JAVA文件读取

public static byte[] getBytesFromFile(File file) throws IOException {
InputStream is = new FileInputStream(file);
// 获取文件大小
long length = file.length();
if (length > Integer.MAX_VALUE) {
// 文件太大，无法读取
throw new IOException("File is to large " + file.getName());
}
// 创建一个数据来保存文件数据
byte[] bytes = new byte[(int) length];
// 读取数据到byte数组中
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
offset += numRead;
}
// 确保所有数据均被读取
if (offset < bytes.length) {
throw new IOException("Could not completely read file "
+ file.getName());
}
// Close the input stream and return bytes
is.close();
return bytes;
}