Java tutorial
/* * ==================================================================== * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package com.yoavst.quickapps; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.URI; import java.net.URLDecoder; import java.net.URLEncoder; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Scanner; import org.apache.http.Header; import org.apache.http.HeaderElement; import org.apache.http.HttpEntity; import org.apache.http.NameValuePair; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP; import org.apache.http.util.EntityUtils; /** * A collection of utilities for encoding URLs. */ public class URLEncodedUtils { public static final String CONTENT_TYPE = "application/x-www-form-urlencoded"; private static final String PARAMETER_SEPARATOR = "&"; private static final String NAME_VALUE_SEPARATOR = "="; /** * Returns a list of {@link NameValuePair NameValuePairs} as built from the * URI's query portion. For example, a URI of * http://example.org/path/to/file?a=1&b=2&c=3 would return a list of three * NameValuePairs, one for a=1, one for b=2, and one for c=3. * <p/> * This is typically useful while parsing an HTTP PUT. * * @param uri uri to parse * @param encoding encoding to use while parsing the query */ public static List<NameValuePair> parse(final URI uri, final String encoding) { List<NameValuePair> result = Collections.emptyList(); final String query = uri.getRawQuery(); if (query != null && query.length() > 0) { result = new ArrayList<>(); parse(result, new Scanner(query), encoding); } return result; } /** * Returns a list of {@link NameValuePair NameValuePairs} as parsed from an * {@link HttpEntity}. The encoding is taken from the entity's * Content-Encoding header. * <p/> * This is typically used while parsing an HTTP POST. * * @param entity The entity to parse * @throws IOException If there was an exception getting the entity's data. */ public static List<NameValuePair> parse(final HttpEntity entity) throws IOException { List<NameValuePair> result = Collections.emptyList(); String contentType = null; String charset = null; Header h = entity.getContentType(); if (h != null) { HeaderElement[] elems = h.getElements(); if (elems.length > 0) { HeaderElement elem = elems[0]; contentType = elem.getName(); NameValuePair param = elem.getParameterByName("charset"); if (param != null) { charset = param.getValue(); } } } if (contentType != null && contentType.equalsIgnoreCase(CONTENT_TYPE)) { final String content = EntityUtils.toString(entity, HTTP.ASCII); if (content != null && content.length() > 0) { result = new ArrayList<>(); parse(result, new Scanner(content), charset); } } return result; } /** * Returns true if the entity's Content-Type header is * <code>application/x-www-form-urlencoded</code>. */ public static boolean isEncoded(final HttpEntity entity) { Header h = entity.getContentType(); if (h != null) { HeaderElement[] elems = h.getElements(); if (elems.length > 0) { String contentType = elems[0].getName(); return contentType.equalsIgnoreCase(CONTENT_TYPE); } else { return false; } } else { return false; } } /** * Adds all parameters within the Scanner to the list of * <code>parameters</code>, as encoded by <code>encoding</code>. For * example, a scanner containing the string <code>a=1&b=2&c=3</code> would * add the {@link NameValuePair NameValuePairs} a=1, b=2, and c=3 to the * list of parameters. * * @param parameters List to add parameters to. * @param scanner Input that contains the parameters to parse. * @param encoding Encoding to use when decoding the parameters. */ public static void parse(final List<NameValuePair> parameters, final Scanner scanner, final String encoding) { scanner.useDelimiter(PARAMETER_SEPARATOR); while (scanner.hasNext()) { final String[] nameValue = scanner.next().split(NAME_VALUE_SEPARATOR); if (nameValue.length == 0 || nameValue.length > 2) throw new IllegalArgumentException("bad parameter"); final String name = decode(nameValue[0], encoding); String value = null; if (nameValue.length == 2) value = decode(nameValue[1], encoding); parameters.add(new BasicNameValuePair(name, value)); } } /** * Returns a String that is suitable for use as an <code>application/x-www-form-urlencoded</code> * list of parameters in an HTTP PUT or HTTP POST. * * @param parameters The parameters to include. * @param encoding The encoding to use. */ public static String format(final List<? extends NameValuePair> parameters, final String encoding) { final StringBuilder result = new StringBuilder(); for (final NameValuePair parameter : parameters) { final String encodedName = encode(parameter.getName(), encoding); final String value = parameter.getValue(); final String encodedValue = value != null ? encode(value, encoding) : ""; if (result.length() > 0) result.append(PARAMETER_SEPARATOR); result.append(encodedName); result.append(NAME_VALUE_SEPARATOR); result.append(encodedValue); } return result.toString(); } private static String decode(final String content, final String encoding) { try { return URLDecoder.decode(content, encoding != null ? encoding : HTTP.DEFAULT_CONTENT_CHARSET); } catch (UnsupportedEncodingException problem) { throw new IllegalArgumentException(problem); } } private static String encode(final String content, final String encoding) { try { return URLEncoder.encode(content, encoding != null ? encoding : HTTP.DEFAULT_CONTENT_CHARSET); } catch (UnsupportedEncodingException problem) { throw new IllegalArgumentException(problem); } } }