JNI的使用

1. 源文件：

   public class Info {
   
           public String Name;
   	
           public String Time;
   }

   public class Action {
   
   	public native byte[] genReq(int hash_algorithm, byte[] data);
   
   	public native boolean verifyRes(int hash_algorithm, byte[] resp);
   
   	public native Info getInfo(byte[] resp);
   
   
   	public static Action getInstance() {
   		System.loadLibrary("the_dll");
   		Action a = new Action();
   
   		return a;
   	}
   }

    

2. 頭文件：

   /* DO NOT EDIT THIS FILE - it is machine generated */
   #include <jni.h>
   /* Header for class Action */
   
   #ifndef _Included_Action
   #define _Included_Action
   #ifdef __cplusplus
   extern "C" {
   #endif
   /*
    * Class:     Action
    * Method:    genReq
    * Signature: (I)[B
    */
   JNIEXPORT jbyteArray JNICALL Java_Action_genReq
     (JNIEnv *, jobject, jint);
   
   /*
    * Class:     Action
    * Method:    verifyRes
    * Signature: (I[B)Z
    */
   JNIEXPORT jboolean JNICALL Java_Action_verifyRes
     (JNIEnv *, jobject, jint, jbyteArray);
   
   /*
    * Class:     Action
    * Method:    getInfo
    * Signature: ([B)LInfo;
    */
   JNIEXPORT jobject JNICALL Java_Action_getInfo
     (JNIEnv *, jobject, jbyteArray);
   
   #ifdef __cplusplus
   }
   #endif
   #endif
   

    

3. C++文件：

   #include "Action.h"
   #include "jni.h"
   #include <stdio.h>
   #include <stdlib.h>
   #include <string.h> 
   
   JNIEXPORT jbyteArray JNICALL Java_Action_genReq
   	(JNIEnv * env, jobject obj, jint hash_algorithm, jbyteArray data)
   {
   	jbyteArray result= NULL;
   
   	void *TS_handle;
   	int error_code;
   	unsigned char *request;
   	unsigned int request_len;
   
   	unsigned char* raw_data = (unsigned char*)env->GetByteArrayElements(data, 0);
   	unsigned int raw_data_len =env->GetArrayLength(data);
   
   	......
   	
   	if ( !( request = (unsigned char *)malloc(request_len) ) )
   	{
   	    ......
   	}
   
       ......
   
   	result = env->NewByteArray(request_len);
   	env->SetByteArrayRegion(result,0, request_len, (jbyte*)request);
   
   	......
   	
   	return result;
   }
   
   JNIEXPORT jboolean JNICALL Java_Action_verifyRes
   	(JNIEnv * env, jobject obj, jint hash_algorithm, jbyteArray resp)
   {
   	jboolean result = 0;
   
   	void *TS_handle;
   	int error_code;
   	unsigned int status_code, info_code_flag, info_code;
   
   	......
   
   	unsigned char* response_ASN1_encode = (unsigned char*)env->GetByteArrayElements(resp, 0);
   	unsigned int response_ASN1_encode_len =env->GetArrayLength(resp);
   
   	......
   
   	result = 1;
   
   	......
   
   	return result;
   }
   
   JNIEXPORT jobject JNICALL Java_Action_getInfo
   	(JNIEnv * env, jobject obj, jbyteArray resp)
   {
   	jobject result= NULL;
   
   	jclass info = env->FindClass("the/path/Info");
   	jobject ainfo = env->AllocObject(info);
   
   	void *A_handle;
   	int error_code;
   	unsigned int name_len, time_len;
   	unsigned char *name, *time;
   
   	......
   
   	unsigned char* response_ASN1_encode = (unsigned char*)env->GetByteArrayElements(resp, 0);
   	unsigned int response_ASN1_encode_len =env->GetArrayLength(resp);
   
   	......
   
   	if (name_len)
   	{
   		if ( !(name=(unsigned char *)malloc(name_len)) )
   		{
   		    ......
   		}
   
   	    ......
   
   		jclass strClass = env->FindClass("Ljava/lang/String;");
   		jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([B)V");
   		jbyteArray bytes = env->NewByteArray(name_len);
   		env->SetByteArrayRegion(bytes, 0, name_len, (jbyte*)name);
   		jstring encoding = env->NewStringUTF("utf-8");
   		jobject str = env->NewObject(strClass, ctorID, bytes, encoding);
   		jfieldID fld_name = env->GetFieldID(info, "Name", "Ljava/lang/String;");
   		env->SetObjectField(info, fld_name, str);
   
   		free(name);
   	}
   	else{
   	}
   
   	if (time_len)
   	{
   		if ( !(time=(unsigned char *)malloc(time_len)) )
   		{
   		    ......
   		}
   
   	    ......
   
   		jclass strClass = env->FindClass("Ljava/lang/String;");
   		jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([B)V");
   		jbyteArray bytes = env->NewByteArray(time_len);
   		env->SetByteArrayRegion(bytes, 0, time_len, (jbyte*)time);
   		jstring encoding = env->NewStringUTF("utf-8");
   		jobject str = env->NewObject(strClass, ctorID, bytes, encoding);
   		jfieldID fld_time = env->GetFieldID(info, "Time", "Ljava/lang/String;");
   		env->SetObjectField(info, fld_time, str);
   
   		free(time);
   	}
   	else{
   	}
   
   	result = info;
   
   	......
   
   	return result;
   }

    

4. 調用方式：

   ......
   
   Action a = Action.getInstance();
   
   req = a.genReq(hash_algorithm, input.getBytes("utf-8"));
   
   boolean isOK = a.verifyRes(hash_algorithm, resp);
   
   Info Info = a.getInfo(resp);
   
   ......