如何使用Java在网络打印机上打印？

Question

Using Java, I need to print on network printer, which is not installed locally. I only know the printer name. All tutorials I've seen started with something like:

PrintService []services = PrinterJob.lookupPrintServices();

The problem is there can be no printers installed, so the services will be empty in that case. I need to set the printer name directly, not just enumerate through visible printers.

Answer 1

Java AWT Printing will not find a printer via a path if it is not registered to the Windows / Active Directory user that is running the printing application. You must register the printer path through Windows "Devices and Printers" as a printer for that user for it to be visible. Then, as that user, you must run lookupPrintServices to see the list of printers available and retrieve the proper PrintService by the exact name String listed.

/**
 * Retrieve the specified Print Service; will return null if not found.
 * @return
 */
public static PrintService findPrintService(String printerName) {

    PrintService service = null;
    
    // Get array of all print services - sort order NOT GUARANTEED!
    PrintService[] services = PrinterJob.lookupPrintServices();
    
    // Retrieve specified print service from the array
    for (int index = 0; service == null && index < services.length; index++) {
        
        if (services[index].getName().equalsIgnoreCase(printerName)) {

            service = services[index];
        }
    }

    // Return the print service
    return service;
}

/**
 * Retrieve a PrinterJob instance set with the PrinterService using the printerName.
 * 
 * @return
 * @throws Exception IllegalStateException if expected printer is not found.
 */
public static PrinterJob findPrinterJob(String printerName) throws Exception {

    // Retrieve the Printer Service
    PrintService printService = PrintUtility.findPrintService(printerName);

    // Validate the Printer Service
    if (printService == null) {

        throw new IllegalStateException("Unrecognized Printer Service \"" + printerName + '"');
    }
    
    // Obtain a Printer Job instance.
    PrinterJob printerJob = PrinterJob.getPrinterJob();
    
    // Set the Print Service.
    printerJob.setPrintService(printService);

    // Return Print Job
    return printerJob;
}

/**
 * Printer list does not necessarily refresh if you change the list of 
 * printers within the O/S; you can run this to refresh if necessary.
 */
public static void refreshSystemPrinterList() {

    Class[] classes = PrintServiceLookup.class.getDeclaredClasses();

    for (int i = 0; i < classes.length; i++) {

        if ("javax.print.PrintServiceLookup$Services".equals(classes[i].getName())) {

            sun.awt.AppContext.getAppContext().remove(classes[i]);
            break;
        }
    }
}

Answer 2

在我的情况下，出现身份验证错误，我找不到共享打印机，因为我使用 LocalUser 帐户搜索它们，使用另一个帐户或更改打印机授权我可以找到它。