java 如何调用lib文件，别人写的程序反编译后报错，

[qq_33807124]

别人的程序：此段代码为识别验证码图片
public String obtainYzm(ServletContext application, String fn, String index)
{
byte[] vcode = new byte[1024];

String codePath = application.getRealPath("valicode") + "\\valicodeJ" + fn + "\\valicode" + index + ".jpg";//图片

String libPath = application.getRealPath("DllLib/OCR.lib");

int count = OcrDll.INSTANCE.OCRImage(codePath, libPath, vcode);
try
{
return new String(vcode, "GBK").trim();
}
catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return "";
}


OcrDll类：

package org.common;

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

public interface OcrDll
extends Library
{

public static final OcrDll INSTANCE = (OcrDll)Native.loadLibrary("DllLib/OCRDLL.dll", OcrDll.class);

public abstract int OCRImage(String s, String s1, byte abyte0[]);

}

请求大神们教教小弟如何调用lib文件。