ParamUtils参数接受工具类的代码及介绍

ParamUtils这个类，觉得以后做项目时可以把做成一个单独的组件使用，解决了request.getParameter()时只能取出String的问题。

/**
* $RCSfile: ParamUtils.java,v $
* $Revision: 1.6 $
* $Date: 2001/07/31 05:38:18 $
*
* Copyright (C) 1999-2001 CoolServlets, Inc. All rights reserved.
*
* This software is the proprietary information of CoolServlets, Inc.
* Use is subject to license terms.
*/

package com.jivesoftware.forum.util;

import javax.servlet.http.*;

/**
* 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);
    }

    /**
     * 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;
        }
    }

    /**
     * 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;
        }
     }
}