我目前正在构建一个Spring Boot应用程序，我想通过IMAP上的聊天发送一些邮件。Deltachat实现了COI。DeltaChat提供了一个用RUST编写的API。https://github.com/deltachat/deltachat-core-rust
如此处所示https://support.delta.chat/t/bindings-for-java/970
Java绑定应由Android应用程序https://github.com/deltachat/deltachat-android/tree/master/src/com/b44t/messenger实现
另外，我需要启动JNI：https://github.com/deltachat/deltachat-android/tree/master/jni
我把jni和messenger这两个文件夹和deltachat-core-rust Projekt一起复制到了一个单独的java项目中。但是，我不知道如何将Java类连接到C代码中。最好的方法是什么？在JNI文件夹中仍然有www.example.com类，我必须自己实现那里实现的内容吗？Android.mk class, do I have to implement what is implemented there myself?
更新：
现在我已经使用以下代码创建了共享库：

cmake_minimum_required(VERSION 3.16)
project(deltachat LANGUAGES C)
find_package(JNI REQUIRED)

# generate libnative.jnilib
include_directories(${JNI_INCLUDE_DIRS} )

add_library(native MODULE dc_wrapper.c ${CMAKE_CURRENT_SOURCE_DIR}/deltachat-core-rust/deltachat-ffi/deltachat.h)
#set_target_properties(native PROPERTIES SUFFIX ".jnilib")
target_link_libraries(native ${JNI_LIBRARIES} )
target_link_libraries(native ${CMAKE_CURRENT_SOURCE_DIR}/deltachat-core-rust/target/release/libdeltachat.a)

是这样吗？
当我尝试运行这个：

import messenger.DcContext;

public class MainJni {

    static {
        System.loadLibrary("native");
    }

    public static void main(String[] args) {
        DcContext dcContext = new DcContext("ubuntu", "example.db");

        if(dcContext == null){

        }
    }

}

我得到这个错误

Exception in thread "main" java.lang.UnsatisfiedLinkError: /home/robin/Documents/DeltaChatCoreJavaBindings/src/jni/build/libnative.so: /home/robin/Documents/DeltaChatCoreJavaBindings/src/jni/build/libnative.so: undefined symbol: SSL_get_error
    at java.base/java.lang.ClassLoader$NativeLibrary.load0(Native Method)
    at java.base/java.lang.ClassLoader$NativeLibrary.load(ClassLoader.java:2442)
    at java.base/java.lang.ClassLoader$NativeLibrary.loadLibrary(ClassLoader.java:2498)
    at java.base/java.lang.ClassLoader.loadLibrary0(ClassLoader.java:2694)
    at java.base/java.lang.ClassLoader.loadLibrary(ClassLoader.java:2659)
    at java.base/java.lang.Runtime.loadLibrary0(Runtime.java:830)
    at java.base/java.lang.System.loadLibrary(System.java:1873)
    at MainJni.<clinit>(MainJni.java:6)

有什么建议吗？