使用JNI在C缓冲区中写入OutputStream

public class NativeWriter {
    public native void writeToOutputStream(byte[] buffer, int length);
}

javah -jni NativeWriter

#include "NativeWriter.h"
#include <stdio.h>

JNIEXPORT void JNICALL Java_NativeWriter_writeToOutputStream(JNIEnv *env, jobject obj, jbyteArray buffer, jint length) {
    jbyte *cBuffer = (*env)->GetByteArrayElements(env, buffer, NULL);
    // 将cBuffer中的数据写入到OutputStream中
    // ...
    (*env)->ReleaseByteArrayElements(env, buffer, cBuffer, 0);
}

gcc -shared -o libnativewriter.so NativeWriter.c

public class Main {
    static {
        System.loadLibrary("nativewriter");
    }

    public static void main(String[] args) {
        NativeWriter writer = new NativeWriter();
        byte[] buffer = new byte[1024];
        int length = buffer.length;
        writer.writeToOutputStream(buffer, length);
    }
}