ServletUtilities.java Utility class that simplifies the output of the DOCTYPE and HEAD in servlets, among other things. Used by most remaining servlets in the chapter.
package cwp;
import javax.servlet.*;
import javax.servlet.http.*;
/** Some simple time savers. Note that most are static methods.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class ServletUtilities {
public static final String DOCTYPE =
"";
public static String headWithTitle(String title) {
return(DOCTYPE + "\n" +
"\n" +
"\n");
}
/** Read a parameter with the specified name, convert it
* to an int, and return it. Return the designated default
* value if the parameter doesn't exist or if it is an
* illegal integer format.
*/
public static int getIntParameter(HttpServletRequest request,
String paramName,
int defaultValue) {
String paramString = request.getParameter(paramName);
int paramValue;
try {
paramValue = Integer.parseInt(paramString);
} catch(NumberFormatException nfe) { // null or bad format
paramValue = defaultValue;
}
return(paramValue);
}
/** Given an array of Cookies, a name, and a default value,
* this method tries to find the value of the cookie with
* the given name. If there is no cookie matching the name
* in the array, then the default value is returned instead.
*/
public static String getCookieValue(Cookie[] cookies,
String cookieName,
String defaultValue) {
if (cookies != null) {
for(int i=0; i' with
* '>', and (to handle cases that occur inside attribute
* values), all occurrences of double quotes with
* '"' and all occurrences of '&' with '&'.
* Without such filtering, an arbitrary string
* could not safely be inserted in a Web page.
*/
public static String filter(String input) {
StringBuffer filtered = new StringBuffer(input.length());
char c;
for(int i=0; i') {
filtered.append(">");
} else if (c == '"') {
filtered.append(""");
} else if (c == '&') {
filtered.append("&");
} else {
filtered.append(c);
}
}
return(filtered.toString());
}
}
Aug 15
ServletUtilities.java Utility class that simplifies the output of the DOCTYPE and HEAD in servlets, among other things. Used by most remaining servlets in the chapter.
Aug 15
SimplerHelloWWW.java Servlet that uses ServletUtilities to simplify the generation of the DOCTYPE and HEAD part of the servlet.
SimplerHelloWWW.java Servlet that uses ServletUtilities to simplify the generation of the DOCTYPE and HEAD part of the servlet.
package cwp;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
/** Simple servlet that generates HTML. This variation of
* HelloWWW uses the ServletUtilities utility class
* to generate the DOCTYPE, HEAD, and TITLE.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class SimplerHelloWWW extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println(ServletUtilities.headWithTitle("Hello WWW") +
"\n" +
"
Hello WWW
\n" +
"");
}
}
Servlet Utilities
package cwp;
import javax.servlet.*;
import javax.servlet.http.*;
/** Some simple time savers. Note that most are static methods.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* May be freely used or adapted.
*/
public class ServletUtilities {
public static final String DOCTYPE =
"";
public static String headWithTitle(String title) {
return(DOCTYPE + "\n" +
"\n" +
"\n");
}
/** Read a parameter with the specified name, convert it
* to an int, and return it. Return the designated default
* value if the parameter doesn't exist or if it is an
* illegal integer format.
*/
public static int getIntParameter(HttpServletRequest request,
String paramName,
int defaultValue) {
String paramString = request.getParameter(paramName);
int paramValue;
try {
paramValue = Integer.parseInt(paramString);
} catch(NumberFormatException nfe) { // null or bad format
paramValue = defaultValue;
}
return(paramValue);
}
/** Given an array of Cookies, a name, and a default value,
* this method tries to find the value of the cookie with
* the given name. If there is no cookie matching the name
* in the array, then the default value is returned instead.
*/
public static String getCookieValue(Cookie[] cookies,
String cookieName,
String defaultValue) {
if (cookies != null) {
for(int i=0; i' with
* '>', and (to handle cases that occur inside attribute
* values), all occurrences of double quotes with
* '"' and all occurrences of '&' with '&'.
* Without such filtering, an arbitrary string
* could not safely be inserted in a Web page.
*/
public static String filter(String input) {
StringBuffer filtered = new StringBuffer(input.length());
char c;
for(int i=0; i') {
filtered.append(">");
} else if (c == '"') {
filtered.append(""");
} else if (c == '&') {
filtered.append("&");
} else {
filtered.append(c);
}
}
return(filtered.toString());
}
}
Aug 14
HelloWWW.java Servlet that generates HTML. This and all remaining servlets are in the cwp package and therefore should be installed in the cwp subdirectory.
HelloWWW.java Servlet that generates HTML. This and all remaining servlets are in the cwp package and therefore should be installed in the cwp subdirectory.
package cwp;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
/** Simple servlet that generates HTML.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class HelloWWW extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String docType =
"\n";
out.println(docType +
"\n" +
"\n" +
"\n" +
"
Aug 14
HelloWorld.java Simple servlet that generates plain text.
HelloWorld.java Simple servlet that generates plain text.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
/** Very simplistic servlet that generates plain text.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class HelloWorld extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("Hello World");
}
}
Aug 13
ServletTemplate.java Starting point for servlets.
ServletTemplate.java Starting point for servlets.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
/** Servlet template.
*
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class ServletTemplate extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// Use "request" to read incoming HTTP headers
// (e.g., cookies) and query data from HTML forms.
// Use "response" to specify the HTTP response status
// code and headers (e.g. the content type, cookies).
PrintWriter out = response.getWriter();
// Use "out" to send content to browser
}
}
Aug 13
StringBean.java Bean used to demonstrate jsp:useBean, etc. Remember to install it in the WEB-INF/classes/cwp directory.
StringBean.java Bean used to demonstrate jsp:useBean, etc. Remember to install it in the WEB-INF/classes/cwp directory.
package cwp;
/** A simple bean that has a single String property
* called message.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class StringBean {
private String message = "No message specified";
public String getMessage() {
return(message);
}
public void setMessage(String message) {
this.message = message;
}
}
Aug 12
PluginApplet.jsp Page that demonstrates the use of jsp:plugin.
PluginApplet.jsp Page that demonstrates the use of jsp:plugin. Requires you to compile and install PluginApplet.java, TextPanel.java, DrawingPanel.java, and WindowUtilities.java Since these are classes sent to the client to used by applets, the .class files should be in the same directory as the JSP page, not in the WEB-INF/classes directory where classes the server uses go. Uses the JSP-Styles style sheet. Warning: Allaire JRun 3.0 SP2 does not properly support jsp:plugin.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!--
Example of using jsp:plugin for an applet that uses Java 2.
Taken from Core Web Programming Java 2 Edition
from Prentice Hall and Sun Microsystems Press,
.
May be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Using jsp:plugin</TITLE>
<LINK REL=STYLESHEET
HREF="JSP-Styles.css"
TYPE="text/css">
</HEAD>
<BODY>
<TABLE BORDER=5 ALIGN="CENTER">
<TR><TH CLASS="TITLE">
Using jsp:plugin</TABLE>
<P>
<CENTER>
<jsp:plugin type="applet"
code="PluginApplet.class"
width="370" height="420">
</jsp:plugin>
</CENTER>
</BODY>
</HTML>
PluginApplet.java
import javax.swing.*;
/** An applet that uses Swing and Java 2D and thus requires
* the Java Plug-In.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class PluginApplet extends JApplet {
public void init() {
WindowUtilities.setNativeLookAndFeel();
setContentPane(new TextPanel());
}
}
TextPanel.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/** JPanel that places a panel with text drawn at various angles
* in the top part of the window and a JComboBox containing
* font choices in the bottom part.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class TextPanel extends JPanel
implements ActionListener {
private JComboBox fontBox;
private DrawingPanel drawingPanel;
public TextPanel() {
GraphicsEnvironment env =
GraphicsEnvironment.getLocalGraphicsEnvironment();
String[] fontNames = env.getAvailableFontFamilyNames();
fontBox = new JComboBox(fontNames);
setLayout(new BorderLayout());
JPanel fontPanel = new JPanel();
fontPanel.add(new JLabel("Font:"));
fontPanel.add(fontBox);
JButton drawButton = new JButton("Draw");
drawButton.addActionListener(this);
fontPanel.add(drawButton);
add(fontPanel, BorderLayout.SOUTH);
drawingPanel = new DrawingPanel();
fontBox.setSelectedItem("Serif");
drawingPanel.setFontName("Serif");
add(drawingPanel, BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent e) {
drawingPanel.setFontName((String)fontBox.getSelectedItem());
drawingPanel.repaint();
}
}
DrawingPanel.java
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
/** A window with text drawn at an angle. The font is
* set by means of the setFontName method.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
class DrawingPanel extends JPanel {
private Ellipse2D.Double circle =
new Ellipse2D.Double(10, 10, 350, 350);
private GradientPaint gradient =
new GradientPaint(0, 0, Color.red, 180, 180, Color.yellow,
true); // true means to repeat pattern
private Color[] colors = { Color.white, Color.black };
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
g2d.setPaint(gradient);
g2d.fill(circle);
g2d.translate(185, 185);
for (int i=0; i<16; i++) {
g2d.rotate(Math.PI/8.0);
g2d.setPaint(colors[i%2]);
g2d.drawString("jsp:plugin", 0, 0);
}
}
public void setFontName(String fontName) {
setFont(new Font(fontName, Font.BOLD, 35));
}
}
WindowUtilities.java
import javax.swing.*;
import java.awt.*;
/** A few utilities that simplify using windows in Swing.
* <P>
* Taken from Core Web Programming Java 2 Edition
* from Prentice Hall and Sun Microsystems Press,
* .
* May be freely used or adapted.
*/
public class WindowUtilities {
/** Tell system to use native look and feel, as in previous
* releases. Metal (Java) LAF is the default otherwise.
*/
public static void setNativeLookAndFeel() {
try {
UIManager.setLookAndFeel
(UIManager.getSystemLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting native LAF: " + e);
}
}
public static void setJavaLookAndFeel() {
try {
UIManager.setLookAndFeel
(UIManager.getCrossPlatformLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting Java LAF: " + e);
}
}
public static void setMotifLookAndFeel() {
try {
UIManager.setLookAndFeel
("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
} catch(Exception e) {
System.out.println("Error setting Motif LAF: " + e);
}
}
/** A simplified way to see a JPanel or other Container.
* Pops up a JFrame with specified Container
* as the content pane.
*/
public static JFrame openInJFrame(Container content,
int width,
int height,
String title,
Color bgColor) {
JFrame frame = new JFrame(title);
frame.setBackground(bgColor);
content.setBackground(bgColor);
frame.setSize(width, height);
frame.setContentPane(content);
frame.addWindowListener(new ExitListener());
frame.setVisible(true);
return(frame);
}
/** Uses Color.white as the background color. */
public static JFrame openInJFrame(Container content,
int width,
int height,
String title) {
return(openInJFrame(content, width, height, title, Color.white));
}
/** Uses Color.white as the background color, and the
* name of the Container's class as the JFrame title.
*/
public static JFrame openInJFrame(Container content,
int width,
int height) {
return(openInJFrame(content, width, height,
content.getClass().getName(),
Color.white));
}
}
