JNI With Strings

StringJNICaller.java

   1 class StringJNICaller{
   2         public native String getUppercaseString(String inpStr);
   3         
   4         public static void main(String args[]){
   5                 System.loadLibrary("stringlib");
   6                 
   7                 StringJNICaller sjnic=new StringJNICaller();
   8                 String uprstr=sjnic.getUppercaseString("hello sri lanka");
   9                 System.out.println(uprstr);
  10         }
  11 }

StringJNICaller.h

   1 /* DO NOT EDIT THIS FILE - it is machine generated */
   2 #include <jni.h>
   3 /* Header for class StringJNICaller */
   4 
   5 #ifndef _Included_StringJNICaller
   6 #define _Included_StringJNICaller
   7 #ifdef __cplusplus
   8 extern "C" {
   9 #endif
  10 /*
  11  * Class:     StringJNICaller
  12  * Method:    getUppercaseString
  13  * Signature: (Ljava/lang/String;)Ljava/lang/String;
  14  */
  15 JNIEXPORT jstring JNICALL Java_StringJNICaller_getUppercaseString
  16   (JNIEnv *, jobject, jstring);
  17 
  18 #ifdef __cplusplus
  19 }
  20 #endif
  21 #endif

StringJNICaller.cpp

   1 #include "StringJNICaller.h"
   2 #include <string.h>
   3 
   4 JNIEXPORT jstring JNICALL Java_StringJNICaller_getUppercaseString(JNIEnv *env, jobject obj, jstring string)
   5 {
   6         const char *str=env->GetStringUTFChars(string,0);
   7         char cap[128];
   8         strcpy(cap,str);
   9         env->ReleaseStringUTFChars(string,str);
  10         return env->NewStringUTF(strupr(cap));
  11 }
  12 

Download Source Codes

References :
[1] http://www.ibm.com/developerworks/java/tutorials/j-jni/section2.html