<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist SYSTEM "file://localhost/System/Library/DTDs/PropertyList.dtd">
<plist version="0.9">
    <dict>
        ...
        <key>CFBundleURLTypes</key>
        <array>
            <dict>
                <key>CFBundleURLName</key>
                <string>myApp handler</string>
                <key>CFBundleURLSchemes</key>
                <array>
                    <string>myapp</string>
                </array>
            </dict>
        </array>
        ...
    </dict>
</plist>

对于目标C，可以在这里找到答案：通过注册的URL方案启动OSX应用程序时，如何访问完整的URL？

Java的解决方案是将ObjC代码重写为纯C，然后借助下的一组类将其转换为Java org.eclipse.swt.internal.cocoa.*。

作为ObjC到C转换的参考，我们需要Apple的Objective-
C运行时参考
。

普通C版本

首先，让我们翻译

[[NSAppleEventManager sharedAppleEventManager]
    setEventHandler:targetObject
        andSelector:@selector(handleAppleEvent:withReplyEvent:)
      forEventClass:kInternetEventClass
         andEventID:kAEGetURL];

到普通C中。要在普通C中调用ObjC函数，我们使用objc_msgSend()。此外，@selector(method_footprint)用代替，用sel_registerName("method_footprint")查找类objc_getClass()。类型id和SEL等效于指针（例如void
）或完整大小的int（即与void 相同的大小）。

结果：

// id mgr = [NSAppleEventManager sharedAppleEventManager]
SEL sel_ sharedAppleEventManager = sel_registerName("sharedAppleEventManager");
id mgr = objc_msgSend (objc_getClass("NSAppleEventManager"), sharedAppleEventManager);

// and the rest
SEL sel_setEventHandler = sel_registerName("setEventHandler:andSelector:forEventClass:andEventID:");
SEL sel_handleAppleEvent = sel_registerName("handleAppleEvent:withReplyEvent:");
objc_msgSend (mgr, sel_setEventHandler, targetObject, sel_handleAppleEvent, kInternetEventClass, kAEGetURL);

如您所见，我们在这里有两个子例程调用：第一个调用该类的sharedAppleEventManager消息，从NSAppleEventManager该类中检索一个单例对象。第二个调用是将setEventHandler
…消息发送到该对象，并传递4个参数（目标对象，目标消息和两个事件说明符）。

回调函数的声明，最初是：

- (void)handleAppleEvent:(NSAppleEventDescriptor *)event withReplyEvent:(NSAppleEventDescriptor *)replyEvent

在纯C中看起来像这样：

void handleAppleEvent (id self, SEL selector, NSAppleEventDescriptor* event, NSAppleEventDescriptor* replyEvent)

这意味着调用该函数时，不仅会发送其对象引用（id），而且还会发送其方法足迹（选择器）。

在ObjC中，回调代码如下所示以获取URL：

NSString url = [[event paramDescriptorForKeyword:keyDirectObject] stringValue];

在纯C中：

id desc_id = objc_msgSend (event_id, sel_registerName("paramDescriptorForKeyword:"), '----');
id url_id = objc_msgSend (desc_id, desc_id, sel_registerName("stringValue"));

仍然缺少一部分：

targetObject需要在调用上面的代码之前进行初始化，并且handleAppleEvent:withReplyEvent:需要在该目标对象中创建与足迹匹配的方法，然后将其链接到我们的普通C事件处理程序（handleAppleEvent()）。

这意味着我们必须创建一个Objective C类，向其添加一个方法，然后为其创建一个对象实例：

// create an NSObject subclass for our target object
char objcClassName[] = "ObjCAppleEventHandler";
id objcClass = objc_allocateClassPair (objc_getClass("NSObject"), objcClassName);

// add the callback method to the class
SEL sel_handleAppleEvent = sel_registerName("handleAppleEvent:withReplyEvent:");
class_addMethod (objcClass, sel_handleAppleEvent, handleAppleEvent, "i@:@@");

// register the class
objc_registerClassPair (objcClass)

// create an object instance
id targetObject = class_createInstance (objcClass, 0);

// ... here follows the above code with the setEventHandler invocation
// (note: `SEL sel_handleAppleEvent` appears twice - the 2nd one can be removed)

到此结束纯C版本。

（注意：上面的代码未经测试就编写，因此可能包含错误。但是，下面的Java代码已经过测试。）

Java版本

从Plain C到Java的转换现在非常简单。

前面提到的ObjC Runtime函数都可以从org.eclipse.swt.internal.cocoa.OS获得。

首先，一些预设：

static final long class_NSAppleEventManager = OS.objc_getClass("NSAppleEventManager");
static final long sel_sharedAppleEventManager = OS.sel_registerName("sharedAppleEventManager");
static final long sel_setEventHandler = OS.sel_registerName("setEventHandler:andSelector:forEventClass:andEventID:");
static final long sel_handleAppleEvent = OS.sel_registerName("handleAppleEvent:withReplyEvent:");
static final long sel_paramDescriptorForKeyword = OS.sel_registerName("paramDescriptorForKeyword:");
static final long sel_stringValue = OS.sel_registerName("stringValue");

static final long kInternetEventClass = 0x4755524C; // 'GURL'
static final long kAEGetURL = 0x4755524C; // 'GURL'
static final long kCoreEventClass = 0x61657674; // 'aevt'
static final long kAEOpenApplication = 0x6F617070; // 'oapp'
static final long kAEReopenApplication = 0x72617070; // 'rapp'
static final long keyDirectObject = 0x2d2d2d2d; // '----'

回调函数：

static long handleAppleEvent (long id, long sel, long event_id, long reply_id) {
    // This is a handler for AppleEvents that are registered with [NSAppleEventManager setEventHandler:...]
    // It matches this selector (footprint):
    //   - (void)handleAppleEvent:(NSAppleEventDescriptor *)event withReplyEvent:(NSAppleEventDescriptor *)reply

    // Invoke [[event paramDescriptorForKeyword:keyDirectObject] stringValue] to get the direct object containing the URL
    long direct_desc_id = OS.objc_msgSend (event_id, sel_paramDescriptorForKeyword, keyDirectObject);
    long direct_str_id = OS.objc_msgSend (direct_desc_id, sel_stringValue);
    NSString nsStr = new NSString (direct_str_id);
    String str = nsStr.getString();
    // now 'str' contains the URL

    System.out.println ("handleAppleEvent invoked -- argument: "+url);
    return 0;
}

和注册回调函数的代码：

// Get access to a callback function for receiving the sel_handleAppleEvent message
aeCallback = new Callback(Main.class, "handleAppleEvent", 4);
long aeProc = aeCallback.getAddress();

// Create a ObjC class that provides a method with the sel_handleAppleEvent footprint
String objcClassName = "ObjCAppleEventHandler";
long objcClass = OS.objc_allocateClassPair(OS.class_NSObject, objcClassName, 0);
OS.class_addMethod(objcClass, sel_handleAppleEvent, aeProc, "i@:@@");
OS.objc_registerClassPair(objcClass);
long objcHandlerInstance = OS.class_createInstance (objcClass, 0);

// Invoke [[NSAppleEventManager sharedAppleEventManager] setEventHandler:objcHandlerInstance andSelector:sel_handleAppleEvent forEventClass:kInternetEventClass andEventID:kAEGetURL]
long sharedAppleEventMgr = OS.objc_msgSend (class_NSAppleEventManager, sel_sharedAppleEventManager);
OS.objc_msgSend (sharedAppleEventMgr, sel_setEventHandler, objcHandlerInstance, sel_handleAppleEvent, kInternetEventClass, kAEGetURL);

剩下要做的就是根据此代码构建应用程序捆绑包，然后将CFBundleURLTypes条目添加到其Info.plist中。

完整的示例源文件可以在这里下载：http : //files.tempel.org/Various/ObjectiveC-
bridging.java.zip