更新时间:2022-09-08 15:48:55
用java直接调用c里面的main(int argc,*char[] argv),那么在java层面上,就需要使用String[]字符串数组,然后将String[]转化成C语言的char**。
根据前面的文章,制作调用JNI的C头文件:
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/* DO NOT EDIT THIS FILE - it is machine generated */ #include "jni.h" /* Header for class com_xmu_engine_HTK */ #ifndef _Included_com_xmu_engine_HTK #define _Included_com_xmu_engine_HTK #ifdef __cplusplus extern "C" {
#endif /* * Class: com_xmu_engine_HTK
* Method: HCopy
* Signature: ([Ljava/lang/String;)[Ljava/lang/String;
*/
JNIEXPORT jobjectArray JNICALL Java_com_xmu_engine_HTK_HCopy (JNIEnv *, jclass, jobjectArray);
/* * Class: com_xmu_engine_HTK
* Method: HVite
* Signature: ([Ljava/lang/String;)V
*/
JNIEXPORT void JNICALL Java_com_xmu_engine_HTK_HVite
(JNIEnv *, jclass, jobjectArray);
/* * Class: com_xmu_engine_HTK
* Method: HParse
* Signature: ([Ljava/lang/String;)V
*/
JNIEXPORT void JNICALL Java_com_xmu_engine_HTK_HParse
(JNIEnv *, jclass, jobjectArray);
#ifdef __cplusplus } #endif #endif |
我们看到,jobjectArray就是C的jni定义的String字符串数组。这三个函数在java中的声明:
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package com.xmu.engine;
public class HTK {
public static native void HCopy(String args[]);
public static native void HVite(String args[]);
public static native void HParse(String args[]);
static {
System.loadLibrary( "htkengine" );
}
} |
下面,重点来看看怎样将JAVA String[]转化按成C的char**(看其中的HVite如何实现,其余两个类似):
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/* * Class: com_xmu_engine_HTK
* Method: HVite
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_xmu_engine_HTK_HVite
(JNIEnv * env, jclass jc,jobjectArray strArray ){
jstring jstr;
jsize len = (*env)->GetArrayLength(env, strArray);
char **pstr = ( char **) malloc (len* sizeof ( char *));
int i=0;
for (i=0 ; i<len; i++) {
jstr = (*env)->GetObjectArrayElement(env, strArray, i);
pstr[i] = ( char *)(*env)->GetStringUTFChars(env, jstr, 0);
}
HVite(len,pstr);
} |
代码应该很清楚,不再详细解释了。