java调用c库实例

java由于语言限制，不能使用char*作为返回值。 局部变量的字符串不能正常返回，vc可以正常接收，java不能接收。

c语言

int __stdcall GetCharacterCodeJn(char* outjson, int* outjson_len)

　　

java语言

package softgranttest;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

import com.sun.jna.Library;
import com.sun.jna.Memory;
import com.sun.jna.Native;
import com.sun.jna.Pointer;

public class Test {

	 // 定义接口CLibrary，继承自com.sun.jna.Library
    public interface testdll extends Library {
        testdll Instance = (testdll) Native.loadLibrary("totfranjo"  , testdll.class);

        int GetYellopCouCod(Pointer outjson_pointer,Pointer outjson_len_pointer);

    }

    public static void main(String[] args) throws IOException {

    	Test_RRROOO();

    }

    /**
     * 特征码
     *
     * @throws UnsupportedEncodingException
     */
    private static void Test_RRROOO() throws UnsupportedEncodingException
    {

        String strRet = "";

        Pointer outjson_pointer = new Memory(1024);
        Pointer outjson_len_pointer = new Memory(8);

        int nRet = testdll.Instance.GetYellopCouCod(outjson_pointer,outjson_len_pointer);

        int outjson_len = outjson_len_pointer.getInt(0);
        byte[] bytOutjson = outjson_pointer.getByteArray(0, outjson_len);

        strRet = new String(bytOutjson, "gb2312");

        System.out.println(strRet);
    }

}