?? servletutilities.java
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package sjservlets;
/** A Servlet that contain various usefull small functions
* which will use by other servlet or/and JSP files
* <P>
* © 2002 Song Jing; may be freely used or adapted.
*/
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.util.Date;
import java.text.DateFormat;
import java.util.Locale;
/** Some simple time savers. Note that most are static methods.
* <P>
* Taken from Core Servlets and JavaServer Pages
* from Prentice Hall and Sun Microsystems Press,
* http://www.coreservlets.com/.
* © 2000 Marty Hall; may be freely used or adapted.
*/
public class ServletUtilities {
public static final String DOCTYPE =
"<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
"Transitional//EN\">";
public static String headWithTitle(String title) {
return(DOCTYPE + "\n" +
"<HTML>\n" +
"<HEAD><TITLE>" + title + "</TITLE></HEAD>\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<cookies.length; i++) {
Cookie cookie = cookies[i];
if (cookieName.equals(cookie.getName()))
return(cookie.getValue());
}
}
return(defaultValue);
}
/** Given an array of cookies and a name, this method tries
* to find and return the cookie from the array that has
* the given name. If there is no cookie matching the name
* in the array, null is returned.
*/
public static Cookie getCookie(Cookie[] cookies,
String cookieName) {
if (cookies != null) {
for(int i=0; i<cookies.length; i++) {
Cookie cookie = cookies[i];
if (cookieName.equals(cookie.getName()))
return(cookie);
}
}
return(null);
}
/** Given a string, this method replaces all occurrences of
* '<' with '<', all occurrences of '>' 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<input.length(); i++) {
c = input.charAt(i);
if (c == '<') {
filtered.append("<");
} else if (c == '>') {
filtered.append(">");
} else if (c == '"') {
filtered.append(""");
} else if (c == '&') {
filtered.append("&");
} else {
filtered.append(c);
}
}
return(filtered.toString());
}
// Builds a cascading style sheet with information
// on three levels of headings and overall
// foreground and background cover. Also tells
// Internet Explorer to change color of mailto link
// when mouse moves over it.
public static String makeStyleSheet(String headingFont,
int heading1Size,
String bodyFont,
int bodySize,
String fgColor,
String bgColor) {
int heading2Size = heading1Size*7/10;
int heading3Size = heading1Size*6/10;
String styleSheet =
"<STYLE TYPE=\"text/css\">\n" +
"<!--\n" +
".HEADING1 { font-size: " + heading1Size + "px;\n" +
" font-weight: bold;\n" +
" font-family: " + headingFont +
"Arial, Helvetica, sans-serif;\n" +
"}\n" +
".HEADING2 { font-size: " + heading2Size + "px;\n" +
" font-weight: bold;\n" +
" font-family: " + headingFont +
"Arial, Helvetica, sans-serif;\n" +
"}\n" +
".HEADING3 { font-size: " + heading3Size + "px;\n" +
" font-weight: bold;\n" +
" font-family: " + headingFont +
"Arial, Helvetica, sans-serif;\n" +
"}\n" +
"BODY { color: " + fgColor + ";\n" +
" background-color: " + bgColor + ";\n" +
" font-size: " + bodySize + "px;\n" +
" font-family: " + bodyFont +
"Times New Roman, Times, serif;\n" +
"}\n" +
"A:hover { color: red; }\n" +
"-->\n" +
"</STYLE>";
return(styleSheet);
}
// Replaces null strings (no such parameter name) or
// empty strings (e.g., if textfield was blank) with
// the replacement. Returns the original string otherwise.
public static String replaceIfMissing(String orig,
String replacement) {
if ((orig == null) || (orig.length() == 0)) {
return(replacement);
} else {
return(orig);
}
}
// Replaces null strings, empty strings, or the string
// "default" with the replacement.
// Returns the original string otherwise.
public static String replaceIfMissingOrDefault(String orig,
String replacement) {
if ((orig == null) ||
(orig.length() == 0) ||
(orig.equals("default"))) {
return(replacement);
} else {
return(orig + ", ");
}
}
// Takes a string representing an integer and returns it
// as an int. Returns a default if the string is null
// or in an illegal format.
public static int getSize(String sizeString, int defaultSize) {
try {
return(Integer.parseInt(sizeString));
} catch(NumberFormatException nfe) {
return(defaultSize);
}
}
// Given "Java,C++,Lisp", "Java C++ Lisp" or
// "Java, C++, Lisp", returns
// "<UL>
// <LI>Java
// <LI>C++
// <LI>Lisp
// </UL>"
public static String makeList(String listItems) {
StringTokenizer tokenizer =
new StringTokenizer(listItems, ", ");
String list = "<UL>\n";
while(tokenizer.hasMoreTokens()) {
list = list + " <LI>" + tokenizer.nextToken() + "\n";
}
list = list + "</UL>";
return(list);
}
public static Date stringToDate(String myDateStr) {
int inputYear = Integer.parseInt(myDateStr.substring(0,4)) - 1900;
int inputMonth = Integer.parseInt(myDateStr.substring(5,7)) - 1;
int inputDate = Integer.parseInt(myDateStr.substring(8,10));
return (new Date(inputYear, inputMonth, inputDate));
}
public static String dateToString(Date myDate) {
int outputYear = myDate.getYear();
int outputMonth = myDate.getMonth();
int outputDate = myDate.getDate();
return ((outputYear+1900) +"-" +(outputMonth+1) +"-" +(outputDate));
}
public static Date diffrenceDay(Date myDate, int difDay){
int myYear = myDate.getYear();
int myMonth = myDate.getMonth();
int myDay = myDate.getDate();
return(new Date(myYear, myMonth, myDay + difDay));
}
}
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