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POJNI in C++ to read file to jbyteArray
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copied!<p>I am writing a C++ program in UNIX to generate a shared library which will be called in java using JNI. This C++ program has to read a file in UNIX box then it will have to be converted into <code>jbyteArray</code> (JNI data type) so that JAVA can use it. </p> <p>I read the file in C++ into <code>char*</code> but could not convert into <code>jbyteArray</code>. Please help it.</p> <p>Code is below::</p> <pre><code>#include <iostream> #include <fstream> #include <stdio.h> #include "com_sp_dll_NativeMethods.h" // this header file was generated by java using namespace std; JNIEXPORT void JNICALL Java_HelloWorld_displayMessage(JNIEnv *env, jobject obj) { printf("Hello World!\n"); } JNIEXPORT jbyteArray JNICALL Java_com_sp_dll_NativeMethods_getFile(JNIEnv *env, jobject obj) { ifstream fl("/home/rkannan/myFile.txt"); fl.seekg(0, ios::end ); size_t len = fl.tellg(); char *ret = new char[len]; fl.seekg(0, ios::beg); fl.read(ret, len); fl.close(); int i = 0; jbyte *a1 = null; while(ret[i] != '\0'){ cout<<ret[i]; al[i] = ret[i]; i++; } jbyteArray result = env->NewByteArray( len); env->SetByteArrayRegion( result, 0, len, (const jbyte*) ret ); delete[] ret; return result; } </code></pre> <p>The error is as follows</p> <pre><code>bash-3.00$ g++ -I /usr/jdk/instances/jdk1.5.0/include -I /usr/jdk/instances/jdk1.5.0/include/solaris -o libSample.so -shared com_sp_dll_NativeMethods.cpp Text relocation remains referenced against symbol offset in file std::__ioinit 0x550 /var/tmp//ccKCiEKq.o std::__ioinit 0x554 /var/tmp//ccKCiEKq.o std::__ioinit 0x588 /var/tmp//ccKCiEKq.o std::__ioinit 0x58c /var/tmp//ccKCiEKq.o .rodata (section) 0x204 /var/tmp//ccKCiEKq.o .rodata (section) 0x208 /var/tmp//ccKCiEKq.o .rodata (section) 0x244 /var/tmp//ccKCiEKq.o .rodata (section) 0x248 /var/tmp//ccKCiEKq.o .rodata (section) 0x2f4 /var/tmp//ccKCiEKq.o .rodata (section) 0x2f8 /var/tmp//ccKCiEKq.o std::fpos<__mbstate_t>::operator long long() const0x348 /var/tmp//ccKCiEKq.o std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char)0x400 /var/tmp//ccKCiEKq.o std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)0x2cc /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::is_open()0x260 /var/tmp//ccKCiEKq.o std::basic_istream<char, std::char_traits<char> >::read(char*, int)0x39c /var/tmp//ccKCiEKq.o JNIEnv_::SetByteArrayRegion(_jbyteArray*, int, int, signed char const*)0x468 /var/tmp//ccKCiEKq.o operator new[](unsigned int) 0x364 /var/tmp//ccKCiEKq.o std::basic_istream<char, std::char_traits<char> >::seekg(long long, std::_Ios_Seekdir)0x31c /var/tmp//ccKCiEKq.o std::basic_istream<char, std::char_traits<char> >::seekg(long long, std::_Ios_Seekdir)0x384 /var/tmp//ccKCiEKq.o std::basic_istream<char, std::char_traits<char> >& std::operator>><char, std::char_traits<char> >(std::basic_istream<char, std::char_traits<char> >&, char*)0x2b4 /var/tmp//ccKCiEKq.o printf 0x20c /var/tmp//ccKCiEKq.o JNIEnv_::NewByteArray(int) 0x444 /var/tmp//ccKCiEKq.o std::ios_base::Init::Init() 0x558 /var/tmp//ccKCiEKq.o std::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const0x14 /var/tmp//ccKCiEKq.o std::cout 0x2c0 /var/tmp//ccKCiEKq.o std::cout 0x2c4 /var/tmp//ccKCiEKq.o std::cout 0x3f4 /var/tmp//ccKCiEKq.o std::cout 0x3f8 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream()0x234 /var/tmp//ccKCiEKq.o std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned int) const0x9c /var/tmp//ccKCiEKq.o std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned int) const0x128 /var/tmp//ccKCiEKq.o std::basic_string<char, std::char_traits<char>, std::allocator<char> >::operator[](unsigned int) const0x184 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::open(char const*, std::_Ios_Openmode)0x250 /var/tmp//ccKCiEKq.o std::ios_base::Init::~Init() 0x590 /var/tmp//ccKCiEKq.o std::basic_ios<char, std::char_traits<char> >::eof() const0x288 /var/tmp//ccKCiEKq.o unsigned int const& std::min<unsigned int>(unsigned int const&, unsigned int const&)0x44 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()0x49c /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()0x4ac /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()0x4d4 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()0x4f8 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::close()0x2e4 /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::close()0x3ac /var/tmp//ccKCiEKq.o std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(char const*, std::_Ios_Openmode)0x300 /var/tmp//ccKCiEKq.o operator delete[](void*) 0x484 /var/tmp//ccKCiEKq.o std::basic_istream<char, std::char_traits<char> >::tellg() 0x334 /var/tmp//ccKCiEKq.o _Unwind_Resume 0x508 /var/tmp//ccKCiEKq.o ld: fatal: relocations remain against allocatable but non-writable sections collect2: ld returned 1 exit status </code></pre>

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