Java URL Query Build createQueryStringFromMap(Map m, String ampersand, boolean encode)

Description

Builds a query string from a given map of parameters.

License

Open Source License

Parameter

Parameter	Description
m	A map of parameters
ampersand	String to use for ampersands (e.g. "&" or "&" )
encode	Whether or not to encode non-ASCII characters

Return

query string (with no leading "?")

Declaration

public static StringBuffer createQueryStringFromMap(Map<?, ?> m, String ampersand, boolean encode) 

Method Source Code

//package com.java2s;
/***********************************************************************************************************************
 * Copyright (c) 2008 empolis GmbH and brox IT Solutions GmbH. All rights reserved. This program and the accompanying
 * materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 * /*from  w  w  w  . ja  va2 s  . co m*/
 * Contributors: Dmitry Hazin (brox IT Solutions GmbH) - initial creator
 * Sebastian Voigt (brox IT Solutions GmbH)
 **********************************************************************************************************************/

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class Main {
    /**
     * Builds a query string from a given map of parameters.
     * 
     * @param m
     *          A map of parameters
     * @param ampersand
     *          String to use for ampersands (e.g. "&" or "&" )
     * @param encode
     *          Whether or not to encode non-ASCII characters
     * 
     * @return query string (with no leading "?")
     */
    public static StringBuffer createQueryStringFromMap(Map<?, ?> m, String ampersand, boolean encode) {
        final StringBuffer result = new StringBuffer("");
        final Set<?> entrySet = m.entrySet();
        final Iterator<?> entrySetIterator = entrySet.iterator();

        while (entrySetIterator.hasNext()) {
            final Map.Entry<?, ?> entry = (Map.Entry<?, ?>) entrySetIterator.next();
            final Object o = entry.getValue();

            if (o == null) {
                append(entry.getKey(), "", result, ampersand, encode);
            } else if (o instanceof String) {
                append(entry.getKey(), o, result, ampersand, encode);
            } else if (o instanceof String[]) {
                final String[] values = (String[]) o;

                for (int i = 0; i < values.length; i++) {
                    append(entry.getKey(), values[i], result, ampersand, encode);
                }
            } else {
                append(entry.getKey(), o, result, ampersand, encode);
            }
        }

        return result;
    }

    /**
     * Builds a query string from a given map of parameters.
     * 
     * @param m
     *          A map of parameters
     * @param ampersand
     *          String to use for ampersands (e.g. "&" or "&amp;" )
     * 
     * @return query string (with no leading "?")
     */
    public static StringBuffer createQueryStringFromMap(Map<?, ?> m, String ampersand) {
        return createQueryStringFromMap(m, ampersand, true);
    }

    /**
     * Appends new key and value pair to query string.
     * 
     * @param key
     *          parameter name
     * @param value
     *          value of parameter
     * @param queryString
     *          existing query string
     * @param ampersand
     *          string to use for ampersand (e.g. "&" or "&amp;")
     * @param encode
     *          whether to encode value
     * 
     * @return query string (with no leading "?")
     */
    private static StringBuffer append(Object key, Object value, StringBuffer queryString, String ampersand,
            boolean encode) {
        if (queryString.length() > 0) {
            queryString.append(ampersand);
        }

        try {
            if (encode) {
                key = URLEncoder.encode(key.toString(), "UTF-8");
                value = URLEncoder.encode(value.toString(), "UTF-8");
            }
            queryString.append(key);
            queryString.append("=");
            queryString.append(value);
        } catch (UnsupportedEncodingException exception) {
            // do nothing
            ;
        }
        return queryString;
    }
}

Related

1. createQueryString(Map options)
2. createQueryString(Map params)
3. createQueryString(Map params)
4. createQueryStringForParameters(Map parameters)
5. getQuery(Map params, String encode)
6. getQuery(URL theURL)
7. getQueryFromURL(URL url)
8. getQueryMap(String query)