利用JNA使Java訪問本地C++
阿新 • • 發佈:2019-02-11
(1)C++程式碼
typedef int (*CB_OnServiceUserMessage)(uint32_t cid, uint32_t uid, const std::string& data); extern "C" { void init(CB_OnMsg cb_OnMsg) { (*cb_OnMsg)(); std::cout << "Initializing..." << std::endl; } void start() { std::cout << "Start up!" << std::endl; } void stop() { std::cout << "Shut down!" << std::endl; } void send(char* msg) { std::cout << msg << std::endl; } }
(2)Java程式碼
PluginProxy.java
import java.io.IOException; import java.lang.management.ManagementFactory; import com.sun.jna.Callback; import com.sun.jna.Library; import com.sun.jna.Native; public class PluginProxy { private static String libPath; private interface LibPluginProxy extends Library { static LibPluginProxy INSTANCE = (LibPluginProxy) Native.loadLibrary(libPath, LibPluginProxy.class); public void init(Callback callback); public void start(); public void stop(); public void send(String msg); } public static void main(String[] args) throws Exception { libPath = "libPluginProxy.so"; LibPluginProxy.INSTANCE.init(new CB_OnMsg()); System.out.println("in main function."); //add shutdown hook Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() { @Override public void run() { Native.unregister(LibPluginProxy.class); System.out.println("stop.."); LibPluginProxy.INSTANCE.stop(); String n = ManagementFactory.getRuntimeMXBean().getName(); if (n == null) return; String pid = n.substring(0, n.indexOf("@")); if (pid == null) return; try { Runtime.getRuntime().exec("kill -9 " + pid); } catch (IOException e) { e.printStackTrace(); } System.exit(-1); } })); Thread t = new Thread(new Runnable() { @Override public void run() { LibPluginProxy.INSTANCE.start(); System.out.println("started in thread.."); } }); t.start(); System.out.println("started!!"); } }
CB_OnMsg.java
import com.sun.jna.Callback;
public class CB_OnMsg implements Callback {
// 應用建立
public final int onMsg() {
System.out.println("CB_OnMsg, in function onMsg.");
return 0;
}
}
(3)編譯C++的.so共享庫
編寫makefile,細節忽略,只提供最主要的command,如下:
g++ -shared -o libplugin.so -fPIC -Wall -ggdb -D_REENTRANT -DHAVE_EPOLL -DXML_NULL -DSTATUS_NEWPROTOCOL -Wl,-rpath,../bin #注:此段有多餘的flags,有待修改...
(4)生成Java的JAR包
在eclipse中生成JAR包,linux生成JAR命令請Google......
(5)執行JAR包呼叫.so共享庫
在linux下輸入命令:
java -cp jna-3.3.0.jar:ss.jar PluginProxy