java 使用 JFileChooser 保存对话框保存文件
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Saving files with JFileChooser save dialog
提问by samuel
I have a class that opens the files with this part:
我有一个类可以用这部分打开文件：
JFileChooser chooser=new JFileChooser();
chooser.setCurrentDirectory(new File("."));
int r = chooser.showOpenDialog(ChatFrame.this);
if (r != JFileChooser.APPROVE_OPTION) return;
try {
Login.is.sendFile(chooser.getSelectedFile(), Login.username,label_1.getText());
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
then I want to save this file in another file with:
然后我想将此文件保存在另一个文件中：
JFileChooser jfc = new JFileChooser();
int result = jfc.showSaveDialog(this);
if (result == JFileChooser.CANCEL_OPTION)
return;
File file = jfc.getSelectedFile();
InputStream in;
try {
in = new FileInputStream(f);
OutputStream st=new FileOutputStream(jfc.getSelectedFile());
st.write(in.read());
st.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
but it only creates an empty file! what should I do to solve this problem? (I want my class to open all kind of files and save them)
但它只会创建一个空文件！我该怎么做才能解决这个问题？（我想让我的班级打开所有类型的文件并保存它们）
回答by fasseg
here's your problem: in.read() only reads one byte from the Stream but youll have to scan through the whole Stream to actually copy the file:
这是您的问题： in.read() 仅从流中读取一个字节，但您必须扫描整个流才能实际复制文件：
OutputStream st=new FileOutputStream(jfc.getSelectedFile());
byte[] buffer=new byte[1024];
int bytesRead=0;
while ((bytesRead=in.read(buffer))>0){
st.write(buffer,bytesRead,0);
}
st.flush();
in.close();
st.close();
or with a helper from apache-commons-io:
或使用apache-commons-io的助手：
OutputStream st=new FileOutputStream(jfc.getSelectedFile());
IOUtils.copy(in,st);
in.close();
st.close();
回答by amit
You have to read from intill the end of file. Currently you perform just one read. See for example: http://www.java-examples.com/read-file-using-fileinputstream
您必须从in文件末尾读取。目前您只执行一次读取。参见例如：http: //www.java-examples.com/read-file-using-fileinputstream
