paramutils.java

本文论述了一个前台笔记本销售系统的开发过程

package com.set.utils;

import javax.servlet.http.HttpServletRequest;

/**
 * This class assists skin writers in getting parameters.
 */
public class ParamUtils {

	/**
	 * Gets a parameter as a string.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return The value of the parameter or null if the parameter was not found
	 *         or if the parameter is a zero-length string.
	 */
	public static String getParameter(HttpServletRequest request, String name) {
		return getParameter(request, name, false);
	}

	public static String getParameter(HttpServletRequest request, String name,
			String defaultValue) {
		if (getParameter(request, name, false) == null) {
			return defaultValue;
		} else {
			return getParameter(request, name, false);
		}
	}

	/**
	 * Gets a parameter as a string.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @param emptyStringsOK
	 *            Return the parameter values even if it is an empty string.
	 * @return The value of the parameter or null if the parameter was not
	 *         found.
	 */
	public static String getParameter(HttpServletRequest request, String name,
			boolean emptyStringsOK) {
		String temp = request.getParameter(name);
		if (temp != null) {
			if (temp.equals("") && !emptyStringsOK) {
				return null;
			} else {
				return temp;
			}
		} else {
			return null;
		}
	}

	public static String getNotNullParam(HttpServletRequest request, String name) {
		String value = request.getParameter(name);
		if (value == null)
			value = "";
		return value.trim();
	}

	public static String getGBParam(HttpServletRequest request, String name) {
		// return StringUtils.toGBK(getNotNullParam(request,name));
		return "";
	}

	public static String getUnicodeParam(HttpServletRequest request, String name) {
		// return StringUtils.toUnicode(getNotNullParam(request,name));
		return "";
	}

	/**
	 * Gets a parameter as a boolean.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return True if the value of the parameter was "true", false otherwise.
	 */
	public static boolean getBooleanParameter(HttpServletRequest request,
			String name) {
		return getBooleanParameter(request, name, false);
	}

	/**
	 * Gets a parameter as a boolean.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return True if the value of the parameter was "true", false otherwise.
	 */
	public static boolean getBooleanParameter(HttpServletRequest request,
			String name, boolean defaultVal) {
		String temp = request.getParameter(name);
		if ("true".equals(temp) || "on".equals(temp)) {
			return true;
		} else if ("false".equals(temp) || "off".equals(temp)) {
			return false;
		} else {
			return defaultVal;
		}
	}

	/**
	 * Gets a parameter as an int.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return The int value of the parameter specified or the default value if
	 *         the parameter is not found.
	 */
	public static int getIntParameter(HttpServletRequest request, String name,
			int defaultNum) {
		String temp = request.getParameter(name);
		if (temp != null && !temp.equals("")) {
			int num = defaultNum;
			try {
				num = Integer.parseInt(temp);
			} catch (Exception ignored) {
			}
			return num;
		} else {
			return defaultNum;
		}
	}

	/**
	 * Gets a list of int parameters.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @param defaultNum
	 *            The default value of a parameter, if the parameter can't be
	 *            converted into an int.
	 */
	public static int[] getIntParameters(HttpServletRequest request,
			String name, int defaultNum) {
		String[] paramValues = request.getParameterValues(name);
		if (paramValues == null) {
			return null;
		}
		if (paramValues.length < 1) {
			return new int[0];
		}
		int[] values = new int[paramValues.length];
		for (int i = 0; i < paramValues.length; i++) {
			try {
				values[i] = Integer.parseInt(paramValues[i]);
			} catch (Exception e) {
				values[i] = defaultNum;
			}
		}
		return values;
	}

	/**
	 * Gets a parameter as a double.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return The double value of the parameter specified or the default value
	 *         if the parameter is not found.
	 */
	public static double getDoubleParameter(HttpServletRequest request,
			String name, double defaultNum) {
		String temp = request.getParameter(name);
		if (temp != null && !temp.equals("")) {
			double num = defaultNum;
			try {
				num = Double.parseDouble(temp);
			} catch (Exception ignored) {
			}
			return num;
		} else {
			return defaultNum;
		}
	}

	/**
	 * Gets a parameter as a long.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return The long value of the parameter specified or the default value if
	 *         the parameter is not found.
	 */
	public static long getLongParameter(HttpServletRequest request,
			String name, long defaultNum) {
		String temp = request.getParameter(name);
		if (temp != null && !temp.equals("")) {
			long num = defaultNum;
			try {
				num = Long.parseLong(temp);
			} catch (Exception ignored) {
			}
			return num;
		} else {
			return defaultNum;
		}
	}

	/**
	 * Gets a list of long parameters.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @param defaultNum
	 *            The default value of a parameter, if the parameter can't be
	 *            converted into a long.
	 */
	public static long[] getLongParameters(HttpServletRequest request,
			String name, long defaultNum) {
		String[] paramValues = request.getParameterValues(name);
		if (paramValues == null) {
			return null;
		}
		if (paramValues.length < 1) {
			return new long[0];
		}
		long[] values = new long[paramValues.length];
		for (int i = 0; i < paramValues.length; i++) {
			try {
				values[i] = Long.parseLong(paramValues[i]);
			} catch (Exception e) {
				values[i] = defaultNum;
			}
		}
		return values;
	}

	/**
	 * Gets a parameter as a string.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @return The value of the parameter or null if the parameter was not found
	 *         or if the parameter is a zero-length string.
	 */
	public static String getAttribute(HttpServletRequest request, String name) {
		return getAttribute(request, name, false);
	}

	/**
	 * Gets a parameter as a string.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the parameter you want to get
	 * @param emptyStringsOK
	 *            Return the parameter values even if it is an empty string.
	 * @return The value of the parameter or null if the parameter was not
	 *         found.
	 */
	public static String getAttribute(HttpServletRequest request, String name,
			boolean emptyStringsOK) {
		String temp = (String) request.getAttribute(name);
		if (temp != null) {
			if (temp.equals("") && !emptyStringsOK) {
				return null;
			} else {
				return temp;
			}
		} else {
			return null;
		}
	}

	/**
	 * Gets an attribute as a boolean.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the attribute you want to get
	 * @return True if the value of the attribute is "true", false otherwise.
	 */
	public static boolean getBooleanAttribute(HttpServletRequest request,
			String name) {
		String temp = (String) request.getAttribute(name);
		if (temp != null && temp.equals("true")) {
			return true;
		} else {
			return false;
		}
	}

	/**
	 * Gets an attribute as a int.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the attribute you want to get
	 * @return The int value of the attribute or the default value if the
	 *         attribute is not found or is a zero length string.
	 */
	public static int getIntAttribute(HttpServletRequest request, String name,
			int defaultNum) {
		String temp = (String) request.getAttribute(name);
		if (temp != null && !temp.equals("")) {
			int num = defaultNum;
			try {
				num = Integer.parseInt(temp);
			} catch (Exception ignored) {
			}
			return num;
		} else {
			return defaultNum;
		}
	}

	/**
	 * Gets an attribute as a long.
	 * 
	 * @param request
	 *            The HttpServletRequest object, known as "request" in a JSP
	 *            page.
	 * @param name
	 *            The name of the attribute you want to get
	 * @return The long value of the attribute or the default value if the
	 *         attribute is not found or is a zero length string.
	 */
	public static long getLongAttribute(HttpServletRequest request,
			String name, long defaultNum) {
		String temp = (String) request.getAttribute(name);
		if (temp != null && !temp.equals("")) {
			long num = defaultNum;
			try {
				num = Long.parseLong(temp);
			} catch (Exception ignored) {
			}
			return num;
		} else {
			return defaultNum;
		}
	}
}