Java + JNA, looking for a way to run ShellExecuteW

Question

I am trying to run a ShellExecute function from java with JNA. I dont have any problems running ShellExecuteA on non-unicode folders

import com.sun.jna.*;
import com.sun.jna.platform.win32.ShellAPI;
import com.sun.jna.platform.win32.WinDef;
import com.sun.jna.win32.*;

public class Main {
    public interface Shell32 extends ShellAPI, StdCallLibrary {
        Shell32 INSTANCE = (Shell32)Native.loadLibrary("shell32", Shell32.class);

        WinDef.HINSTANCE ShellExecuteA(WinDef.HWND hwnd,
                                      String lpOperation,
                                      String lpFile,
                                      String lpParameters,
                                      String lpDirectory,
                                      int nShowCmd);
    }

    public static void main(String[] args) {
        WinDef.HWND h = null;
        WString st = new WString("D:");
        Shell32.INSTANCE.ShellExecuteA(h, "open", st.toString(), null, null, 1);

    }
}

But since I want to be able to use it on unicode folders I actually want to run ShellExecuteW instead of A version, but cant figure how. Every time I run the following code it just finishes executing without doing anything or showing any errors.

import com.sun.jna.*;
import com.sun.jna.platform.win32.ShellAPI;
import com.sun.jna.platform.win32.WinDef;
import com.sun.jna.win32.*;

public class Main {
    public interface Shell32 extends ShellAPI, StdCallLibrary {
        Shell32 INSTANCE = (Shell32)Native.loadLibrary("shell32", Shell32.class);

        WinDef.HINSTANCE ShellExecuteW(WinDef.HWND hwnd,
                                      String lpOperation,
                                      WString lpFile,
                                      String lpParameters,
                                      String lpDirectory,
                                      int nShowCmd);
    }

    public static void main(String[] args) {
        WinDef.HWND h = null;
        WString st = new WString("D:\\日本語");
        Shell32.INSTANCE.ShellExecuteW(h, "open", st, null, null, 1);

    }
}

I guess the problem lies withing the third parameter lpFile - I tried using String, WString all the same. Any help will be appreciated.

Thanks.

You don't check for errors, so why would you expect any? Read the documentation of the function you are calling to learn how to test for errors. — David Heffernan, Jun 10 '15 at 10:35
If you're going to explicitly use wide strings, you typically need to use them for _all_ function parameters. w32 API will typically have `LPTCSTR` for all C strings, which means `String` for ascii and `WString` for unicode. — technomage, Jun 10 '15 at 15:20

score 0 · Answer 1 · answered Sep 01 '18 at 15:58

Because this is the answer I repeat @technomage's comment to the question here:

If you're going to explicitly use wide strings, you typically need to use them for all function parameters. w32 API will typically have LPTCSTR for all C strings, which means String for ascii and WString for unicode.

The working code is therefore:

import com.sun.jna.*;
import com.sun.jna.platform.win32.ShellAPI;
import com.sun.jna.platform.win32.WinDef;
import com.sun.jna.win32.*;

public class Main {
    public interface Shell32 extends ShellAPI, StdCallLibrary {
        Shell32 INSTANCE = (Shell32)Native.loadLibrary("shell32", Shell32.class);

        WinDef.HINSTANCE ShellExecuteW(WinDef.HWND hwnd,
                                      WString lpOperation,
                                      WString lpFile,
                                      WString lpParameters,
                                      WString lpDirectory,
                                      int nShowCmd);
    }

    public static void main(String[] args) {
        WinDef.HWND h = null;
        WString file = new WString("D:\\日本語");
        Shell32.INSTANCE.ShellExecuteW(h, new WString("open"), file, null, null, 1);
    }
}

Java + JNA, looking for a way to run ShellExecuteW

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