Java URL Query Parse parseQueryString(final String newQueryString, final String encoding)

Description

Parses a query string into a map

License

Open Source License

Parameter

Parameter	Description
newQueryString	The query string

Return

The map of key value parameters

Declaration

public static Map<String, Deque<String>> parseQueryString(final String newQueryString, final String encoding) 

Method Source Code

//package com.java2s;
/*//  w  w  w.  j  a v a  2s . co m
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.LinkedHashMap;
import java.util.Map;

public class Main {
    /**
     * Parses a query string into a map
     * @param newQueryString The query string
     * @return The map of key value parameters
     */
    @Deprecated
    public static Map<String, Deque<String>> parseQueryString(final String newQueryString) {
        return parseQueryString(newQueryString, null);
    }

    /**
     * Parses a query string into a map
     * @param newQueryString The query string
     * @return The map of key value parameters
     */
    public static Map<String, Deque<String>> parseQueryString(final String newQueryString, final String encoding) {
        Map<String, Deque<String>> newQueryParameters = new LinkedHashMap<>();
        int startPos = 0;
        int equalPos = -1;
        boolean needsDecode = false;
        for (int i = 0; i < newQueryString.length(); ++i) {
            char c = newQueryString.charAt(i);
            if (c == '=' && equalPos == -1) {
                equalPos = i;
            } else if (c == '&') {
                handleQueryParameter(newQueryString, newQueryParameters, startPos, equalPos, i, encoding,
                        needsDecode);
                needsDecode = false;
                startPos = i + 1;
                equalPos = -1;
            } else if ((c == '%' || c == '+') && encoding != null) {
                needsDecode = true;
            }
        }
        if (startPos != newQueryString.length()) {
            handleQueryParameter(newQueryString, newQueryParameters, startPos, equalPos, newQueryString.length(),
                    encoding, needsDecode);
        }
        return newQueryParameters;
    }

    private static void handleQueryParameter(String newQueryString, Map<String, Deque<String>> newQueryParameters,
            int startPos, int equalPos, int i, final String encoding, boolean needsDecode) {
        String key;
        String value = "";
        if (equalPos == -1) {
            key = decodeParam(newQueryString, startPos, i, encoding, needsDecode);
        } else {
            key = decodeParam(newQueryString, startPos, equalPos, encoding, needsDecode);
            value = decodeParam(newQueryString, equalPos + 1, i, encoding, needsDecode);
        }

        Deque<String> queue = newQueryParameters.get(key);
        if (queue == null) {
            newQueryParameters.put(key, queue = new ArrayDeque<>(1));
        }
        if (value != null) {
            queue.add(value);
        }
    }

    private static String decodeParam(String newQueryString, int startPos, int equalPos, String encoding,
            boolean needsDecode) {
        String key;
        if (needsDecode) {
            try {
                key = URLDecoder.decode(newQueryString.substring(startPos, equalPos), encoding);
            } catch (UnsupportedEncodingException e) {
                key = newQueryString.substring(startPos, equalPos);
            }
        } else {
            key = newQueryString.substring(startPos, equalPos);
        }
        return key;
    }
}

Related

1. parseQuery(String query)
2. parseQuery(String query)
3. parseQuery(String queryString)
4. parseQueryParameters( String query)
5. parseQueryParameters( String queryString, String encoding)
6. parseQueryString(String input)
7. parseQueryString(String path)
8. parseQueryString(String path)
9. parseQueryString(String q, String enc)