先贴个代码
public static void downloadFile(String remoteFilePath, String localFilePath) {
File remoteFile = new File(remoteFilePath);
File localFile = new File(localFilePath);
FileInputStream fis = null;
FileOutputStream fos = null;
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
byte[] buffer=null;
try {
// 输入输出流对象
fis = new FileInputStream(remoteFile);
bis=new BufferedInputStream(fis);
fos = new FileOutputStream(localFile);
bos=new BufferedOutputStream(fos);
System.out.println("源目录" + remoteFile.getPath());
System.out.println("目标目录" + localFile.getPath());
int len = 0;
buffer = new byte[1024];
while ((len = bis.read(buffer)) > -1) {
System.out.println("len=" + len);
// fos.write(buffer, 0, len);
bos.write(buffer, 0, len);
}
bos.flush();
System.out.println("最后一次len=" + len);
System.out.println("下载成功");
} catch (Exception e) {
e.printStackTrace();
} finally {
if (fis != null) {
try {
fis.close();
System.out.println("fis.close");
} catch (IOException e) {
e.printStackTrace();
}
}
if (fos != null) {
try {
fos.close();
System.out.println("fos.close");
} catch (IOException e) {
e.printStackTrace();
}
}if (bis != null) {
try {
bis.close();
System.out.println("bis.close");
} catch (IOException e) {
e.printStackTrace();
}
}
if (bos != null) {
try {
bos.close();
System.out.println("bos.close");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
上述代码中，特别要注意加粗的部分,
当我fos.write(buffer, 0, len);执行后，直接fos.close();时，文件也能写到硬盘上；
当我bos.write(buffer, 0, len);执行后，直接bos.close();时，文件却不能写到硬盘上，在bos.close()；之前必须先bos.flush()；
查询API文档后发现
FileOutputStream:
BufferedOutputStream：
在这里走了一点冤枉路，现作为提醒自己，写个记录。。。