使用JNA进行C回调会导致JRE崩溃
我在JNA中处理回调时遇到问题。
我正在尝试使用一个使用回调来处理多个会话事件的C API（登录，注销，连接问题……）。
会话对象（称为sp_session ）是一个不透明的结构。 所有回调都在sp_session_callbacks结构中注册。 根据API，我应该声明回调对象，并将其放入我将在创建sp_session对象时提供的sp_session对象中。 如果我不想使用某些回调，我应该用null初始化它们。 API使用__stdcall调用约定。
这是与我的问题相关的C标题的片段：
#define SP_CALLCONV __stdcall typedef struct sp_session sp_session; ///< Representation of a session typedef enum sp_error { SP_ERROR_OK = 0, SP_ERROR_BAD_API_VERSION = 1, /* More errors */ } sp_error; typedef struct sp_session_callbacks { /** * Called when login has been processed and was successful */ void (SP_CALLCONV *logged_in)(sp_session *session, sp_error error); /** * Called when logout has been processed. Either called explicitly * if you initialize a logout operation, or implicitly if there * is a permanent connection error * * @param[in] session Session */ void (SP_CALLCONV *logged_out)(sp_session *session); /** * Called when there is a connection error, and the library has problems * reconnecting to the Spotify service. Could be called multiple times (as * long as the problem is present) */ void (SP_CALLCONV *connection_error)(sp_session *session, sp_error error); /* More callbacks */ } sp_session_callbacks; /** * Initialize a session. The session returned will be initialized, but you will need * to log in before you can perform any other operation */ SP_LIBEXPORT(sp_error) sp_session_create(const sp_session_config *config, sp_session **sess);
这是我的等效JNA代码：
sp_session对象
public class sp_session extends PointerType{ public sp_session(Pointer address) { super(address); } public sp_session() { super(); } }
sp_session_callbacks对象，包含所有回调
public class sp_session_callbacks extends Structure{ public LoggedIn logged_in; public LoggedOut logged_out; public ConnectionError connection_error; }
回调对象（这里是LoggedIn，但我当然每个回调都有一个）
public interface LoggedIn extends StdCallCallback { public void logged_in(sp_session session, int error); }
本机库，声明所有方法
public interface JLibspotify extends StdCallLibrary{ int sessionCreate(sp_session_config config, PointerByReference sess); int sessionLogin(sp_session session, String username, String password); // All the other methods defined by the API }
而我的主要课程，将它们捆绑在一起
public class Test{ static{ System.loadLibrary("libspotify"); } public static void main(String[] args){ JLibspotify lib = (JLibspotify)Native.loadLibrary("libspotify", JLibspotify.class); sp_session_config cfg = new sp_session_config(); } sp_session_callbacks sessCallbacks = new sp_session_callbacks(); LoggedIn loggedInCallback = new LoggedIn(){ public void logged_in(sp_session session, int error) { System.out.println("logged_in() called"); } }; sessCallbacks.logged_in = loggedInCallback; cfg.session_callbacks = sessCallbacks; PointerByReference sessionPbr = new PointerByReference(); int error_id = sessionCreate(cfg, sessionPbr); // CRASHES HERE sp_session mySession = new sp_session(sessionPbr.getValue()); } }
因此，sessionCreate函数调用使得JRE崩溃，并在EXCEPTION_ACCESS_VIOLATION (0xc0000005) problematic frame: C [jna3666290841889849729.dll+0xa3f4]结尾处跟踪EXCEPTION_ACCESS_VIOLATION (0xc0000005) problematic frame: C [jna3666290841889849729.dll+0xa3f4] 。
看起来像logged_in回调导致这种情况，因为当我将它设置为null它运行正常。 另外，如果我初始化connection_error回调，它具有完全相同的签名，它也不会崩溃。
我正在运行JNA的3.2.7版本。 我尝试使用前版（3.0.9），但也失败了。 我正在运行JDK 1.7测试版，但我尝试使用1.6并且它也失败了。
谢谢！
# # A fatal error has been detected by the Java Runtime Environment: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0499a3f4, pid=1368, tid=1344 # # JRE version: 7.0-b129 # Java VM: Java HotSpot(TM) Client VM (21.0-b01 mixed mode, sharing windows-x86 ) # Problematic frame: # C [jna3666290841889849729.dll+0xa3f4] # # If you would like to submit a bug report, please visit: # http://java.sun.com/webapps/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # --------------- THREAD --------------- Current thread (0x01b79400): JavaThread "main" [_thread_in_native, id=1344, stack(0x00340000,0x00390000)] siginfo: ExceptionCode=0xc0000005, reading address 0x1993053a Registers: EAX=0x19930522, EBX=0x100dc77c, ECX=0x00010004, EDX=0x1008d3e0 ESP=0x0038f58c, EBP=0x0038f5b4, ESI=0x0038f5a4, EDI=0x100b79b0 EIP=0x0499a3f4, EFLAGS=0x00210212 Top of Stack: (sp=0x0038f58c) 0x0038f58c: 100dc77c 0038f5a4 00010004 0038f688 0x0038f59c: 05983de0 05981330 0598289c 05983de0 0x0038f5ac: 05983de0 00000014 0038f688 1008d3ea 0x0038f5bc: 05983de0 10030d77 0038fc44 100b79b0 0x0038f5cc: ffffffff 1008d334 00000000 05983de0 0x0038f5dc: 1008d3e0 05983fc4 1008d9fd 0038f770 0x0038f5ec: 00000000 00000000 7275016a 055310b0 0x0038f5fc: 00000000 00010001 00000000 00000000 Instructions: (pc=0x0499a3f4) 0x0499a3d4: 01 00 89 e5 57 56 8d 75 f0 53 83 ec 1c 8b 7d 14 0x0499a3e4: 8b 5f 4c 8b 03 89 4c 24 08 89 74 24 04 89 1c 24 0x0499a3f4: ff 50 18 83 ec 0c 85 c0 0f 94 c0 0f b6 c0 85 c0 0x0499a404: 89 45 ec 75 19 8b 03 31 d2 89 54 24 08 89 74 24 Register to memory mapping: EAX=0x19930522 is an unknown value EBX=0x100dc77c is an unknown value ECX=0x00010004 is an unknown value EDX=0x1008d3e0 is an unknown value ESP=0x0038f58c is pointing into the stack for thread: 0x01b79400 EBP=0x0038f5b4 is pointing into the stack for thread: 0x01b79400 ESI=0x0038f5a4 is pointing into the stack for thread: 0x01b79400 EDI=0x100b79b0 is an unknown value Stack: [0x00340000,0x00390000], sp=0x0038f58c, free space=317k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [jna3666290841889849729.dll+0xa3f4] Java_com_sun_jna_Native_initialize_1ffi_1type+0x1054 C [libspotify.dll+0x8d3ea] sp_error_message+0x35a C [jna3666290841889849729.dll+0xcb77] Java_com_sun_jna_Native_initialize_1ffi_1type+0x37d7 C [jna3666290841889849729.dll+0xc7c2] Java_com_sun_jna_Native_initialize_1ffi_1type+0x3422 C [jna3666290841889849729.dll+0x4561] Java_com_sun_jna_Pointer__1getString+0xa31 C [jna3666290841889849729.dll+0x4d2e] Java_com_sun_jna_Function_invokeInt+0x2e j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0 j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315 j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214 j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341 j $Proxy0.sp_session_create(Lcom/nbarraille/jspotify/model/sp_session_config;Lcom/sun/jna/ptr/PointerByReference;)I+20 j com.nbarraille.jspotify.main.Test.main([Ljava/lang/String;)V+273 v ~StubRoutines::call_stub V [jvm.dll+0x115f6d] V [jvm.dll+0x1b788e] V [jvm.dll+0x115fed] V [jvm.dll+0xa2507] V [jvm.dll+0xac867] C [javaw.exe+0x209e] C [javaw.exe+0xa23b] C [javaw.exe+0xa2c5] C [kernel32.dll+0x51194] BaseThreadInitThunk+0x12 C [ntdll.dll+0x5b429] RtlInitializeExceptionChain+0x63 C [ntdll.dll+0x5b3fc] RtlInitializeExceptionChain+0x36 Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0 j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315 j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214 j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341 j $Proxy0.sp_session_create(Lcom/nbarraille/jspotify/model/sp_session_config;Lcom/sun/jna/ptr/PointerByReference;)I+20 j com.nbarraille.jspotify.main.Test.main([Ljava/lang/String;)V+273 v ~StubRoutines::call_stub --------------- PROCESS --------------- Java Threads: ( => current thread ) 0x0182fc00 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=4664, stack(0x04170000,0x041c0000)] 0x0182ac00 JavaThread "C1 CompilerThread0" daemon [_thread_blocked, id=1728, stack(0x01b20000,0x01b70000)] 0x01829800 JavaThread "Attach Listener" daemon [_thread_blocked, id=112, stack(0x04020000,0x04070000)] 0x01826400 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=5836, stack(0x03ea0000,0x03ef0000)] 0x01819800 JavaThread "Finalizer" daemon [_thread_blocked, id=4724, stack(0x03f80000,0x03fd0000)] 0x01817800 JavaThread "Reference Handler" daemon [_thread_blocked, id=3940, stack(0x01ad0000,0x01b20000)] =>0x01b79400 JavaThread "main" [_thread_in_native, id=1344, stack(0x00340000,0x00390000)] Other Threads: 0x01816400 VMThread [stack: 0x01a30000,0x01a80000] [id=3876] 0x01843000 WatcherThread [stack: 0x040d0000,0x04120000] [id=4636] VM state:not at safepoint (normal execution) VM Mutex/Monitor currently owned by a thread: None Heap def new generation total 4928K, used 3630K [0x23450000, 0x239a0000, 0x289a0000) eden space 4416K, 82% used [0x23450000, 0x237db858, 0x238a0000) from space 512K, 0% used [0x238a0000, 0x238a0000, 0x23920000) to space 512K, 0% used [0x23920000, 0x23920000, 0x239a0000) tenured generation total 10944K, used 0K [0x289a0000, 0x29450000, 0x33450000) the space 10944K, 0% used [0x289a0000, 0x289a0000, 0x289a0200, 0x29450000) compacting perm gen total 12288K, used 860K [0x33450000, 0x34050000, 0x37450000) the space 12288K, 7% used [0x33450000, 0x33527190, 0x33527200, 0x34050000) ro space 10240K, 43% used [0x37450000, 0x3789ce40, 0x3789d000, 0x37e50000) rw space 12288K, 53% used [0x37e50000, 0x384c2710, 0x384c2800, 0x38a50000) Code Cache [0x01e90000, 0x01f20000, 0x03e90000) total_blobs=234 nmethods=82 adapters=88 free_code_cache=32972224 largest_free_block=0 Dynamic libraries: 0x00880000 - 0x008b0000 C:\Program Files\Java\jdk1.7.0\bin\javaw.exe 0x778f0000 - 0x77a2d000 C:\Windows\SYSTEM32\ntdll.dll 0x77070000 - 0x77144000 C:\Windows\system32\kernel32.dll 0x75cf0000 - 0x75d3a000 C:\Windows\system32\KERNELBASE.dll 0x60000000 - 0x60041000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\midas32.dll 0x61000000 - 0x61028000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_base.m32 0x67000000 - 0x67048000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_nt.m32 0x64000000 - 0x64021000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_registry.m32 0x62000000 - 0x6202d000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_extra.m32 0x65000000 - 0x6501a000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_net.m32 0x63000000 - 0x630a6000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_fragments.m32 0x75e10000 - 0x75eb0000 C:\Windows\system32\ADVAPI32.dll 0x775c0000 - 0x7766c000 C:\Windows\system32\msvcrt.dll 0x75d50000 - 0x75d69000 C:\Windows\SYSTEM32\sechost.dll 0x77670000 - 0x77711000 C:\Windows\system32\RPCRT4.dll 0x76f00000 - 0x76fc9000 C:\Windows\system32\USER32.dll 0x77a50000 - 0x77a9e000 C:\Windows\system32\GDI32.dll 0x77a30000 - 0x77a3a000 C:\Windows\system32\LPK.dll 0x75d70000 - 0x75e0d000 C:\Windows\system32\USP10.dll 0x74830000 - 0x749ce000 C:\Windows\WinSxS\x86_microsoft.windows.common-controls_6595b64144ccf1df_6.0.7600.16661_none_420fe3fa2b8113bd\COMCTL32.dll 0x772f0000 - 0x77347000 C:\Windows\system32\SHLWAPI.dll 0x775a0000 - 0x775bf000 C:\Windows\system32\IMM32.DLL 0x75eb0000 - 0x75f7c000 C:\Windows\system32\MSCTF.dll 0x72740000 - 0x727fe000 C:\Program Files\Java\jdk1.7.0\jre\bin\msvcr100.dll 0x01b80000 - 0x01e89000 C:\Program Files\Java\jdk1.7.0\jre\bin\client\jvm.dll 0x746c0000 - 0x746f2000 C:\Windows\system32\WINMM.dll 0x73920000 - 0x7392c000 C:\Program Files\Java\jdk1.7.0\jre\bin\verify.dll 0x73330000 - 0x73350000 C:\Program Files\Java\jdk1.7.0\jre\bin\java.dll 0x75d40000 - 0x75d45000 C:\Windows\system32\PSAPI.DLL 0x733a0000 - 0x733b3000 C:\Program Files\Java\jdk1.7.0\jre\bin\zip.dll 0x10000000 - 0x10259000 C:\Windows\System32\libspotify.dll 0x77150000 - 0x77185000 C:\Windows\system32\WS2_32.dll 0x77a40000 - 0x77a46000 C:\Windows\system32\NSI.dll 0x75ba0000 - 0x75cbc000 C:\Windows\system32\CRYPT32.dll 0x75ab0000 - 0x75abc000 C:\Windows\system32\MSASN1.dll 0x74ee0000 - 0x74f38000 C:\Windows\system32\WINHTTP.dll 0x74e90000 - 0x74edf000 C:\Windows\system32\webio.dll 0x754c0000 - 0x754d6000 C:\Windows\system32\CRYPTSP.dll 0x75260000 - 0x7529b000 C:\Windows\system32\rsaenh.dll 0x750a0000 - 0x750b7000 C:\Windows\system32\USERENV.dll 0x75a40000 - 0x75a4b000 C:\Windows\system32\profapi.dll 0x75a30000 - 0x75a3c000 C:\Windows\system32\CRYPTBASE.dll 0x728a0000 - 0x728b6000 C:\Program Files\Java\jdk1.7.0\jre\bin\net.dll 0x75480000 - 0x754bc000 C:\Windows\system32\mswsock.dll 0x75470000 - 0x75476000 C:\Windows\System32\wship6.dll 0x73950000 - 0x73960000 C:\Windows\system32\NLAapi.dll 0x75340000 - 0x75384000 C:\Windows\system32\DNSAPI.dll 0x71030000 - 0x71038000 C:\Windows\System32\winrnr.dll 0x71020000 - 0x71030000 C:\Windows\system32\napinsp.dll 0x71000000 - 0x71012000 C:\Windows\system32\pnrpnsp.dll 0x74fd0000 - 0x74fd5000 C:\Windows\System32\wshtcpip.dll 0x74d30000 - 0x74d4c000 C:\Windows\system32\IPHLPAPI.DLL 0x74d20000 - 0x74d27000 C:\Windows\system32\WINNSI.DLL 0x70c60000 - 0x70c66000 C:\Windows\system32\rasadhlp.dll 0x71ba0000 - 0x71bd8000 C:\Windows\System32\fwpuclnt.dll 0x73930000 - 0x7393f000 C:\Program Files\Java\jdk1.7.0\jre\bin\nio.dll 0x04990000 - 0x049e5000 C:\Users\nbarraille\AppData\Local\Temp\jna3666290841889849729.dll VM Arguments: jvm_args: -Djava.library.path=C:\Windows\System32 -Dfile.encoding=Cp1252 java_command: com.nbarraille.jspotify.main.Test Launcher Type: SUN_STANDARD Environment Variables: PATH=C:/Program Files/Java/jdk1.7.0/bin/../jre/bin/client;C:/Program Files/Java/jdk1.7.0/bin/../jre/bin;C:/Program Files/Java/jdk1.7.0/bin/../jre/lib/i386;C:\Windows\System32 USERNAME=nbarraille OS=Windows_NT PROCESSOR_IDENTIFIER=x86 Family 6 Model 23 Stepping 10, GenuineIntel --------------- SYSTEM --------------- OS: Windows 7 Build 7600 CPU:total 2 (2 cores per cpu, 1 threads per core) family 6 model 23 stepping 10, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1 Memory: 4k page, physical 3624108k(885020k free), swap 7246452k(3637664k free) vm_info: Java HotSpot(TM) Client VM (21.0-b01) for windows-x86 JRE (1.7.0-ea-b129), built on Feb 10 2011 07:43:39 by "java_re" with unknown MS VC++:1600 time: Mon Mar 07 14:25:08 2011 elapsed time: 0 seconds
编辑： * 在C *中测试API的代码
#include "api.h" /* --- Data --- */ const uint8_t g_appkey[] = {/*My appkey*/}; /* --------------------------- SESSION CALLBACKS ------------------------- */ static void logged_in(sp_session *sess, sp_error error){ printf("logged_in() called: \n"); } static void log_message(sp_session *sess, const char *data){ printf("log_message() called %s : \n", data); } static void notify_main_thread(sp_session *sess){ printf("notify_main_thread() called \n"); } static sp_session_callbacks session_callbacks = { //.logged_in = (void*)&logged_in, //.notify_main_thread = (void*)¬ify_main_thread, //.log_message = (void*)&log_message, }; static sp_session_config spconfig = { .api_version = 7, .cache_location = "tmp", .settings_location = "tmp", .application_key = g_appkey, .application_key_size = sizeof(g_appkey), .user_agent = "jspotify", .callbacks = &session_callbacks, .userdata = NULL }; int main(int argc, char **argv) { sp_session *sp; const char *username = "foo"; const char *password = "bar"; spconfig.application_key_size = sizeof(g_appkey); printf("Creating session \n"); sp_error err = sp_session_create(&spconfig, &sp); if(err != 0){ printf("Error occured: %d \n", err); return 0; } printf("Login\n"); sp_session_login(sp, username, password); Sleep(10000); return 0; }
当我像这样运行它（没有回调）时，输出是：
Creating session Login
当我注册回调（取消注释行）时，它甚至不打印任何东西！
看起来它在调用回调时没有打印任何东西，因为如果我注释sp_session_login行，只有notify_main_thread （这是唯一打印的）的声明将阻止程序打印…
当你有一个C结构，如：
struct Foo { Bar* bar }
即包含指向另一个结构的指针，你的JNA实现Bar（ class Bar extends Structure ）也必须实现Structure.ByReference接口 – 否则JNA会认为struct Foo包含struct Bar的实例而不是指向a的指针struct Bar ，并且将导致非法的内存访问，因为C代码将Bar实例中的值解释为指针。
您需要将implements Structure.ByReference添加到sp_session_callbacks类。
感谢鼓励我看看JNA – 这很酷！
此代码的输出是：
sp_session_create returned 0 sp_session_login returned 0 log_message() called:14:16:53.825 I [ap:1388] Connecting to AP ap.spotify.com:4070 log_message() called:14:16:54.061 I [ap:938] Connected to AP: 193.182.8.11:4070 log_message() called:14:16:54.765 E [ap:3396] Connection error: 401
进程以退出代码0结束
import com.sun.jna.*; import com.sun.jna.ptr.PointerByReference; import java.sql.Connection; public class JNATest { // static { // System.loadLibrary("libspotify"); // } public interface JLibspotify extends Library { int sp_session_create(sp_session_config config, PointerByReference sess); int sp_session_login(sp_session session, String username, String password); // All the other methods defined by the API } public static class sp_session extends PointerType { public sp_session(Pointer address) { super(address); } public sp_session() { super(); } } public static class sp_session_config extends Structure { public int api_version = 7; // The version of the Spotify API your application is compiled with. public String cache_location = "."; public String settings_location = "."; public Pointer application_key; // Your application key. public int application_key_size; // The size of the application key in bytes public String user_agent = "jspotify"; public sp_session_callbacks callbacks; // Delivery callbacks for session events. NULL if not interested in any callbacks public Pointer userdata; // User supplied data for your application public boolean compress_playlists; public boolean dont_save_metadata_for_playlists; public boolean initially_unload_playlists; } public interface LoggedIn extends Callback { public void logged_in(sp_session session, int error); } public interface LoggedOut extends Callback { public void logged_out(sp_session session, int error); } public interface ConnectionError extends Callback { public void connection_error(sp_session session, int error); } public static class sp_session_callbacks extends Structure implements Structure.ByReference{ public LoggedIn logged_in; // Called when login has been processed and was successful public LoggedOut logged_out; // Called when logout has been processded. Either called explicitly if you initialize a logout operation, or implicitly if there is a permanent connection error. public Callback metadata_updated; // Called whenever metadata has been updated. If you have metadata cached outside of libspotify, you should purge your caches and fetch new versions. public ConnectionError connection_error; // Called when there is a connection error, and the library has problems reconnecting to the Spotify service. Could be called multiple times (as long as the problem is present) public Callback message_to_user; // Called when the acces point wants to display a message to the user. In the desktop client, these are shown in a blueish toolbar just below the search box. public Callback notify_main_thread; // Called when processing needs to take place on the main thread. You need to call sp_session_process_events() in the main thread to get libspotify to do more work. Failure to do so may cause request timeouts, or a lost connections. public Callback music_delivery; // Called when there is decompressed audio data available. public Callback play_token_lost; // Music has been paused because only one account may play music at the same time. public Callback log_message; // Logging callback public Callback end_of_track; // End of track. Called when the currently played track has reached its end. public Callback streaming_error; // Streaming error. Called when streaming cannot start or continue. public Callback userinfo_updated; // Called after user info (anything related to sp_user objects) have been updated. public Callback start_playback; // Called when audio playback should start. For this to work correctly the application must also implement get_audio_buffer_stats(). This function is called from an internal session thread - you need to have proper synchronization. This function must never block. public Callback stop_playback; // Called when audio playback should stop. For this to work correctly the application must also implement get_audio_buffer_stats(). This function is called from an internal session thread - you need to have proper synchronization. This function must never block. public Callback get_audio_buffer_stats; // Called to query application about its audio buffer. This function is called from an internal session thread - you need to have proper synchronization! This function must never block. } private static final char[] APP_KEY ={/* Appkey here**/; public static void main(String[] args) throws InterruptedException { JLibspotify lib = (JLibspotify) Native.loadLibrary("spotify", JLibspotify.class); sp_session_config cfg = new sp_session_config(); Pointer ptr = new Memory(APP_KEY.length); ptr.write(0, toBytes(APP_KEY), 0, APP_KEY.length); cfg.application_key = ptr; cfg.application_key_size = APP_KEY.length; sp_session_callbacks sessCallbacks = new sp_session_callbacks(); LoggedIn loggedInCallback = new LoggedIn() { public void logged_in(sp_session session, int error) { System.out.println("logged_in() called"); } }; ConnectionError connectionErrorCallback = new ConnectionError() { public void connection_error(sp_session session, int error) { System.out.println("connection_error() called"); } }; LoggedOut loggedOutCallback = new LoggedOut() { public void logged_out(sp_session session, int error) { System.out.println("logged_out() called"); } }; sessCallbacks.logged_in = loggedInCallback; sessCallbacks.connection_error = connectionErrorCallback; sessCallbacks.logged_out = loggedOutCallback; sessCallbacks.log_message = new Callback() { public void callback(sp_session session, String message) { System.out.println("log_message() called:" + message); } }; cfg.callbacks = sessCallbacks; PointerByReference sessionPbr = new PointerByReference(); int error_id = lib.sp_session_create(cfg, sessionPbr); // CRASHES HERE System.out.println("sp_session_create returned " + error_id); // sp_session mySession = new sp_session(sessionPbr.getValue()); error_id = lib.sp_session_login(mySession, "foo", "bar"); System.out.println("sp_session_login returned " + error_id); Thread.sleep(1000); } public static byte[] toBytes(char[] key){ byte[] b = new byte[key.length]; for(int i =0; i < key.length; i++){ if(key[i] > 127){ b[i] = (byte)(key[i] - 256); }else{ b[i] = (byte)key[i]; } } return b; } }
这是一个C程序，它执行相同的操作（回调较少 – 您需要添加更多）。 它适用于OS X，因此您可能需要更改#include 。 由于我无法在澳大利亚获得spotify，我无法测试它是否成功登录是否会回调，但日志回调是有效的。
#include #include void SP_CALLCONV log_message(sp_session *session, const char *data) { fprintf(stderr,"log_message: %s\n", data); fflush(stderr); } void SP_CALLCONV connection_error(sp_session *session, sp_error error) { fprintf(stderr,"connection_error: %d\n", error); fflush(stderr); } int main(int argc, char** argv) { static byte APP_KEY[] = { /*the API key */}; static sp_session_callbacks callbacks; callbacks.log_message = log_message; callbacks.connection_error = connection_error; static sp_session_config cfg; cfg.callbacks = &callbacks; cfg.api_version = 7; cfg.cache_location = "."; cfg.settings_location = "."; cfg.user_agent = "jspotify"; cfg.application_key = APP_KEY; cfg.application_key_size = sizeof(APP_KEY); sp_session* mySession; int code = sp_session_create(&cfg, &mySession); printf("sp_session_create returned %d\n", code); sp_session_login(mySession, "foo", "bar"); printf("sp_session_login returned %d\n", code); sleep(10); }
如果C程序调用Java版本没有的回调，那么使用jna可能有问题 – 如果没有，也许还有更多关于spotify以及何时调用回调的内容。 我同意文档似乎说成功的登录会调用回调，但也许他们已经过时了？