char类型与jstring类型的转换

[ichiko]

我有一个char *,现在想将其转换成jstring，请问应该怎样做呢？我对c不是很熟悉，请高手指！

[macrojj]

http://www.mscto.com/Javatec/01176202.html

[kostion]

string str(你的char*);

[ichiko]

TO:macrojj
我也是用这种方法做的，但是生成的so在java调用就会提示：
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0xb775b0c9, pid=21196, tid=3075554192
#
# JRE version: 6.0_14-b08
# Java VM: Java HotSpot(TM) Client VM (14.0-b16 mixed mode, sharing linux-x86 )
# Problematic frame:
# V [libjvm.so+0x2210c9]
#
# An error report file with more information is saved as:
# /home/user/桌面/program/ictest/hs_err_pid21196.log
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#
Java Result: 134

我的c++代码是这样的：

  #include<iostream>
  #include<dlfcn.h>
  #include<stdio.h>
  #include<stdlib.h>
  #include<string.h>
  #include "ictest.h"
  
  JNIEXPORT jint JNICALL Java_ictest_auto_1init
    (JNIEnv * env, jclass obj, jint a)
  {
  	void* handle = dlopen("/home/user/Linux/mwic.so",RTLD_LAZY);
  	typedef int (*auto_init)(char*,int);
  	dlerror();
  	auto_init AutoInit = (auto_init) dlsym(handle,"auto_init");
  	const char *dlsym_error = dlerror();
  	if(dlsym_error){
  		dlclose(handle);
  		return -1;
  	}
  	int i=AutoInit("/home/user/Linux/star500x",a);
  	return i;
  }
  
  
  JNIEXPORT jstring JNICALL Java_ictest_rsc_14442
    (JNIEnv * env, jclass obj, jint a, jint b)
  {
  	int step=0;
  	void * handle = dlopen("/home/user/Linux/mwic.so",RTLD_LAZY);
  	step++;
  	typedef int (*rsc_4442)(int,int,char*);
  	step++;
  	dlerror();
  	step++;
  	rsc_4442 Rsc4442 =(rsc_4442) dlsym(handle,"rsc_4442");
  	step++;
  	const char *dlsym_error = dlerror();
  	step++;
  	if(dlsym_error){
  	step++;
  		dlclose(handle);
  	step++;
  	}
  	char* password;
  	step++;
  	Rsc4442(a,b,password);
  	step++;
  	jstring jstr;
  	step++;
  	jstr = stoJstring(env,password);
  	step++;
  	return jstr;
  }
    jstring stoJstring(JNIEnv* env, const char* pat) 
    { 
           jclass strClass = env->FindClass("Ljava/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); 
    }

我的头文件是：

  /* DO NOT EDIT THIS FILE - it is machine generated */
  #include "jni.h"
  /* Header for class ictest */
  
  #ifndef _Included_ictest
  #define _Included_ictest
  #ifdef __cplusplus
  extern "C" {
  #endif
  /*
   * Class:     ictest
   * Method:    auto_init
   * Signature: (I)I
   */
  JNIEXPORT jint JNICALL Java_ictest_auto_1init
    (JNIEnv *, jclass, jint);
  
  /*
   * Class:     ictest
   * Method:    rsc_4442
   * Signature: (II)Ljava/lang/String;
   */
  JNIEXPORT jstring JNICALL Java_ictest_rsc_14442
    (JNIEnv *, jclass, jint, jint);
  
  
  jstring stoJstring(JNIEnv* , const char*);
  
  #ifdef __cplusplus
  }
  #endif
  #endif

并且在linux下用“ g++ -wl,--kill-at -shared -o ictest.so ictest.cpp”这个命令生成so文件，请问我那里不对了呢？谢谢解答！

[ichiko]

有人回复吗？这个问题比较急啊～～～

[darxin]

jstring toJstring(JNIEnv* env, const char* pat) { 
  jclass strClass = env->FindClass("Ljava/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); 
} 

[darxin]

参考一下brace的文章
关于SIGSEGV错误及处理方法

[zzzhktk]

JNIEXPORT jstring JNICALL Java_com_xmcx_yw_jni_BiosTableReader_getDeviceType
(JNIEnv *env, jobject jo)
{
char DevType[MINSIZE]="";

getDeviceType(DevType, &bios_table);

return (*env)->NewStringUTF(env, DevType);
}

我是这么做的，可以参考一下