jna导入DLL出现Unable to load library问题

[jinling4388]

代码：

public class TestDlg extends JFrame implements ActionListener {
	private static final long serialVersionUID = -7495940408592595397L;
	private JPanel mainPanel;
	private Button b = new Button("设置目录");
	public TestDlg() {
		//设置框架初始化参数
		this.setTitle("二代证读取");
		this.setLocation(200, 50);
		
		/*初始化工作开始*/
		mainPanel = new JPanel();	//初始化主面板

		//添加按钮监视事件
		b.addActionListener(this);

		//将按钮添加到主面板
    		mainPanel.add(b);
	
 	   	//将主面板加入框架
 	         this.getContentPane().add(mainPanel);
		this.setResizable(false);
	    	this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setSize(660, 500);
    		this.setVisible(true);
	}
	
	//此接口一定要继承StdCallLibrary 否则读卡错误!
	public interface SynIDCardAPI extends StdCallLibrary  {
		SynIDCardAPI INSTANCE = (SynIDCardAPI)Native.loadLibrary("SynIDCardAPI", SynIDCardAPI.class);

		public int Syn_SetPhotoPath(int iOption, char[] cPhotopath);	
	}
    
	//继承自ActionListener
	public void actionPerformed(ActionEvent e) {   
		Object source = e.getSource();
		if (source == b) {
    			String strInfo = new String();
    			JFileChooser fileChooser = new JFileChooser(".");
    			fileChooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    			fileChooser.setDialogTitle("打开文件夹");
    			int ret = fileChooser.showOpenDialog(null);
    			if (ret == JFileChooser.APPROVE_OPTION) {
    				//文件夹路径
    				System.out.println(fileChooser.getSelectedFile().getAbsolutePath());
    				char[] strTmp  = fileChooser.getSelectedFile().getAbsolutePath().toCharArray();
    				int nRet = SynIDCardAPI.INSTANCE.Syn_SetPhotoPath(0,strTmp);
            			strInfo.format("照片存放路径设置为 %s,nRet = %d", strTmp, nRet);
    			}
    			else {
    				strInfo = "选取路径失败！";
    			}
			System.out.println(strInfo);
		}
		else
			System.out.println("Something   else");   
    }     
  
    public static void main(String[] args) {   
        new TestDlg();
    }   
}

其中，SynIDCardAPI.dll为C++编译的，放在项目目录\bin\com\synjones\angel下。

错误信息：
Exception in thread "AWT-EventQueue-0" java.lang.UnsatisfiedLinkError: Unable to load library 'SynIDCardAPI': ???????¨
at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:155)
at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:216)
at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:191)
at com.sun.jna.Library$Handler.<init>(Library.java:131)
at com.sun.jna.Native.loadLibrary(Native.java:279)
at com.sun.jna.Native.loadLibrary(Native.java:265)
at com.synjones.angel.TestDlg$SynIDCardAPI.<clinit>(TestDlg.java:173)
at com.synjones.angel.TestDlg.actionPerformed(TestDlg.java:209)
at java.awt.Button.processActionEvent(Unknown Source)
at java.awt.Button.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

[jinling4388]

顶起来，大家帮忙呀

[jinling4388]

相对路径换成绝对路径如下：
SynIDCardAPI INSTANCE = (SynIDCardAPI)Native.loadLibrary("E:\\测试程序\\DLL\\SynIDCardAPI", SynIDCardAPI.class);
程序就可以正确了，为什么？
我想用相对路径的话我要设置环境变量吗？还是我的DLL放置位置不对？

[老张-AI]

public class UnsatisfiedLinkError
extends LinkageError
当 Java 虚拟机无法找到声明为 native 的方法的适当本地语言定义时，
抛出该错误。 

路过 顶下

[墨水鱼]

把SynIDCardAPI.dll放到path路径下。最简单的，就是把SynIDCardAPI.dll放到c:\windows\system32里

[jinling4388]

[Quote=引用 1 楼 zl3450341 的回复:]
Java codepublicclass UnsatisfiedLinkErrorextends LinkageError
当 Java 虚拟机无法找到声明为native 的方法的适当本地语言定义时，
抛出该错误。
路过 顶下
[/Quote]

那怎么改呀？

回复3#：放过去了，问题依旧存在。

[lazy_virus]

我换成绝对路径还是出现Unable to load library

[yxssz]

放到system32
采用绝对路径
NativeLibrary.addSearchPath
System.setProperty("jna.library.path", "F:\\DF6100d\\df6100d\\WebRoot\\WEB-INF\\classes\\");
四种方法都试了，还是找不到

[hedyn]

我也遇到这种问题，是在64位win7上出现的，但同样的代码在32位xp上正常

[jinling4388]

我没用win7，用的XP

[wsnangua]

楼上64位的，换成32位jdk试试~~~我折腾了一天，终于知道问题所在了 T T~

[冰点青蛙]

[Quote=引用 10 楼 的回复:]

楼上64位的，换成32位jdk试试~~~我折腾了一天，终于知道问题所在了 T T~
[/Quote]
帮我解决了问题。你的头像真tm可爱！

[Sun_Wu]

10楼正解，谢了