jhostname.java

JAVA网络学习例题

//jHostName.java
import java.applet.Applet;
import java.awt.*;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class jHostName extends Applet
{
    //变量定义
    InetAddress localHost;
    FontMetrics fontMatric;
    Font dispFont;
    Color txtColor;
    Color bgColor;
    String fontName;
    String fromHost;
    String preString;
    String postString;
    int fontSize;
    int fontStyle;
    //构造函数
    public jHostName()
    {
        localHost = null;
        fontMatric = null;
        dispFont = null;
        txtColor = null;
        bgColor = null;
        fontName = null;
        fromHost = null;
        preString = null;
        postString = null;
        fontSize = 0;
        fontStyle = 0;
        fromHost = new String();
        preString = new String();
        postString = new String();
    }
    //初始化小程序
    public void init()
    {
        String s;
        fontSize = (s = getParameter("Font_Size")) != null ? Integer.parseInt(s) : 24;
        txtColor = (s = getParameter("Text_Color")) != null ? new Color(Integer.parseInt(s, 16)) : Color.lightGray;
        bgColor = (s = getParameter("Bg_Color")) != null ? new Color(Integer.parseInt(s, 16)) : Color.black;
        fontName = getParameter("Font_Name");
        if(fontName == null)
            fontName = new String("TimesRoman");
        else
        if(fontName.equalsIgnoreCase("Helvetica"))
            fontName = new String("Helvetica");
        else
        if(fontName.equalsIgnoreCase("Couier"))
            fontName = new String("Courier");
        else
            fontName = new String("TimesRoman");
        if((s = getParameter("Font_Style")) == null)
            fontStyle = 1;
        else
        if(s.equalsIgnoreCase("Plain"))
            fontStyle = 0;
        else
        if(s.equalsIgnoreCase("Italic"))
            fontStyle = 2;
        else
        if(s.equalsIgnoreCase("BoldItalic"))
            fontStyle = 3;
        else
            fontStyle = 1;
        try
        {
            localHost = InetAddress.getLocalHost();
            fromHost = localHost.getHostName();
        }
        catch(UnknownHostException unknownhostexception)
        {
            fromHost = "Unidentified Visitor";
        }
        preString = getParameter("preString");
        if(preString == null)
            preString = " ";
        postString = getParameter("postString");
        if(postString == null)
            postString = " ";
        fromHost = preString + " " + fromHost + " " + postString;
        dispFont = new Font(fontName, fontStyle, fontSize);
        for(fontMatric = getFontMetrics(dispFont); fontMatric.stringWidth(fromHost) > getSize().width; fontMatric = getFontMetrics(dispFont))
        {
            fontSize = fontSize - 2;
            dispFont = new Font(fontName, fontStyle, fontSize);
        }

        for(; fontMatric.getHeight() > getSize().height - 10; fontMatric = getFontMetrics(dispFont))
        {
            fontSize = fontSize - 4;
            dispFont = new Font(fontName, fontStyle, fontSize);
        }

    }
    //画屏函数
    public void paint(Graphics g)
    {
        int i = (getSize().width - fontMatric.stringWidth(fromHost)) / 2;
        int j = (getSize().height + fontMatric.getHeight()) / 2;
        g.setFont(dispFont);
        g.setColor(bgColor);
        g.fillRect(0, 0, getSize().width, getSize().height);
        g.setColor(txtColor);
        g.drawString(fromHost, i, j);
    }
}