ASP.NET中XML和JSON互转

ASP.NET中XML和JSON互转

一、XML和JSON字符串的对应表格

1、节点的属性会被对应地转换为JSON对象的成员"attr_name":"attr_value"。如:
 

XML JSON
<xx yy='nn'></xx> { "xx" : { "yy" : "nn" } }
<xx yy=''></xx> { "xx" : { "yy" : "" } }

2、没有子节点、属性和内容的节点被转换为成员"child_name":null

XML JSON
<xx/> { "xx" : null }

3、没有子节点和属性,但是有内容的节点被转换为成员"child_name":"child_text"

XML JSON
<xx>yyy</xx> { "xx" : "yyy" }

4、其它节点和属性会被适当地转换为"child_name":对象或者"child_name":[elements]对象数组,节点的值会被转换为对象成员的"value",如:

XML JSON
<xx yy='nn'><mm>zzz</mm></xx> { "xx" : { "yy" : "nn", "mm" : "zzz" } }
<xx yy='nn'><mm>zzz</mm><mm>aaa</mm></xx> { "xx" : { "yy" : "nn", "mm" : [ "zzz", "aaa" ] } }
<xx><mm>zzz</mm>some text</xx> { "xx" : { "mm" : "zzz", "value" : "some text" } }
<xx value='yyy'>some text<mm>zzz</mm>more text</xx> { "xx" : { "mm" : "zzz", "value" : [ "yyy", "some text", "more text" ] } }

5、字符会被安全地转换为JSON字符串。注意该转换不会保证你的JavaScript代码不会受到任何注入攻击,如果其中的内容来自于一段不安全的XML数据源的话。下面这个例子演示了字符的转义:

XML JSON
<aa>/z'z''z\yyy</aa> { "aa" : "\/z\u0027z\''z\\yyy" }

二、XML转JSON

JSON是一个轻量级的数据交换格式,它可以非常容易地被页面的JavaScript编码为对象的形式,从而方便数据操作。

基于AJAX的页面使用XmlHttpRequest对象从服务端接收数据来响应用户的请求,当返回的数据是XML格式时,它可以被转换为JSON格式的字符串从而通过JavaScript更加容易地对数据进行处理。

许多应用程序都将数据存储为XML的格式,而且会将数据以JSON的格式发送到客户端以做进一步处理。要实现这一点,它们必须将XML格式转换为JSON格式。

XML转JSON代码

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  • C# 代码   复制
  • 
    private static string XmlToJSON(XmlDocument xmlDoc)
    {
        StringBuilder sbJSON = new StringBuilder();
        sbJSON.Append("{ ");
        XmlToJSONnode(sbJSON, xmlDoc.DocumentElement, true);
        sbJSON.Append("}");
        return sbJSON.ToString();
    }
    
    //  XmlToJSONnode:  Output an XmlElement, possibly as part of a higher array
    private static void XmlToJSONnode(StringBuilder sbJSON, XmlElement node, bool showNodeName)
    {
        if (showNodeName)
            sbJSON.Append("\\"" + SafeJSON(node.Name) + "\\": ");
        sbJSON.Append("{");
        // Build a sorted list of key-value pairs
        //  where   key is case-sensitive nodeName
        //          value is an ArrayList of string or XmlElement
        //  so that we know whether the nodeName is an array or not.
        SortedList childNodeNames = new SortedList();
    
        //  Add in all node attributes
        if( node.Attributes!=null)
            foreach (XmlAttribute attr in node.Attributes)
                StoreChildNode(childNodeNames,attr.Name,attr.InnerText);
    
        //  Add in all nodes
        foreach (XmlNode cnode in node.ChildNodes)
        {
            if (cnode is XmlText)
                StoreChildNode(childNodeNames, "value", cnode.InnerText);
            else if (cnode is XmlElement)
                StoreChildNode(childNodeNames, cnode.Name, cnode);
        }
    
        // Now output all stored info
        foreach (string childname in childNodeNames.Keys)
        {
            ArrayList alChild = (ArrayList)childNodeNames[childname];
            if (alChild.Count == 1)
                OutputNode(childname, alChild[0], sbJSON, true);
            else
            {
                sbJSON.Append(" \\"" + SafeJSON(childname) + "\\": [ ");
                foreach (object Child in alChild)
                    OutputNode(childname, Child, sbJSON, false);
                sbJSON.Remove(sbJSON.Length - 2, 2);
                sbJSON.Append(" ], ");
            }
        }
        sbJSON.Remove(sbJSON.Length - 2, 2);
        sbJSON.Append(" }");
    }
    
    //  StoreChildNode: Store data associated with each nodeName
    //                  so that we know whether the nodeName is an array or not.
    private static void StoreChildNode(SortedList childNodeNames, string nodeName, object nodeValue)
    {
        // Pre-process contraction of XmlElement-s
        if (nodeValue is XmlElement)
        {
            // Convert  <aa></aa> into "aa":null
            //          <aa>xx</aa> into "aa":"xx"
            XmlNode cnode = (XmlNode)nodeValue;
            if( cnode.Attributes.Count == 0)
            {
                XmlNodeList children = cnode.ChildNodes;
                if( children.Count==0)
                    nodeValue = null;
                else if (children.Count == 1 && (children[0] is XmlText))
                    nodeValue = ((XmlText)(children[0])).InnerText;
            }
        }
        // Add nodeValue to ArrayList associated with each nodeName
        // If nodeName doesn't exist then add it
        object oValuesAL = childNodeNames[nodeName];
        ArrayList ValuesAL;
        if (oValuesAL == null)
        {
            ValuesAL = new ArrayList();
            childNodeNames[nodeName] = ValuesAL;
        }
        else
            ValuesAL = (ArrayList)oValuesAL;
        ValuesAL.Add(nodeValue);
    }
    
    private static void OutputNode(string childname, object alChild, StringBuilder sbJSON, bool showNodeName)
    {
        if (alChild == null)
        {
            if (showNodeName)
                sbJSON.Append("\\"" + SafeJSON(childname) + "\\": ");
            sbJSON.Append("null");
        }
        else if (alChild is string)
        {
            if (showNodeName)
                sbJSON.Append("\\"" + SafeJSON(childname) + "\\": ");
            string sChild = (string)alChild;
            sChild = sChild.Trim();
            sbJSON.Append("\\"" + SafeJSON(sChild) + "\\"");
        }
        else
            XmlToJSONnode(sbJSON, (XmlElement)alChild, showNodeName);
        sbJSON.Append(", ");
    }
    
    // Make a string safe for JSON
    private static string SafeJSON(string sIn)
    {
        StringBuilder sbOut = new StringBuilder(sIn.Length);
        foreach (char ch in sIn)
        {
            if (Char.IsControl(ch) || ch == '\\'')
            {
                int ich = (int)ch;
                sbOut.Append(@"\\u" + ich.ToString("x4"));
                continue;
            }
            else if (ch == '\\"' || ch == '\\\\' || ch == '/')
            {
                sbOut.Append('\\\\');
            }
            sbOut.Append(ch);
        }
        return sbOut.ToString();
    }
    
    		
  • 三、JSON格式转换为XML格式

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  • C# 代码   复制
  • 
    /// <summary>
            /// json字符串转换为Xml对象
            /// </summary>
            /// <param name="sJson"></param>
            /// <returns></returns>
            public static XmlDocument Json2Xml(string sJson)
            {
                //XmlDictionaryReader reader = JsonReaderWriterFactory.CreateJsonReader(Encoding.UTF8.GetBytes(sJson), XmlDictionaryReaderQuotas.Max);
                //XmlDocument doc = new XmlDocument();
                //doc.Load(reader);
    
                JavaScriptSerializer oSerializer = new JavaScriptSerializer();
                Dictionary<string, object> Dic = (Dictionary<string, object>)oSerializer.DeserializeObject(sJson);
                XmlDocument doc = new XmlDocument();
                XmlDeclaration xmlDec;
                xmlDec = doc.CreateXmlDeclaration("1.0", "gb2312", "yes");
                doc.InsertBefore(xmlDec, doc.DocumentElement);
                XmlElement nRoot = doc.CreateElement("root");
                doc.AppendChild(nRoot);
                foreach (KeyValuePair<string, object> item in Dic)
                {
                    XmlElement element = doc.CreateElement(item.Key);
                    KeyValue2Xml(element, item);
                    nRoot.AppendChild(element);
                }
                return doc;
            }
    
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