我刚试过运行我用我买的epson tm-t20打印机得到的样本java文件。这些类应该运行，但它们一直给我错误。我已经看了8个多小时了，现在我真的很沮丧。这是它向我投掷的例外：
Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: org/apache/xerces/parsers/DOMParser
at jpos.config.simple.xml.AbstractXercesRegPopulator.<init>(Unknown Source)
at jpos.config.simple.xml.XercesRegPopulator.<init>(Unknown Source)
at jpos.config.simple.xml.SimpleXmlRegPopulator.<init>(Unknown Source)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at java.lang.Class.newInstance0(Class.java:372)
at java.lang.Class.newInstance(Class.java:325)
at jpos.loader.simple.SimpleServiceManager.initRegPopulator(Unknown Source)
at jpos.loader.simple.SimpleServiceManager.initEntryRegistry(Unknown Source)
at jpos.loader.simple.SimpleServiceManager.init(Unknown Source)
at jpos.loader.simple.SimpleServiceManager.<init>(Unknown Source)
at jpos.loader.JposServiceLoader.<clinit>(Unknown Source)
at jpos.BaseJposControl.open(Unknown Source)
at postest.Step1Frame.processWindowEvent(Step1Frame.java:83)
at java.awt.Window.processEvent(Window.java:2003)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Window.dispatchEventImpl(Window.java:2713)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
at java.awt.EventQueue.access$000(EventQueue.java:101)
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:680)
at java.awt.EventQueue$4.run(EventQueue.java:678)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
以下是我一直在查看的示例代码：
POSPrinterControl19 ptr = (POSPrinterControl19)new POSPrinter();
JPanel contentPane;
JPanel jPanel_reciept = new JPanel();
TitledBorder titledBorder1;
GridBagLayout gridBagLayout1 = new GridBagLayout();
GridBagLayout gridBagLayout2 = new GridBagLayout();
JButton jButton_Print = new JButton();
/**Construct "Frame"*/
public Step1Frame() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
/**Form the component*/
private void jbInit() throws Exception {
//setIconImage(Toolkit.getDefaultToolkit().createImage(Step1Frame.class.getResource("[Your Icon]")));
contentPane = (JPanel) this.getContentPane();
titledBorder1 = new TitledBorder(BorderFactory.createEtchedBorder(Color.white,new Color(134, 134, 134)),"Receipt");
contentPane.setLayout(gridBagLayout1);
this.setSize(new Dimension(300, 180));
this.setTitle("Step 1 Print \"Hello JavaPOS\"");
jPanel_reciept.setLayout(gridBagLayout2);
jPanel_reciept.setBorder(titledBorder1);
jButton_Print.setText("Print");
jButton_Print.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
jButton_Print_actionPerformed(e);
}
});
contentPane.add(jPanel_reciept, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0
,GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(15, 0, 0, 0), 20, 20));
jPanel_reciept.add(jButton_Print, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0
,GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(5, 10, 5, 10), 130, 0));
}
/**
* Outline The processing code required in order to enable
* or to disable use of service is written here.
* @exception JposException This exception is fired toward the failure of
* the method which JavaPOS defines.
*/
/**When the window was closed*/
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
this.closing();
}
/**When the window open*/
else if (e.getID() == WindowEvent.WINDOW_OPENED) {
// JavaPOS's code for Step1
try {
//Open the device.
//Use the name of the device that connected with your computer.
//ptr.clearPrintArea();
ptr.open("POSPrinter");
//Get the exclusive control right for the opened device.
//Then the device is disable from other application.
ptr.claim(1000);
//Enable the device.
ptr.setDeviceEnabled(true);
}
catch(JposException ex) {
}
}
// JavaPOS's code for Step1--END
}
//***********************Button*************************************************
/**
* Outline The code for using the most standard method "PrintNormal"
* to print is described.
*/
void jButton_Print_actionPerformed(ActionEvent e) {
// JavaPOS's code for Step1
try{
//printNormal(int station, String data)
//A string is sent by using the method "printNormal", and it is printed.
// "\n" is the standard code for starting a new line.
// When the end of the line have no "\n",printing by
// using the method "printNormal" doesn't start, may be.
ptr.printNormal(POSPrinterConst.PTR_S_RECEIPT,"Hello JavaPOS\n");
}
catch(JposException ex){
}
// JavaPOS's code for Step1--END
}
//***********************Method*************************************************
/**
* Outline The code to finish a service.
*/
void closing(){
// JavaPOS's code for Step1
try{
//Cancel the device.
ptr.setDeviceEnabled(false);
//Release the device exclusive control right.
ptr.release();
//Finish using the device.
ptr.close();
}
catch(JposException ex){
}
// JavaPOS's code for Step1--END
System.exit(0);
}
答案 0 :(得分：1)
你必须在项目类路径中添加一些额外的依赖库，其中一个似乎是apache xerces XML解析器，所以基本上你必须将该jar库添加到类路径中。
你可以找到apache xerces XML解析器here。
答案 1 :(得分：1)
对于我类org / apache / xerces / parsers / DOMParser缺失。您可以从maven repository xercesImpl.jar
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