jstring 和char* 之间的转换方法

待我称王封你为后i 2022-06-18 09:56 541阅读 0赞

原文：[http://qdjinxin.iteye.com/blog/390973][http_qdjinxin.iteye.com_blog_390973]

//jstring to char* 
    char* jstringTostring(JNIEnv* env, jstring jstr) 
    { 
           char* rtn = NULL; 
           jclass clsstring = env->FindClass("java/lang/String"); 
           jstring strencode = env->NewStringUTF("utf-8"); 
           jmethodID mid = env->GetMethodID(clsstring, "getBytes", "(Ljava/lang/String;)[B"); 
           jbyteArray barr= (jbyteArray)env->CallObjectMethod(jstr, mid, strencode); 
           jsize alen = env->GetArrayLength(barr); 
           jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE); 
           if (alen > 0) 
           { 
                     rtn = (char*)malloc(alen + 1); 
                     memcpy(rtn, ba, alen); 
                     rtn[alen] = 0; 
           } 
           env->ReleaseByteArrayElements(barr, ba, 0); 
           return rtn; 
    } 
    //char* to jstring 
    jstring stoJstring(JNIEnv* env, const char* pat) 
    { 
           //jclass strClass = env->FindClass("Ljava/lang/String;"); 
           jclass strClass = env->FindClass("java/lang/String"); 
           jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([BLjava/lang/String;)V"); 
           jbyteArray bytes = env->NewByteArray(strlen(pat)); 
           env->SetByteArrayRegion(bytes, 0, strlen(pat), (jbyte*)pat); 
           jstring encoding = env->NewStringUTF("utf-8"); 
           return (jstring)env->NewObject(strClass, ctorID, bytes, encoding); 
    }

**注：**

如果是c程序，要用 (\*env)->

如果是C++要用 env->

**例如：**

C++中使用  
env->FindClass("java/lang/String")

C中使用

(\*env)->FindClass(env, "java/lang/String")

[http_qdjinxin.iteye.com_blog_390973]: http://qdjinxin.iteye.com/blog/390973