任意对象转化为JSON

  import java.beans.IntrospectionException;
    import java.beans.Introspector;
    import java.beans.PropertyDescriptor;
    import java.math.BigDecimal;
    import java.math.BigInteger;
    import java.util.List;
    import java.util.Map;
    import java.util.Set;
    /**
     * 序列化对象为JSON格式 遵循JSON组织公布标准
     *
     * @date 2008/05/07
     * @version 1.0.0
     */
    public class Json {
        /** Commons Logging instance. */
        private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog(Json. class );
        /**
         * @param obj 任意对象
         * @return String
         */
        public static String object2json(Object obj) {
            StringBuilder json = new StringBuilder();
            if (obj == null ) {
                json.append( " /"/" " );
            } else if (obj instanceof String || obj instanceof Integer || obj instanceof Float || obj instanceof Boolean
                    || obj instanceof Short || obj instanceof Double || obj instanceof Long || obj instanceof BigDecimal
                    || obj instanceof BigInteger || obj instanceof Byte) {
                json.append( " /" " ).append(string2json(obj.toString())).append( " /" " );
            } else if (obj instanceof Object[]) {
                json.append(array2json((Object[]) obj));
            } else if (obj instanceof List) {
                json.append(list2json((List <?> ) obj));
            } else if (obj instanceof Map) {
                json.append(map2json((Map <? , ?> ) obj));
            } else if (obj instanceof Set) {
                json.append(set2json((Set <?> ) obj));
            } else {
                json.append(bean2json(obj));
            }
            return json.toString();
        }
        /**
         * @param bean bean对象
         * @return String
         */
        public static String bean2json(Object bean) {
            StringBuilder json = new StringBuilder();
            json.append( " { " );
            PropertyDescriptor[] props = null ;
            try {
                props = Introspector.getBeanInfo(bean.getClass(), Object. class ).getPropertyDescriptors();
            } catch (IntrospectionException e) {
            }
            if (props != null ) {
                for ( int i = 0 ; i < props.length; i ++ ) {
                    try {
                        String name = object2json(props[i].getName());
                        String value = object2json(props[i].getReadMethod().invoke(bean));
                        json.append(name);
                        json.append( " : " );
                        json.append(value);
                        json.append( " , " );
                    } catch (Exception e) {
                    }
                }
                json.setCharAt(json.length() - 1 , ' } ' );
            } else {
                json.append( " } " );
            }
            return json.toString();
        }
        /**
         * @param list list对象
         * @return String
         */
        public static String list2json(List <?> list) {
            StringBuilder json = new StringBuilder();
            json.append( " [ " );
            if (list != null && list.size() > 0 ) {
                for (Object obj : list) {
                    json.append(object2json(obj));
                    json.append( " , " );
                }
                json.setCharAt(json.length() - 1 , ' ] ' );
            } else {
                json.append( " ] " );
            }
            return json.toString();
        }
        /**
         * @param array 对象数组
         * @return String
         */
        public static String array2json(Object[] array) {
            StringBuilder json = new StringBuilder();
            json.append( " [ " );
            if (array != null && array.length > 0 ) {
                for (Object obj : array) {
                    json.append(object2json(obj));
                    json.append( " , " );
                }
                json.setCharAt(json.length() - 1 , ' ] ' );
            } else {
                json.append( " ] " );
            }
            return json.toString();
        }
        /**
         * @param map map对象
         * @return String
         */
        public static String map2json(Map <? , ?> map) {
            StringBuilder json = new StringBuilder();
            json.append( " { " );
            if (map != null && map.size() > 0 ) {
                for (Object key : map.keySet()) {
                    json.append(object2json(key));
                    json.append( " : " );
                    json.append(object2json(map.get(key)));
                    json.append( " , " );
                }
                json.setCharAt(json.length() - 1 , ' } ' );
            } else {
                json.append( " } " );
            }
            return json.toString();
        }
        /**
         * @param set 集合对象
         * @return String
         */
        public static String set2json(Set <?> set) {
            StringBuilder json = new StringBuilder();
            json.append( " [ " );
            if (set != null && set.size() > 0 ) {
                for (Object obj : set) {
                    json.append(object2json(obj));
                    json.append( " , " );
                }
                json.setCharAt(json.length() - 1 , ' ] ' );
            } else {
                json.append( " ] " );
            }
            return json.toString();
        }
        /**
         * @param s 参数
         * @return String
         */
        public static String string2json(String s) {
            if (s == null )
                return "" ;
            StringBuilder sb = new StringBuilder();
            for ( int i = 0 ; i < s.length(); i ++ ) {
                char ch = s.charAt(i);
                switch (ch) {
                case ' " ' :
                    sb.append( " ///" " );
                    break ;
                case ' // ' :
                    sb.append( " //// " );
                    break ;
                case ' /b ' :
                    sb.append( " //b " );
                    break ;
                case ' /f ' :
                    sb.append( " //f " );
                    break ;
                case ' /n ' :
                    sb.append( " //n " );
                    break ;
                case ' /r ' :
                    sb.append( " //r " );
                    break ;
                case ' /t ' :
                    sb.append( " //t " );
                    break ;
                case ' / ' :
                    sb.append( " /// " );
                    break ;
                default :
                    if (ch >= ' /u0000 ' && ch <= ' /u001F ' ) {
                        String ss = Integer.toHexString(ch);
                        sb.append( " //u " );
                        for ( int k = 0 ; k < 4 - ss.length(); k ++ ) {
                            sb.append( ' 0 ' );
                        }
                        sb.append(ss.toUpperCase());
                    } else {
                        sb.append(ch);
                    }
                }
            }
            return sb.toString();
        }
    }