JavaIO流内部异常处理

完成⼀个⽂件的拷⻉

1. 写法⼀(以前内容)

try {
 FileInputStream fis = new FileInputStream("xdclass.txt");
 BufferedInputStream bis = new BufferedInputStream(fis);
 FileOutputStream fos = new FileOutputStream("copy.txt");
 BufferedOutputStream bos = new BufferedOutputStream(fos);
 int size;
 byte[] buf = new byte[1024];
 while ((size = bis.read(buf)) != -1) {
 bos.write(buf, 0, size);
 }
 //刷新此缓冲的输出流，才可以保证数据全部输出完成,close会⾃动关闭
 //bos.flush();
 //关闭的时候只需要关闭最外层的流就⾏了，源码⾥⾯会⾃动关闭inputstream对象的
 bis.close();
 bos.close();
 } catch (Exception e) {
 e.printStackTrace();
 }

2. 写法⼆(JDK6之前，⼤部分⼈还停留这个写法)

BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
FileInputStream fis = new FileInputStream("xdclass.txt");
bis = new BufferedInputStream(fis);
FileOutputStream fos = new FileOutputStream("copy.txt");
bos = new BufferedOutputStream(fos);
int size;
byte[] buf = new byte[1024];
while ((size = bis.read(buf)) != -1) {
bos.write(buf, 0, size);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (bos != null) {
try {
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}