JAVA IO处理文件的常用方法

JAVA IO 处理文件根据输入，输出主要使用的类：

Reader InputStream   InputStreamReader
Writer OutputStream  OutputStreamWriter

PrintWriter PrintSteam

1，拷贝纯文本文件，使用默认的编码格式GBK

BufferedReader br = new BufferedReader(new FileReader("a.txt"));
BufferedWriter bw = new BufferedWriter(new FileWriter("b.txt"));


2, 拷贝二进制文件（视频，音频，图片等）
BufferedInputStream fis = new BufferedInputStream(new FileInputStream("1.jpg"));
BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream("2.jpg"));


3，流文件转换成字符文件
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bw = new BufferedWriter(new FileWriter("b.txt"));


4，字符文件转换成流文件
BufferedReader br = new BufferedReader(new FileReader("a.txt"));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));


5, 如果考虑字符编码就使用字节字符转换桥梁（InputStreamReader， OutputStreamWriter）
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("1.txt"), "utf-8"));