如何打开与默认关联程序的文件

You can use Desktop.getDesktop().open(File file). See the following question for other options: "[Java] How to open user system preffered editor for given file?"

SwingHacks has a solution for older versions of Java.

I think they used the Runtime object to execute the 'start' command on windows and there is a similar command on the mac.

Here you go:

File myFile = new File("your any type of file url");
FileOpen.openFile(mContext, myFile);

Create a different class within the package:

// code to open default application present in the handset




public class FileOpen {


public static void openFile(Context context, File url) throws IOException {
// Create URI
File file=url;
Uri uri = Uri.fromFile(file);


Intent intent = new Intent(Intent.ACTION_VIEW);
// Check what kind of file you are trying to open, by comparing the url with extensions.
// When the if condition is matched, plugin sets the correct intent (mime) type,
// so Android knew what application to use to open the file
if (url.toString().contains(".doc") || url.toString().contains(".docx")) {
// Word document
intent.setDataAndType(uri, "application/msword");
} else if(url.toString().contains(".pdf")) {
// PDF file
intent.setDataAndType(uri, "application/pdf");
} else if(url.toString().contains(".ppt") || url.toString().contains(".pptx")) {
// Powerpoint file
intent.setDataAndType(uri, "application/vnd.ms-powerpoint");
} else if(url.toString().contains(".xls") || url.toString().contains(".xlsx")) {
// Excel file
intent.setDataAndType(uri, "application/vnd.ms-excel");
} else if(url.toString().contains(".zip") || url.toString().contains(".rar")) {
// WAV audio file
intent.setDataAndType(uri, "application/x-wav");
} else if(url.toString().contains(".rtf")) {
// RTF file
intent.setDataAndType(uri, "application/rtf");
} else if(url.toString().contains(".wav") || url.toString().contains(".mp3")) {
// WAV audio file
intent.setDataAndType(uri, "audio/x-wav");
} else if(url.toString().contains(".gif")) {
// GIF file
intent.setDataAndType(uri, "image/gif");
} else if(url.toString().contains(".jpg") || url.toString().contains(".jpeg") || url.toString().contains(".png")) {
// JPG file
intent.setDataAndType(uri, "image/jpeg");
} else if(url.toString().contains(".txt")) {
// Text file
intent.setDataAndType(uri, "text/plain");
} else if(url.toString().contains(".3gp") || url.toString().contains(".mpg") || url.toString().contains(".mpeg") || url.toString().contains(".mpe") || url.toString().contains(".mp4") || url.toString().contains(".avi")) {
// Video files
intent.setDataAndType(uri, "video/*");
} else {
//if you want you can also define the intent type for any other file


//additionally use else clause below, to manage other unknown extensions
//in this case, Android will show all applications installed on the device
//so you can choose which application to use
intent.setDataAndType(uri, "*/*");
}


intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
}
}

few examples to open files with default program

Example 1 : Runtime.getRuntime().exec("rundll32.exe shell32.dll ShellExec_RunDLL " + fileName);
Example 2 : Runtime.getRuntime().exec("rundll32.exe url.dll FileProtocolHandler " + fileName);
Example 3 : Desktop.getDesktop().open(fileName);




alternative...


Runtime.getRuntime().exec(fileName.toString());
Runtime.getRuntime().exec("cmd.exe /c Start " + fileName);
Runtime.getRuntime().exec("powershell.exe /c Start " + fileName);
Runtime.getRuntime().exec("explorer.exe " + fileName);
Runtime.getRuntime().exec("rundll32.exe SHELL32.DLL,OpenAs_RunDLL " + fileName);

Or....

public static void openFile(int selecType, File fileName) throws Exception {


String[] commandText = null;


if (!fileName.exists()) {
JOptionPane.showMessageDialog(null, "File not found", "Error", 1);
} else {


switch (selecType) {
case 0:
//Default function
break;
case 1:
commandText = new String[]{"rundll32.exe", "shell32.dll", "ShellExec_RunDLL", fileName.getAbsolutePath()};
break;
case 2:
commandText = new String[]{"rundll32.exe", "url.dll", "FileProtocolHandler", fileName.getAbsolutePath()};
break;
case 3:
commandText = new String[]{fileName.toString()};
break;
case 4:
commandText = new String[]{"cmd.exe", "/c", "Start", fileName.getAbsolutePath()};
break;
case 5:
commandText = new String[]{"powershell.exe", "/c", "Start", fileName.getAbsolutePath()};
break;
case 6:
commandText = new String[]{"explorer.exe", fileName.getAbsolutePath()};
break;
case 7:
commandText = new String[]{"rundll32.exe", "shell32.dll", "OpenAs_RunDLL", fileName.getAbsolutePath()}; //File open With
break;
}


if (selecType == 0) {
Desktop.getDesktop().open(fileName);
} else if (selecType < 8) {
Process runFile = new ProcessBuilder(commandText).start();
runFile.waitFor();
} else {
String errorText = "\nChoose a number from 1 to 7\n\nExample : openFile(1,\"" + fileName + "\")\n\n";
System.err.println(errorText);
JOptionPane.showMessageDialog(null, errorText, "Error", 1);
}


}


}