Question

当前，我正在尝试在Raspberry Pi 3上使用蓝牙，在尝试使用其他未完成的库后，我选择了DBus（快照2.1.1）上的BlueCove，因为它似乎已经完成并且并没有强制使用GPL许可证。不幸的是，给定的编译库没有包含ARM的本机，因此经过反复试验，我编译了该API的本机及其先决条件。还是我想。

我在尝试使用API时收到UnsatisfiedLinkError。我可以确认该库正在加载到JVM中，并且在调用本机方法时出现错误。

java.lang.UnsatisfiedLinkError：com.intel.bluetooth.BluetoothStackBlueZDBus.getLibraryVersionNative（）I 在com.intel.bluetooth.BluetoothStackBlueZDBus.getLibraryVersionNative（本机方法）在com.intel.bluetooth.BluetoothStackBlueZDBus.getLibraryVersion（BluetoothStackBlueZDBus.java:160）在com.intel.bluetooth.BlueCoveImpl.detectStack（BlueCoveImpl.java:471）在com.intel.bluetooth.BlueCoveImpl.access上获得$ 500（BlueCoveImpl.java:69）在com.intel.bluetooth.BlueCoveImpl $ 1.run（BlueCoveImpl.java:1044）在java.base / java.security.AccessController.doPrivileged（本机方法）在com.intel.bluetooth.BlueCoveImpl.detectStackPrivileged（BlueCoveImpl.java:1042）在com.intel.bluetooth.BlueCoveImpl.getBluetoothStack（BlueCoveImpl.java:1035）在javax.bluetooth.LocalDevice.getLocalDeviceInstance（LocalDevice.java:75）在javax.bluetooth.LocalDevice.getLocalDevice（LocalDevice.java:95）在tech.delta.system_automation.server.bin.connections.bluetooth.RemoteDeviceDiscovery.discoverDevices（RemoteDeviceDiscovery.java:54）在tech.delta.system_automation.server.bin.Autonoma_Server.main（Autonoma_Server.java:40）

这是我初始化流程的地方

LocalDevice d = LocalDevice.getLocalDevice();

这是BlueCove API中Java代码失败的地方

private native int getLibraryVersionNative();

public int getLibraryVersion() throws BluetoothStateException {
    int version = getLibraryVersionNative();
    if (version != BLUECOVE_DBUS_VERSION) {
        DebugLog.fatal("BlueCove native library version mismatch " + version + " expected " + BLUECOVE_DBUS_VERSION);
        throw new BluetoothStateException("BlueCove native library version mismatch");
    }
    return version;
}

这是它试图使用的C代码

JNIEXPORT jint JNICALL Java_com_intel_bluetooth_BluetoothStackBlueZDBus_getLibraryVersionNative
(JNIEnv *env, jobject peer) {
    return com_intel_bluetooth_BluetoothStackBlueZDBus_BLUECOVE_DBUS_VERSION;
}

现在，我只能假设该代码在带有预编译本机的x86 / 64系统上使用时可以运行，但是我运气不佳，老实说，我没有使用JNI和C语言的经验知识有限，我一生中都没有写过Makefile。但是我怀疑这可能是C方面的链接问题。

我正在考虑在编译C代码时出现标志问题，该代码拒绝使用其编译的jar。我怀疑是因为必须将lib文件从libbluecovez.so重命名为libbluecovez_arm.so。但是我不确定，我正在寻找一些经验丰富的用户，这些用户可能会指出正确的方向。

以下是供参考的Makefile

# @version $Revision: 2829 $ ($Author: skarzhevskyy $) $Date: 2009-03-03 03:44:45 -0500 (Tue, 03 Mar 2009) $
#
# Created by Francois Kooman
#
# Use this file in case you don't have ant or maven installed on the system
# Usage: make all
#

BLUECOVE_VERSION=2.1.1-SNAPSHOT

BLUECOVE_JAR=../bluecove/target/bluecove-${BLUECOVE_VERSION}.jar
JAVAH=$(JAVA_HOME)/bin/javah
JAVAC=$(JAVA_HOME)/bin/javac
JAVAC_OPTIONS=-g -source 1.5 -target 1.5
CC=gcc
CFLAGS=-Wall -fPIC -fno-stack-protector # -Werror
# -nodefaultlibs ->  statically linked
CLIBFLAGS=$(CFLAGS) -nodefaultlibs -shared -Wl,-soname,libbluecovez-$(BLUECOVE_VERSION)
SRC_C_DIR=src/main/c
SRC_JAVA_DIR=src/main/java
CLASSES_DIR=target/classes
OBJ_DIR=target/native
JAVACLASSES=com.intel.bluetooth.BluetoothStackBlueZDBus com.intel.bluetooth.BluetoothStackBlueZDBusConsts com.intel.bluetooth.BluetoothStackBlueZDBusNativeTests org.bluecove.socket.LocalSocketImpl
LIBPOSTFIX=`uname -p | grep 64 | sed 's/.*64.*/_x64/g'`

TARGET_LIB=target/libbluecovez$(LIBPOSTFIX).so

DBUS_JAVA_LIBS_DIR=target
DBUS_JAVA_CLASSPATH=$(DBUS_JAVA_LIBS_DIR)/dbus.jar:$(DBUS_JAVA_LIBS_DIR)/unixsockets.jar
CLASSPATH=$(BLUECOVE_JAR):$(DBUS_JAVA_CLASSPATH)

all: classes jni-headers native-lib

classes:
    -@mkdir -p $(CLASSES_DIR)
    -@$(JAVAC) -d $(CLASSES_DIR) $(JAVAC_OPTIONS) -classpath $(CLASSPATH) \
    $(SRC_JAVA_DIR)/org/bluez/*.java $(SRC_JAVA_DIR)/com/intel/bluetooth/*.java $(SRC_JAVA_DIR)/org/bluecove/socket/*.java

jni-headers:
    -@$(JAVAH) -d $(SRC_C_DIR) \
    -classpath $(CLASSPATH):$(CLASSES_DIR) \
    $(JAVACLASSES)

native-lib:
    -@mkdir -p $(OBJ_DIR)
    -@cd $(OBJ_DIR) && \
    $(CC) $(CFLAGS) -c ../../$(SRC_C_DIR)/*.c -I${JAVA_HOME}/include -I${JAVA_HOME}/include/linux
    -@$(CC) $(CLIBFLAGS) -o $(TARGET_LIB) $(OBJ_DIR)/*.o
    -@strip $(TARGET_LIB)
    -@cp $(TARGET_LIB) $(CLASSES_DIR)/libbluecovez$(LIBPOSTFIX).so
    -@echo "Native library $(TARGET_LIB) created"
    -@echo "Shared library dependencies:"
    -@ldd -v $(TARGET_LIB)

clean:
    rm -rf target

我怀疑Makefile中的行是

CLIBFLAGS=$(CFLAGS) -nodefaultlibs -shared -Wl,-soname,libbluecovez-$(BLUECOVE_VERSION)

和

TARGET_LIB=target/libbluecovez$(LIBPOSTFIX).so

考虑到最终的jar称为bluecove-bluez-2.1.1-SNAPSHOT.jar，而lib文件称为libbluecovez_arm.so

如果有人可以给我一些帮助，那就太好了。

更新，所以问题出在我的Makefile上，导致Javah出现问题，而Javah又导致C编译器出现问题，并且是我问题的根源。

这是编译错误

Error: Could not find class file for 'com.intel.bluetooth.BluetoothStackBlueZDBus'.
Error: Could not find class file for 'com.intel.bluetooth.BluetoothStackBlueZDBusConsts'.
Error: Could not find class file for 'com.intel.bluetooth.BluetoothStackBlueZDBusNativeTests'.
Error: Could not find class file for 'org.bluecove.socket.LocalSocketImpl'.
Makefile:40: recipe for target 'jni-headers' failed
make: [jni-headers] Error 1 (ignored)
In file included from ../../src/main/c/BlueCoveBlueZ.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveBlueZ_L2CAP.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveBlueZ_L2CAPServer.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveBlueZ_RFCOMM.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveBlueZ_RFCOMMServer.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveBlueZ_Tests.c:26:0:
../../src/main/c/BlueCoveBlueZ.h:38:57: fatal error: com_intel_bluetooth_BluetoothStackBlueZDBus.h: No such file or di            rectory
 #include "com_intel_bluetooth_BluetoothStackBlueZDBus.h"
                                                         ^
compilation terminated.
In file included from ../../src/main/c/BlueCoveLocalSocket.c:27:0:
../../src/main/c/BlueCoveLocalSocket.h:40:49: fatal error: org_bluecove_socket_LocalSocketImpl.h: No such file or dire            ctory
 #include "org_bluecove_socket_LocalSocketImpl.h"
                                                 ^
compilation terminated.

因此，我需要修改Makefile，使其正确指向.java文件？我不确定。

Answer 1

对于其他遇到相同问题的人。由于某种原因，原始的make文件在项目布局中无法与现代Java一起使用。这将导致编译错误，导致无法生成.class文件。反过来，这意味着Javah（从Java 10开始不推荐使用）在尝试生成供本机库通过JNI进行通信的头文件时失败。 c编译器会忽略缺少头文件的情况，因此仍会进行编译。这导致了通用链接器错误。该文件在那里，但编译时未包含Java头文件。

要解决此问题，我在Windows系统上编译了jar罐Bluecove-bluez，从make文件中删除了编译类，同时清理了目标，然后将类从Windows系统直接复制到了目标，并将其复制到了我当时使用的闪存驱动器中。编译。将闪存驱动器移至ARM Linux系统，仅编译头文件以及c natives即可解决此问题。

在ARM上使用BlueCove-DBus。 Linux上C库和Java代码（JNI）之间的链接器错误

1 个答案: