1.首先确定环境是否支持javac,我就遇到使用java有用，而使用javac和javap都没有用.那一般就是环境变量的问题；

已我为例：原来CLASSPATH和JAVA_HOME只是配置在我的用户变量里面，后面我拷贝一份到系统变量中就解决了问题(重启电脑了javah不生效,需要保存重新保存一次,以管理员身份运行CMD);

 2.进入项目根目录：

C:\WINDOWS\system32>e:

E:\>cd E:\c_demo\AS_Jni_Project\voicechange\src\main\java

3.开始生成.h

 这里有个  -encoding UTF-8 是解决中文问题的  没加这句换会报错

E:\c_demo\AS_Jni_Project\voicechange\src\main\java>javah -classpath . -jni -encoding UTF-8 com.jszy.voicechange.MainActivity

到此.com_jszy_voicechange_MainActivity.h 问价就生成在E:\c_demo\AS_Jni_Project\voicechange\src\main\java 这个目录中

 看我项目文件

 代码段：

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_jszy_voicechange_MainActivity */

#ifndef _Included_com_jszy_voicechange_MainActivity
#define _Included_com_jszy_voicechange_MainActivity
#ifdef __cplusplus
extern "C" {
#endif
#undef com_jszy_voicechange_MainActivity_MODE_NORMAL
#define com_jszy_voicechange_MainActivity_MODE_NORMAL 0L
#undef com_jszy_voicechange_MainActivity_MODE_LUOLI
#define com_jszy_voicechange_MainActivity_MODE_LUOLI 1L
#undef com_jszy_voicechange_MainActivity_MODE_DASHU
#define com_jszy_voicechange_MainActivity_MODE_DASHU 2L
#undef com_jszy_voicechange_MainActivity_MODE_JINGSONG
#define com_jszy_voicechange_MainActivity_MODE_JINGSONG 3L
#undef com_jszy_voicechange_MainActivity_MODE_GAOGUAI
#define com_jszy_voicechange_MainActivity_MODE_GAOGUAI 4L
#undef com_jszy_voicechange_MainActivity_MODE_KONGLING
#define com_jszy_voicechange_MainActivity_MODE_KONGLING 5L
/*
 * Class:     com_jszy_voicechange_MainActivity
 * Method:    voiceChangeNative
 * Signature: (ILjava/lang/String;)V
 */
JNIEXPORT void JNICALL Java_com_jszy_voicechange_MainActivity_voiceChangeNative
  (JNIEnv *, jobject, jint, jstring);

#ifdef __cplusplus
}
#endif
#endif

已经成功了！！！！