Java中有用的环境设置列表 [英] List of useful environment settings in Java

问题描述

如果有一个存储JVM运行时信息的（可能是静态的）方法/字段的综合列表，我一直想知道很长一段时间。一个不完整的示例列表：

I've been wondering a long time if there was a comprehensive list of (probably static) methods/fields that store runtime information for the JVM. An incomplete list of examples:

• System.out / System.in


• System.currentTimeMillis（ ）


• System.getProperty（）


• System.getConsole（）


• Runtime.freeMemory（）


• Etc

• System.out / System.in
• System.currentTimeMillis()
• System.getProperty()
• System.getConsole()
• Runtime.freeMemory()
• Etc

有没有人有链接或其他什么？

Does anyone have a link or something?

编辑：
我没有那么愚蠢，没有检查系统和运行时的文档：P
我只是想知道是否有其他类的类似方法来确定存储您正在运行的机器的状态。

I'm not so dumb as to have not checked the docs for System and Runtime :P I was just wondering if there were other classes where similar methods to determine the state of the machine you're running on are stored.

推荐答案

一般属性

我使用这段代码来处理一些我特别感兴趣的Java类已知的东西。

General Properties

I use this code to get a handle on some of the things known to Java classes that are of particular interest to me.

import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.util.*;

import java.security.*;

/** A small GUId app. that shows many system and environment properties.
Designed to be compatible with Java 1.4+ (hence many requirements like
no foreach, no generics, no StringBuilder..).
@author Andrew Thompson
@version 2008-06-29
 */
class SystemProperties {

    static String sentence = "The quick brown fox jumped over the lazy dog.";
    static String sep = System.getProperty("line.separator");
    static String fontText =
            sentence +
            sep +
            sentence.toUpperCase() +
            sep +
            "0123456789 !@#$%^&*()_+ []\\;',./ {}|:\"<>?";

    static String[] convertObjectToSortedStringArray(Object[] unsorted) {
        String[] sorted = new String[unsorted.length];
        for (int ii = 0; ii < sorted.length; ii++) {
            sorted[ii] = (String) unsorted[ii];
        }
        Arrays.sort(sorted);
        return sorted;
    }

    static String dataPairToTableRow(String property, Object value) {
        String val = valueToString(property, value);
        return "<tr>" +
                "<th>" +
                "<code>" +
                property +
                "</code>" +
                "</th>" +
                "<td>" +
                val +
                "</td>" +
                "</tr>";
    }

    static String valueToString(String property, Object value) {
        if (value instanceof Color) {
            Color color = (Color) value;
            String converted =
                    "<div style='width: 100%; height: 100%; " +
                    "background-color: #" +
                    Integer.toHexString(color.getRed()) +
                    Integer.toHexString(color.getGreen()) +
                    Integer.toHexString(color.getBlue()) +
                    ";'>" +
                    value.toString() +
                    "</div>";
            return converted;
        } else if (property.toLowerCase().endsWith("path") ||
                property.toLowerCase().endsWith("dirs")) {
            return delimitedToHtmlList(
                    (String) value,
                    System.getProperty("path.separator"));
        } else {
            return value.toString();
        }
    }

    static String delimitedToHtmlList(String values, String delimiter) {
        String[] parts = values.split(delimiter);
        StringBuffer sb = new StringBuffer();
        sb.append("<ol>");
        for (int ii = 0; ii < parts.length; ii++) {
            sb.append("<li>");
            sb.append(parts[ii]);
            sb.append("</li>");
        }
        return sb.toString();
    }

    static Component getExampleOfFont(String fontFamily) {
        Font font = new Font(fontFamily, Font.PLAIN, 24);
        JTextArea ta = new JTextArea();
        ta.setFont(font);
        ta.setText(fontText);
        ta.setEditable(false);
        // don't allow these to get focus, as it
        // interferes with desired scroll behavior
        ta.setFocusable(false);
        return ta;
    }

    static public JScrollPane getOutputWidgetForContent(String content) {
        JEditorPane op = new JEditorPane();
        op.setContentType("text/html");
        op.setEditable(false);

        op.setText(content);

        return new JScrollPane(op);
    }

    public static void main(String[] args) {
        JTabbedPane tabPane = new JTabbedPane();
        StringBuffer sb;
        String header = "<html><body><table border=1 width=100%>";

        sb = new StringBuffer(header);
        Properties prop = System.getProperties();
        String[] propStrings = convertObjectToSortedStringArray(
                prop.stringPropertyNames().toArray());
        for (int ii = 0; ii < propStrings.length; ii++) {
            sb.append(
                    dataPairToTableRow(
                    propStrings[ii],
                    System.getProperty(propStrings[ii])));
        }
        tabPane.addTab(
                "System",
                getOutputWidgetForContent(sb.toString()));

        sb = new StringBuffer(header);
        Map environment = System.getenv();
        String[] envStrings = convertObjectToSortedStringArray(
                environment.keySet().toArray());
        for (int ii = 0; ii < envStrings.length; ii++) {
            sb.append(
                    dataPairToTableRow(
                    envStrings[ii],
                    environment.get(envStrings[ii])));
        }
        tabPane.addTab(
                "Environment",
                getOutputWidgetForContent(sb.toString()));

        sb = new StringBuffer(header);
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice[] gs = ge.getScreenDevices();
        for (int j = 0; j < gs.length; j++) {
            GraphicsDevice gd = gs[j];
            sb.append(
                    dataPairToTableRow(
                    "Device " + j,
                    gd.toString() +
                    "  " +
                    gd.getIDstring()));
            GraphicsConfiguration[] gc =
                    gd.getConfigurations();
            for (int i = 0; i < gc.length; i++) {
                sb.append(
                        dataPairToTableRow(
                        "Config " +
                        i,
                        (int) gc[i].getBounds().getWidth() +
                        "x" +
                        (int) gc[i].getBounds().getHeight() +
                        " " +
                        gc[i].getColorModel() +
                        ", " +
                        "  Accelerated: " +
                        gc[i].getImageCapabilities().isAccelerated() +
                        "  True Volatile: " +
                        gc[i].getImageCapabilities().isTrueVolatile()));
            }
        }
        tabPane.addTab(
                "Graphics Environment",
                getOutputWidgetForContent(sb.toString()));

        String[] fonts = ge.getAvailableFontFamilyNames();
        JPanel fontTable = new JPanel(new BorderLayout(3, 1));
        // to enable key based scrolling in the font panel
        fontTable.setFocusable(true);
        JPanel fontNameCol = new JPanel(new GridLayout(0, 1, 2, 2));
        JPanel fontExampleCol = new JPanel(new GridLayout(0, 1, 2, 2));
        fontTable.add(fontNameCol, BorderLayout.WEST);
        fontTable.add(fontExampleCol, BorderLayout.CENTER);
        for (int ii = 0; ii < fonts.length; ii++) {
            fontNameCol.add(new JLabel(fonts[ii]));
            fontExampleCol.add(getExampleOfFont(fonts[ii]));
        }
        tabPane.add("Fonts", new JScrollPane(fontTable));

        sb = new StringBuffer(header);

        sb.append("<thead>");
        sb.append("<tr>");
        sb.append("<th>");
        sb.append("Code");
        sb.append("</th>");
        sb.append("<th>");
        sb.append("Language");
        sb.append("</th>");
        sb.append("<th>");
        sb.append("Country");
        sb.append("</th>");
        sb.append("<th>");
        sb.append("Variant");
        sb.append("</th>");
        sb.append("</tr>");
        sb.append("</thead>");

        Locale[] locales = Locale.getAvailableLocales();
        SortableLocale[] sortableLocale = new SortableLocale[locales.length];
        for (int ii = 0; ii < locales.length; ii++) {
            sortableLocale[ii] = new SortableLocale(locales[ii]);
        }
        Arrays.sort(sortableLocale);
        for (int ii = 0; ii < locales.length; ii++) {
            String prefix = "";
            String suffix = "";
            Locale locale = sortableLocale[ii].getLocale();
            if (locale.equals(Locale.getDefault())) {
                prefix = "<b>";
                suffix = "</b>";
            }
            sb.append(dataPairToTableRow(
                    prefix +
                    locale.toString() +
                    suffix,
                    prefix +
                    locale.getDisplayLanguage() +
                    suffix +
                    "</td><td>" +
                    prefix +
                    locale.getDisplayCountry() +
                    suffix +
                    "</td><td>" +
                    prefix +
                    locale.getDisplayVariant() +
                    suffix));
        }
        tabPane.add("Locales",
                getOutputWidgetForContent(sb.toString()));

        Locale.getDefault();
        int border = 5;
        JPanel p = new JPanel(new BorderLayout());
        p.setBorder(new EmptyBorder(border, border, border, border));
        p.add(tabPane, BorderLayout.CENTER);
        p.setPreferredSize(new Dimension(400, 400));
        JFrame f = new JFrame("Properties");
        f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        f.getContentPane().add(p, BorderLayout.CENTER);
        f.pack();
        f.setMinimumSize(f.getPreferredSize());
        f.setSize(600, 500);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

class SortableLocale implements Comparable {

    Locale locale;

    SortableLocale(Locale locale) {
        this.locale = locale;
    }

    public String toString() {
        return locale.toString();
    }

    public Locale getLocale() {
        return locale;
    }

    public int compareTo(Object object2) {
        SortableLocale locale2 = (SortableLocale) object2;
        //Locale locale2 = (Locale)object2;
        return locale.toString().compareTo(
                locale2.toString());
    }
}

媒体

与合成和采样声音以及图像相关的属性。

Media

Properties related to synthesized and sampled sound, and images.

/*
<applet
    code='MediaTypes'
    width='900'
    height='600'>
<param name='show' value='Sound|Sampled|Mixers|Primary Sound Capture Driver'>
</applet>
*/
import javax.imageio.ImageIO;
import javax.sound.sampled.*;
import javax.sound.midi.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.tree.*;
import javax.swing.event.*;
import javax.swing.text.Position;

public class MediaTypes extends JApplet {

    JTable table;
    boolean sortable = false;
    JTree tree;

    @Override
    public void init() {
        Runnable r = () -> {
            MediaTypes mediaTypes = new MediaTypes();

            String show = "";
            if (getParameter("show")!=null) {
                show = getParameter("show");
            }

            JPanel p = new JPanel();
            mediaTypes.createGui(p, show);
            add(p);
            validate();
        };
        SwingUtilities.invokeLater(r);
    }

    public static void main(String[] args) {
        Runnable r = () -> {
            MediaTypes mediaTypes = new MediaTypes();

            JPanel p = new JPanel();
            mediaTypes.createGui(p);
            JOptionPane.showMessageDialog(null,p);
        };
        SwingUtilities.invokeLater(r);
    }

    public Object[][] mergeArrays(String name1, Object[] data1, String name2, Object[] data2) {
        Object[][] data = new Object[data1.length+data2.length][2];
        for (int ii=0; ii<data1.length; ii++) {
            data[ii][0] = name1;
            data[ii][1] = data1[ii];
        }
        int offset = data1.length;
        for (int ii=offset; ii<data.length; ii++) {
            data[ii][0] = name2;
            data[ii][1] = data2[ii-offset];
        }
        return data;
    }

    public void createGui(JPanel panel) {
        createGui(panel, "");
    }

    public String getShortLineName(String name) {
        String[] lineTypes = {
            "Clip",
            "SourceDataLine",
            "TargetDataLine",
            "Speaker",
            "Microphone",
            "Master Volume",
            "Line In"
        };
        for (String shortName : lineTypes) {
            if ( name.toLowerCase().replaceAll("_", " ").contains(shortName.toLowerCase() )) {
                return shortName;
            }
        }
        return name;
    }

    public void createGui(JPanel panel, String path) {

        //DefaultMutableTreeNode selected = null;

        panel.setLayout( new BorderLayout(5,5) );
        final JLabel output = new JLabel("Select a tree leaf to see the details.");
        panel.add(output, BorderLayout.SOUTH);

        table = new JTable();
        try {
            table.setAutoCreateRowSorter(true);
            sortable = true;
        } catch (Throwable ignore) {
            // 1.6+ functionality - not vital
        }
        JScrollPane tableScroll = new JScrollPane(table);
        Dimension d = tableScroll.getPreferredSize();
        d = new Dimension(450,d.height);
        tableScroll.setPreferredSize(d);
        panel.add( tableScroll, BorderLayout.CENTER );

        DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Media");
        DefaultTreeModel treeModel = new DefaultTreeModel(rootNode);

        DefaultMutableTreeNode imageNode = new DefaultMutableTreeNode("Image");
        rootNode.add(imageNode);

        Object[][] data;
        int offset;
        String[] columnNames;

        data = mergeArrays(
            "Reader",
            ImageIO.getReaderFileSuffixes(),
            "Writer",
            ImageIO.getWriterFileSuffixes() );
        columnNames = new String[]{"Input/Output", "Image File Suffixes"};
        MediaData md = new MediaData( "Suffixes", columnNames, data);
        imageNode.add(new DefaultMutableTreeNode(md));

        data = mergeArrays(
            "Reader",
            ImageIO.getReaderMIMETypes(),
            "Writer",
            ImageIO.getWriterMIMETypes() );
        columnNames = new String[]{"Input/Output", "Image MIME Types"};
        md = new MediaData( "MIME", columnNames, data);
        imageNode.add(new DefaultMutableTreeNode(md));

        DefaultMutableTreeNode soundNode = new DefaultMutableTreeNode("Sound");
        rootNode.add(soundNode);

        DefaultMutableTreeNode soundSampledNode = new DefaultMutableTreeNode("Sampled");
        soundNode.add(soundSampledNode);

        md = new MediaData("Suffixes", "Sound File Suffixes", AudioSystem.getAudioFileTypes());
        soundSampledNode.add(new DefaultMutableTreeNode(md));

        Mixer.Info[] mixerInfo = AudioSystem.getMixerInfo();
        String[][] mixerData = new String[mixerInfo.length][4];
        for (int ii=0; ii<mixerData.length; ii++) {
            mixerData[ii][0] = mixerInfo[ii].getName();
            mixerData[ii][1] = mixerInfo[ii].getVendor();
            mixerData[ii][2] = mixerInfo[ii].getVersion();
            mixerData[ii][3] = mixerInfo[ii].getDescription();
        }
        columnNames = new String[]{"Name", "Vendor", "Version", "Description"};
        md = new MediaData("Mixers", columnNames, mixerData);
        DefaultMutableTreeNode soundSampledMixersNode = new DefaultMutableTreeNode(md);
        soundSampledNode.add(soundSampledMixersNode);

        for (Mixer.Info mixerInfo1 : mixerInfo) {
            Mixer mixer = AudioSystem.getMixer(mixerInfo1);
            data = mergeArrays(
                    "Source",
                    mixer.getSourceLineInfo(),
                    "Target",
                    mixer.getTargetLineInfo() );
            columnNames = new String[]{ "Input/Output", "Line Info" };
            md = new MediaData(mixerInfo1.getName(), columnNames, data);
            DefaultMutableTreeNode soundSampledMixerNode = new DefaultMutableTreeNode(md);
            soundSampledMixersNode.add( soundSampledMixerNode );
            Line.Info[] source = mixer.getSourceLineInfo();
            Line.Info[] target = mixer.getTargetLineInfo();
            Line[] all = new Line[source.length + target.length];
            try {
                for (int jj=0; jj<source.length; jj++) {
                    all[jj] = AudioSystem.getLine(source[jj]);
                }
                for (int jj=source.length; jj<all.length; jj++) {
                    all[jj] = AudioSystem.getLine(target[jj-source.length]);
                }
                columnNames = new String[]{"Attribute", "Value"};
                for (Line line : all) {
                    Control[] controls = line.getControls();
                    if (line instanceof DataLine) {
                        DataLine dataLine = (DataLine)line;
                        AudioFormat audioFormat = dataLine.getFormat();
                        data = new Object[7+controls.length][2];

                        data[0][0] = "Channels";
                        data[0][1] = audioFormat.getChannels();

                        data[1][0] = "Encoding";
                        data[1][1] = audioFormat.getEncoding();

                        data[2][0] = "Frame Rate";
                        data[2][1] = audioFormat.getFrameRate();

                        data[3][0] = "Sample Rate";
                        data[3][1] = audioFormat.getSampleRate();

                        data[4][0] = "Sample Size (bits)";
                        data[4][1] = audioFormat.getSampleSizeInBits();

                        data[5][0] = "Big Endian";
                        data[5][1] = audioFormat.isBigEndian();

                        data[6][0] = "Level";
                        data[6][1] = dataLine.getLevel();

                    } else if (line instanceof Port) {
                        Port port = (Port)line;
                        Port.Info portInfo = (Port.Info)port.getLineInfo();
                        data = new Object[2+controls.length][2];

                        data[0][0] = "Name";
                        data[0][1] = portInfo.getName();

                        data[1][0] = "Source";
                        data[1][1] = portInfo.isSource();
                    } else {
                        System.out.println( "?? " + line );
                    }
                    int start = data.length-controls.length;
                    for (int kk=start; kk<data.length; kk++) {
                        data[kk][0] = "Control";
                        int index = kk-start;
                        data[kk][1] = controls[index];
                    }
                    md = new MediaData(getShortLineName(line.getLineInfo().toString()), columnNames, data);
                    soundSampledMixerNode.add(new DefaultMutableTreeNode(md));
                }
            } catch(Exception e) {
                e.printStackTrace();
            }
        }

        int[] midiTypes = MidiSystem.getMidiFileTypes();
        data = new Object[midiTypes.length][2];
        for (int ii=0; ii<midiTypes.length; ii++) {
            data[ii][0] = midiTypes[ii];
            String description = "Unknown";
            switch (midiTypes[ii]) {
                case 0:
                    description = "Single Track";
                    break;
                case 1:
                    description = "Multi Track";
                    break;
                case 2:
                    description = "Multi Song";
            }
            data[ii][1] = description;
        }
        columnNames = new String[]{"Type", "Description"};
        md = new MediaData("MIDI", columnNames, data);
        DefaultMutableTreeNode soundMIDINode = new DefaultMutableTreeNode(md);
        soundNode.add(soundMIDINode);

        columnNames = new String[]{
            "Attribute",
            "Value"};
        MidiDevice.Info[] midiDeviceInfo = MidiSystem.getMidiDeviceInfo() ;
        for (MidiDevice.Info midiDeviceInfo1 : midiDeviceInfo) {
            data = new Object[6][2];
            data[0][0] = "Name";
            data[0][1] = midiDeviceInfo1.getName();
            data[1][0] = "Vendor";
            data[1][1] = midiDeviceInfo1.getVendor();
            data[2][0] = "Version";
            String version = midiDeviceInfo1.getVersion();
            data[2][1] = version.replaceAll("Version ", "");
            data[3][0] = "Description";
            data[3][1] = midiDeviceInfo1.getDescription();
            data[4][0] = "Maximum Transmitters";
            data[5][0] = "Maximum Receivers";
            try {
                MidiDevice midiDevice = MidiSystem.getMidiDevice(midiDeviceInfo1);
                Object valueTransmitter;
                if (midiDevice.getMaxTransmitters()==AudioSystem.NOT_SPECIFIED) {
                    valueTransmitter = "Not specified";
                } else {
                    valueTransmitter = midiDevice.getMaxTransmitters();
                }
                Object valueReceiver;
                if (midiDevice.getMaxReceivers()==AudioSystem.NOT_SPECIFIED) {
                    valueReceiver = "Not specified";
                } else {
                    valueReceiver = midiDevice.getMaxReceivers();
                }
                data[4][1] = valueTransmitter;
                data[5][1] = valueReceiver;
            }catch(MidiUnavailableException mue) {
                data[4][1] = "Unknown";
                data[5][1] = "Unknown";
            }
            md = new MediaData(midiDeviceInfo1.getName(), columnNames, data);
            soundMIDINode.add( new DefaultMutableTreeNode(md) );
        }

        tree = new JTree(treeModel);
        tree.setRootVisible(false);
        tree.getSelectionModel().setSelectionMode
            (TreeSelectionModel.SINGLE_TREE_SELECTION);
        tree.addTreeSelectionListener((TreeSelectionEvent tse) -> {
            if (sortable) {
                output.setText("Click table column headers to sort.");
            }

            DefaultMutableTreeNode node = (DefaultMutableTreeNode)
                    tree.getLastSelectedPathComponent();

            if (node == null) return;

            Object nodeInfo = node.getUserObject();
            if (nodeInfo instanceof MediaData) {
                MediaData mediaData = (MediaData)nodeInfo;
                table.setModel( new DefaultTableModel(
                        mediaData.getData(),
                        mediaData.getColumnNames()) );
            }
        });

        for (int ii=0; ii<tree.getRowCount(); ii++) {
            tree.expandRow(ii);
        }

        String[] paths = path.split("\\|");
        int row = 0;
        TreePath treePath = null;
        for (String prefix : paths) {
            treePath = tree.getNextMatch( prefix, row, Position.Bias.Forward );
            row = tree.getRowForPath(treePath);
        }

        panel.add(new JScrollPane(tree),BorderLayout.WEST);

        tree.setSelectionPath(treePath);
        tree.scrollRowToVisible(row);
    }
}

class MediaData {

    String name;
    String[] columnNames;
    Object[][] data;

    MediaData(String name, String columnName, Object[] data) {
        this.name = name;

        columnNames = new String[1];
        columnNames[0] = columnName;

        this.data = new Object[data.length][1];
        for (int ii=0; ii<data.length; ii++) {
            this.data[ii][0] = data[ii];
        }
    }

    MediaData(String name, String[] columnNames, Object[][] data) {
        this.name = name;
        this.columnNames = columnNames;
        this.data = data;
    }

    @Override
    public String toString() {
        return name;
    }

    public String[] getColumnNames() {
        return columnNames;
    }

    public Object[][] getData() {
        return data;
    }
}

其他

您可能还会调查：

Other

You might also investigate:

• InetAddress


• KeyStore


• 经理
  
  
  
  
  • CookieManager
  
  
  • KeyManagerFactory
  
  
  • LogManager
  
  
  • InetAddress
  • KeyStore
  • Managers
    • CookieManager
    • KeyManagerFactory
    • LogManager

    这篇关于Java中有用的环境设置列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！