FileOutputStream删除文件内容
FileOutputStream删除文件内容
提问于 2016-06-09 08:44:16
嗨，我想用FileOutputStream通过网络发送数据。每当使用链接的文件创建FileOutputStream时，它就删除了发现的所有数据，就好像用新的文件替换旧文件一样。
有人能帮忙吗？这是密码。
File videoFile = new File (Current_video_file);
log.info(videoFile.toString());
InputStream is = null;
OutputStream outS = null;
try{
is = socket.getInputStream();
} catch (IOException e){
e.printStackTrace();
}
try{
outS = new FileOutputStream(videoFile);
} catch (IOException e){
e.printStackTrace();
}
byte [] videoLength = new byte [16*1024];
log.info("About to send");
int count;
while((count = is.read(videoLength)) > 0){
log.info("Sending Message");
outS.write(videoLength, 0, count);
}
log.info("Data Sent");
outS.close();
is.close();回答 2
Stack Overflow用户
回答已采纳
发布于 2016-06-09 08:53:36
JavaDoc说：
/**
* Creates a file output stream to write to the file represented by
* the specified <code>File</code> object. If the second argument is
* <code>true</code>, then bytes will be written to the end of the file
* rather than the beginning. A new <code>FileDescriptor</code> object is
* created to represent this file connection.
* <p>
* First, if there is a security manager, its <code>checkWrite</code>
* method is called with the path represented by the <code>file</code>
* argument as its argument.
* <p>
* If the file exists but is a directory rather than a regular file, does
* not exist but cannot be created, or cannot be opened for any other
* reason then a <code>FileNotFoundException</code> is thrown.
*
* @param file the file to be opened for writing.
* @param append if <code>true</code>, then bytes will be written
* to the end of the file rather than the beginning
* @exception FileNotFoundException if the file exists but is a directory
* rather than a regular file, does not exist but cannot
* be created, or cannot be opened for any other reason
* @exception SecurityException if a security manager exists and its
* <code>checkWrite</code> method denies write access
* to the file.
* @see java.io.File#getPath()
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkWrite(java.lang.String)
* @since 1.4
*/
public FileOutputStream(File file, boolean append)因此，要使用它，您应该在FileOutputStream的构造函数中添加一个布尔值，将True添加到追加，或将False添加到覆盖
所以您的代码应该如下所示：
Boolean append = true;
outS = new FileOutputStream(videoFile, append);Stack Overflow用户
发布于 2016-06-09 08:52:37
还有第二个参数可用于FileOutputStream的构造函数。如果为true，它将在文件末尾追加数据；如果为false，则将替换内容。默认情况下是假的。
因此，您只需更改FileOutputStream的声明：
outS = new FileOutputStream(videoFile, true); 页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/37720979
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