Java tutorial
package org.json; /* Copyright (c) 2015 JSON.org Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. The Software shall be used for Good, not Evil. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ import java.util.Iterator; /** * This provides static methods to convert an XML text into a JSONObject, and to * covert a JSONObject into an XML text. * * @author JSON.org * @version 2016-01-01 */ @SuppressWarnings("boxing") public class XML { /** The Character '&'. */ public static final Character AMP = '&'; /** The Character '''. */ public static final Character APOS = '\''; /** The Character '!'. */ public static final Character BANG = '!'; /** The Character '='. */ public static final Character EQ = '='; /** The Character '>'. */ public static final Character GT = '>'; /** The Character '<'. */ public static final Character LT = '<'; /** The Character '?'. */ public static final Character QUEST = '?'; /** The Character '"'. */ public static final Character QUOT = '"'; /** The Character '/'. */ public static final Character SLASH = '/'; /** * Replace special characters with XML escapes: * * <pre> * & <small>(ampersand)</small> is replaced by &amp; * < <small>(less than)</small> is replaced by &lt; * > <small>(greater than)</small> is replaced by &gt; * " <small>(double quote)</small> is replaced by &quot; * </pre> * * @param string * The string to be escaped. * @return The escaped string. */ public static String escape(String string) { StringBuilder sb = new StringBuilder(string.length()); for (int i = 0, length = string.length(); i < length; i++) { char c = string.charAt(i); switch (c) { case '&': sb.append("&"); break; case '<': sb.append("<"); break; case '>': sb.append(">"); break; case '"': sb.append("""); break; case '\'': sb.append("'"); break; default: sb.append(c); } } return sb.toString(); } /** * Throw an exception if the string contains whitespace. Whitespace is not * allowed in tagNames and attributes. * * @param string * A string. * @throws JSONException */ public static void noSpace(String string) throws JSONException { int i, length = string.length(); if (length == 0) { throw new JSONException("Empty string."); } for (i = 0; i < length; i += 1) { if (Character.isWhitespace(string.charAt(i))) { throw new JSONException("'" + string + "' contains a space character."); } } } /** * Scan the content following the named tag, attaching it to the context. * * @param x * The XMLTokener containing the source string. * @param context * The JSONObject that will include the new material. * @param name * The tag name. * @return true if the close tag is processed. * @throws JSONException */ private static boolean parse(XMLTokener x, JSONObject context, String name) throws JSONException { char c; int i; JSONObject jsonobject = null; String string; String tagName; Object token; // Test for and skip past these forms: // <!-- ... --> // <! ... > // <![ ... ]]> // <? ... ?> // Report errors for these forms: // <> // <= // << token = x.nextToken(); // <! if (token == BANG) { c = x.next(); if (c == '-') { if (x.next() == '-') { x.skipPast("-->"); return false; } x.back(); } else if (c == '[') { token = x.nextToken(); if ("CDATA".equals(token)) { if (x.next() == '[') { string = x.nextCDATA(); if (string.length() > 0) { context.accumulate("content", string); } return false; } } throw x.syntaxError("Expected 'CDATA['"); } i = 1; do { token = x.nextMeta(); if (token == null) { throw x.syntaxError("Missing '>' after '<!'."); } else if (token == LT) { i += 1; } else if (token == GT) { i -= 1; } } while (i > 0); return false; } else if (token == QUEST) { // <? x.skipPast("?>"); return false; } else if (token == SLASH) { // Close tag </ token = x.nextToken(); if (name == null) { throw x.syntaxError("Mismatched close tag " + token); } if (!token.equals(name)) { throw x.syntaxError("Mismatched " + name + " and " + token); } if (x.nextToken() != GT) { throw x.syntaxError("Misshaped close tag"); } return true; } else if (token instanceof Character) { throw x.syntaxError("Misshaped tag"); // Open tag < } else { tagName = (String) token; token = null; jsonobject = new JSONObject(); for (;;) { if (token == null) { token = x.nextToken(); } // attribute = value if (token instanceof String) { string = (String) token; token = x.nextToken(); if (token == EQ) { token = x.nextToken(); if (!(token instanceof String)) { throw x.syntaxError("Missing value"); } jsonobject.accumulate(string, XML.stringToValue((String) token)); token = null; } else { jsonobject.accumulate(string, ""); } } else if (token == SLASH) { // Empty tag <.../> if (x.nextToken() != GT) { throw x.syntaxError("Misshaped tag"); } if (jsonobject.length() > 0) { context.accumulate(tagName, jsonobject); } else { context.accumulate(tagName, ""); } return false; } else if (token == GT) { // Content, between <...> and </...> for (;;) { token = x.nextContent(); if (token == null) { if (tagName != null) { throw x.syntaxError("Unclosed tag " + tagName); } return false; } else if (token instanceof String) { string = (String) token; if (string.length() > 0) { jsonobject.accumulate("content", XML.stringToValue(string)); } } else if (token == LT) { // Nested element if (parse(x, jsonobject, tagName)) { if (jsonobject.length() == 0) { context.accumulate(tagName, ""); } else if (jsonobject.length() == 1 && jsonobject.opt("content") != null) { context.accumulate(tagName, jsonobject.opt("content")); } else { context.accumulate(tagName, jsonobject); } return false; } } } } else { throw x.syntaxError("Misshaped tag"); } } } } /** * Try to convert a string into a number, boolean, or null. If the string * can't be converted, return the string. This is much less ambitious than * JSONObject.stringToValue, especially because it does not attempt to * convert plus forms, octal forms, hex forms, or E forms lacking decimal * points. * * @param string * A String. * @return A simple JSON value. */ public static Object stringToValue(String string) { if ("true".equalsIgnoreCase(string)) { return Boolean.TRUE; } if ("false".equalsIgnoreCase(string)) { return Boolean.FALSE; } if ("null".equalsIgnoreCase(string)) { return JSONObject.NULL; } // If it might be a number, try converting it, first as a Long, and then // as a Double. If that doesn't work, return the string. try { char initial = string.charAt(0); if (initial == '-' || (initial >= '0' && initial <= '9')) { Long value = new Long(string); if (value.toString().equals(string)) { return value; } } } catch (Exception ignore) { try { Double value = new Double(string); if (value.toString().equals(string)) { return value; } } catch (Exception ignoreAlso) { } } return string; } /** * Convert a well-formed (but not necessarily valid) XML string into a * JSONObject. Some information may be lost in this transformation because * JSON is a data format and XML is a document format. XML uses elements, * attributes, and content text, while JSON uses unordered collections of * name/value pairs and arrays of values. JSON does not does not like to * distinguish between elements and attributes. Sequences of similar * elements are represented as JSONArrays. Content text may be placed in a * "content" member. Comments, prologs, DTDs, and <code><[ [ ]]></code> * are ignored. * * @param string * The source string. * @return A JSONObject containing the structured data from the XML string. * @throws JSONException */ public static JSONObject toJSONObject(String string) throws JSONException { JSONObject jo = new JSONObject(); XMLTokener x = new XMLTokener(string); while (x.more() && x.skipPast("<")) { parse(x, jo, null); } return jo; } /** * Convert a JSONObject into a well-formed, element-normal XML string. * * @param object * A JSONObject. * @return A string. * @throws JSONException */ public static String toString(Object object) throws JSONException { return toString(object, null); } /** * Convert a JSONObject into a well-formed, element-normal XML string. * * @param object * A JSONObject. * @param tagName * The optional name of the enclosing tag. * @return A string. * @throws JSONException */ public static String toString(Object object, String tagName) throws JSONException { StringBuilder sb = new StringBuilder(); JSONArray ja; JSONObject jo; String key; Iterator<String> keys; String string; Object value; if (object instanceof JSONObject) { // Emit <tagName> if (tagName != null) { sb.append('<'); sb.append(tagName); sb.append('>'); } // Loop thru the keys. jo = (JSONObject) object; keys = jo.keys(); while (keys.hasNext()) { key = keys.next(); value = jo.opt(key); if (value == null) { value = ""; } else if (value.getClass().isArray()) { value = new JSONArray(value); } string = value instanceof String ? (String) value : null; // Emit content in body if ("content".equals(key)) { if (value instanceof JSONArray) { ja = (JSONArray) value; int i = 0; for (Object val : ja) { if (i > 0) { sb.append('\n'); } sb.append(escape(val.toString())); i++; } } else { sb.append(escape(value.toString())); } // Emit an array of similar keys } else if (value instanceof JSONArray) { ja = (JSONArray) value; for (Object val : ja) { if (val instanceof JSONArray) { sb.append('<'); sb.append(key); sb.append('>'); sb.append(toString(val)); sb.append("</"); sb.append(key); sb.append('>'); } else { sb.append(toString(val, key)); } } } else if ("".equals(value)) { sb.append('<'); sb.append(key); sb.append("/>"); // Emit a new tag <k> } else { sb.append(toString(value, key)); } } if (tagName != null) { // Emit the </tagname> close tag sb.append("</"); sb.append(tagName); sb.append('>'); } return sb.toString(); } if (object != null) { if (object.getClass().isArray()) { object = new JSONArray(object); } if (object instanceof JSONArray) { ja = (JSONArray) object; for (Object val : ja) { // XML does not have good support for arrays. If an array // appears in a place where XML is lacking, synthesize an // <array> element. sb.append(toString(val, tagName == null ? "array" : tagName)); } return sb.toString(); } } string = (object == null) ? "null" : escape(object.toString()); return (tagName == null) ? "\"" + string + "\"" : (string.length() == 0) ? "<" + tagName + "/>" : "<" + tagName + ">" + string + "</" + tagName + ">"; } }