所以如果读到的数据不足，数组会自动填满，输出的时候结尾就可能会出现乱码
			//下面这种方式就出现了乱码
			//System.out.println(new String(b, "utf-8"));
			//现在这样就不会出现乱码了，重新组装成字符串的时候确定了最后一个字符串的byte数组大小
			System.out.print((char)result);
		}
		fis.close();
	}
}

写数据

import java.io.File;
import java.io.FileOutputStream;

public class FileOutputStreamJava {

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		String strFile = "d:" + File.separator + "javatest" + File.separator + "IO_RandomAccessFileTest.txt";
		File f = new File(strFile);
		//true，将字节写入文件末尾处，而不是写入文件开始处 
		FileOutputStream fos = new FileOutputStream(f, true);
		//  \r\n是windows系统的换行符
		byte[] b = "\r\n写出数据...".getBytes();
		fos.write(b);
		fos.close();
	}

}