如何检测打印机是否连接到您的计算机？ [英] How to detect whether Printer is attached to your computer or not in Java?

问题描述

我正在使用swing Java创建一个GUI。我必须使用一个按钮打印，它将直接开始打印我设置的文件而不打开默认的打印对话框。
我必须首先检查打印机是否连接到我的电脑？

I am creating one GUI in swing Java. I have to use one button " Print " which will directly start printing the file I have set without opening the default Print dialog box. I have to check first whether printner is attached to my computer or not ?

推荐答案

可能正在使用 PrintServiceLookup ？

此类的实现为特定类型的打印服务（通常相当于打印机）提供查找服务。

Implementations of this class provide lookup services for print services (typically equivalent to printers) of a particular type.

DocFlavor flavor = DocFlavor.INPUT_STREAM.POSTSCRIPT;
PrintRequestAttributeSet aset = new HashPrintRequestHashAttributeSet();
aset.add(MediaSizeName.ISO_A4);
PrintService[] pservices =PrintServiceLookup.lookupPrintServices(flavor, aset);
if (pservices.length > 0) {
    DocPrintJob pj = pservices[0].createPrintJob();
    //....
}

注意：PrintService的数量如果有打印机，应该至少有一个。如果有实际打印机，则可能至少为2，因为您可以在计算机上安装纯软件打印机。另请参见此主题。

Note: the number of PrintService should be at least one iff there is a printer. Potentially at least 2 if there is an actual printer, since you can have pure software printers installed on your computer. See also this thread.

根据平台和jdk，它可以一些错误，但除此之外，以下方法应该至少列出打印机：

Depending on the platform and jdk, it can have some bug, but otherwise, the following method is supposed to at least list the printers:

import java.awt.print.*;
import javax.print.*;
import javax.print.attribute.*;
import java.text.*;
import javax.print.attribute.standard.*;

public class ShowPrinters {

    public ShowPrinters() {
    }

    public static void main(String[] args) {
        DocFlavor myFormat = DocFlavor.SERVICE_FORMATTED.PRINTABLE;
        PrintRequestAttributeSet aset = new HashPrintRequestAttributeSet();
        PrintService[] services =PrintServiceLookup.lookupPrintServices(myFormat, aset);
        System.out.println("The following printers are available");
        for (int i=0;i<services.length;i++) {
            System.out.println("  service name: "+services[i].getName());
        }
    }
}

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在 eclipse代码源，你看到使用PrinterState检查打印机是否实际连接：

---

In this eclipse code source, you have see the use of PrinterState to check if the printer is actually connected:

AttributeSet attributes = new HashPrintServiceAttributeSet(
    new PrinterName(printerName, Locale.getDefault()));
PrintService[] services = PrintServiceLookup.lookupPrintServices(
    DocFlavor.SERVICE_FORMATTED.PRINTABLE,
    attributes);
PrintService printService = services[0];
PrintServiceAttributeSet printServiceAttributes = printService.getAttributes();
PrinterState printerState = (PrinterState) printServiceAttributes.get(PrinterState.class);

检查printerState是否为空。注意：这可能并不总是足够（请参阅此主题）。

Check if printerState is not null. Note: this might not be always enough (see this thread).

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