Java JNI使用之将JAVA的 String[ ] 字符串数组转化成C语言的 char

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:
   
/* 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：
   
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）：

    
/*
 * 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         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。