如何通过jni4net，在Java应用中调用C#接口
Java开发者如果想要调用Windows的接口，需要使用JNI来创建一个桥接的DLL。jni4net为Java虚拟机(JVM)和.Net运行时(CLR)之间提供了桥梁。
下载jni4net，学习里面的代码实例
在环境变量中设置好JAVA_HOME和C:\Windows\Microsoft.NET\Framework\v3.5\csc.exe
解压JavaTwain，在dll目录中运行工程，编译出JavaTwain.dll
从jni4net中拷贝bin和lib到项目中
运行generateProxies.cmd
运行run.cmd
示例解析
C#层
在C#工程中添加引用DynamicDotNetTWAIN.dll
初始化Dynamic .NET TWAIN组件
public DotNetScanner() { // initialize TWAIN Component try { dynamicDotNetTwain = new Dynamsoft.DotNet.TWAIN.DynamicDotNetTwain(); dynamicDotNetTwain.OnPostAllTransfers += new Dynamsoft.DotNet.TWAIN.Delegate.OnPostAllTransfersHandler(this.dynamicDotNetTwain_OnPostAllTransfers); dynamicDotNetTwain.MaxImagesInBuffer = 64; dynamicDotNetTwain.IfAppendImage = true; dynamicDotNetTwain.IfThrowException = true; dynamicDotNetTwain.IfShowUI = false; dynamicDotNetTwain.IfThrowException = true; dynamicDotNetTwain.ScanInNewProcess = true; } catch { MessageBox.Show(dynamicDotNetTwain.ErrorString); } }创建JVM和CLR交互的接口
public interface IJavaProxy { bool AcquireImage(int iIndex); String[] GetSources(); bool RegisterListener(INativeProxy proxy); void CloseSource(); } public interface INativeProxy { bool Notify(String message, String value); }扫描图片，通知Java层加载
public bool AcquireImage(int iIndex) { try { //dynamicDotNetTwain.CloseSource(); bool success = dynamicDotNetTwain.SelectSourceByIndex(Convert.ToInt16(iIndex)); dynamicDotNetTwain.OpenSource(); dynamicDotNetTwain.AcquireImage(); } catch (Dynamsoft.DotNet.TWAIN.TwainException exp) { String errorstr = ""; errorstr += "Error " + exp.Code + "\r\n" + "Description: " + exp.Message + "\r\nPosition: " + exp.TargetSite + "\r\nHelp: " + exp.HelpLink + "\r\n"; MessageBox.Show(errorstr); } catch (Exception exp) { String errorstr = ""; errorstr += "ErrorMessage: " + exp.Message + "\r\n"; MessageBox.Show(errorstr); } return true; } private void dynamicDotNetTwain_OnPostAllTransfers() { //MessageBox.Show("dynamicDotNetTwain_OnPostAllTransfers"); if (dynamicDotNetTwain.MaxImagesInBuffer < 1) { return; } Image img = dynamicDotNetTwain.GetImage(0); img = resizeImage(img, new Size(480, 640)); img.Save("twain.png"); if (listener != null) { listener.Notify("data ready", "twain.png"); } }Java层
加载JavaTwain.j4n.dll
private void initTWAIN() { try { Bridge.init(); Bridge.LoadAndRegisterAssemblyFrom(new java.io.File("JavaTwain.j4n.dll")); } catch (Exception e) { e.printStackTrace(); } mScanner = new DotNetScanner(); mScanner.RegisterListener(this); }使用Swing来显示UI
public ScanDocuments() { super(new BorderLayout()); initTWAIN(); //Create a file chooser mFileChooser = new JFileChooser(); FileNameExtensionFilter filter = new FileNameExtensionFilter( ".png", "png"); mFileChooser.setFileFilter(filter); mLoad = new JButton("Load"); mLoad.addActionListener(this); mScan = new JButton("Scan"); mScan.addActionListener(this); // get sources mSources = mScanner.GetSources(); if (mSources != null) { mSourceList = new JComboBox(mSources); } else { mSourceList = new JComboBox(new String[]{"N/A"}); } mSourceList.setSelectedIndex(0); // button panel JPanel buttonPanel = new JPanel(); buttonPanel.add(mSourceList); buttonPanel.add(mScan); buttonPanel.add(mLoad); add(buttonPanel, BorderLayout.PAGE_START); // image panel JPanel imageViewer = new JPanel(); mImage = new JLabel(); mImage.setSize(480, 640); imageViewer.add(mImage); add(imageViewer, BorderLayout.CENTER); }来自： http://www.codepool.biz/ocr-barcode-twain/twain-sdk/java-twain-with-dynamic-net-twain-and-jni4net...
本文由用户 jopen 自行上传分享，仅供网友学习交流。所有权归原作者，若您的权利被侵害，请联系管理员。
转载本站原创文章，请注明出处，并保留原始链接、图片水印。
本站是一个以用户分享为主的开源技术平台，欢迎各类分享！