字节流---输入输出

shimeath

发布于 2020-07-30 18:41:31

3770

发布于 2020-07-30 18:41:31

文章被收录于专栏：shimeath的Java学习

流的输入及输出均是对程序而言

字节流输入

创建File对象，关联文件

File src = new File("D:/aa", "a.txt");

1)、创建以src为输入流的对象，

Inputstream in = new FileInputStream(src);

2)、建立字节数组(byte[])，创建长度整形变量len

byte[] car = new byte[10];
int len = 0;

3)、读取输入流，将byte[]转换为String并输出

while (-1 != (len = in.read(car))) {
	String info = new String(car, 0, len);
	System.out.println(info);
}

read()返回读入长度，为-1时结束

2. 4)、读取结束后关闭输入流

in.close();

进行异常处理

try {
	in = new FileInputStream(src);
	byte[] car = new byte[10];
	int len = 0;
	while (-1 != (len = in.read(car))) {
		String info = new String(car, 0, len);
		System.out.println(info);
	}
} catch (FileNotFoundException e) {
	System.out.println("文件读取失败");
} catch (IOException e) {
	System.out.println("文件流操作失败");
} finally {
	if (in != null) {
		try {
			in.close();
		} catch (IOException e) {
			System.out.println("关闭输入流失败");
		}
	}
}

字节流输出

创建File对象，关联文件

File src = new File("D:/aa", "a.txt");

1)、创建以src为输出流的对象，

Outputstream in = new FileOutputStream(src);

2)、建立字符串，转换为字节数组并写入

String str = "simple\n";
out.write(str.getBytes());

3)、刷新输出流

out.flush();

flush()方法使流中的数据写入文件

2. 4)、读取结束后关闭输出流

out.close();

进行异常处理

try {
	out = new FileOutputStream(src, true);
	String str = "simple\n";
	out.write(str.getBytes());
	out.flush();
} catch (FileNotFoundException e) {
	System.out.println("文件不存在");
} catch (IOException e) {
	System.out.println("文件流操作失败");
} finally {
	if (out != null) {
		try {
			out.close();
		} catch (IOException e) {
			System.out.println("关闭输出流失败");
		}
	}
}

完整代码(输入)：

package cn.hxh.io.filebyte;

import java.io.*;

public class myInputStream {

	public static void main(String[] args) {
		File src = new File("D:/aa", "a.txt");
		InputStream in = null;
		try {
			in = new FileInputStream(src);
			byte[] car = new byte[10];
			int len = 0;
			while (-1 != (len = in.read(car))) {
				String info = new String(car, 0, len);
				System.out.println(info);
			}
		} catch (FileNotFoundException e) {
			System.out.println("文件读取失败");
		} catch (IOException e) {
			System.out.println("文件流操作失败");
		} finally {
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					System.out.println("关闭输入流失败");
				}
			}
		}
	}

}

完整代码(输出)：

package cn.hxh.io.filebyte;

import java.io.*;

public class myOutputStream {

	public static void main(String[] args) {
		File src = new File("D:/aa", "a.txt");
		OutputStream out = null;
		try {
			out = new FileOutputStream(src, true);
			String str = "simple\n";
			out.write(str.getBytes());
			out.flush();
		} catch (FileNotFoundException e) {
			System.out.println("文件不存在");
		} catch (IOException e) {
			System.out.println("文件流操作失败");
		} finally {
			if (out != null) {
				try {
					out.close();
				} catch (IOException e) {
					System.out.println("关闭输出流失败");
				}
			}
		}
	}

}

本文参与腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。

原始发表：2020-01-26 ，如有侵权请联系 cloudcommunity@tencent.com 删除

byte