Android modifies XML files

Source: Internet
Author: User

XML needs to be used to record data in recent projects. There are few articles on the Internet.


/*** Append content to the XML document * @ param instructions * @ throws ParserConfigurationException * @ throws SAXException * @ throws IOException * @ throws TransformerException */public void append2XML (String instructions) throws ParserConfigurationException, SAXException, IOException, TransformerException {Long st = System. currentTimeMillis (); String time = DateUtils. getCurrLongTime (); DocumentBuilderFactory dbf = DocumentBui LderFactory. newInstance (); // construct DocumentBuilder db = dbf through an instance. newDocumentBuilder (); // create a Document to parse the specified Document doc = db. parse (getInputStream (); // doc = db. newDocument (); // Add an Element eModel = doc. createElement ("instructionsModel"); Element eInstructions ctions = doc. createElement ("instructions"); Element eCreatetime = doc. createElement ("createtime"); Element eLastUseTime = doc. creat EElement ("lastusetime"); // Add Text textInstructions = doc to the element. createTextNode (instructions); Text textCreatetime = doc. createTextNode (time); Text textLastUseTime = doc. createTextNode (time); eInstructions. appendChild (textInstructions); eCreatetime. appendChild (textCreatetime); elestusetime. appendChild (textLastUseTime); // obtain the eModel Of The 0th nodes of the node by Name. appendChild (eInstructions); eModel. appendChild (eCreate Time); eModel. appendChild (eLastUseTime); Node book = doc. getElementsByTagName ("instructionsList "). item (0); book. appendChild (eModel); // Add an attribute // Attr attr = doc. createAttribute ("aaa"); // create the factory object TransformerFactory tfs = TransformerFactory. newInstance (); // create the Transformer object Transformer tf = tfs. newTransformer (); // output the document to the output stream. Tf. transform (new DOMSource (doc), new StreamResult (new FileOutputStream (fu. getSDCardRoot () + File. separator + filePath + File. separator + "bb. xml "); Long hastime = System. currentTimeMillis ()-st; Log. I (TAG, "DOM mode time consumption:" + hastime );}


I checked it online for a long time. It seems that everyone agrees that PULL can only Parse XML and cannot modify XML files.

So I thought of a very troublesome modification method.

1. parse the original XML file to obtain the data set.

2. Insert new data into the collection

3. regenerate XML

The Code is as follows:

1. parse XML files

/*** Get all the instruction information in XML *** @ Param inputstream * @ return * @ throws xmlpullparserexception * @ throws ioexception */private list <instructions> parsedatesource (inputstream) throws xmlpullparserexception, ioexception {long St = system. currenttimemillis (); List <instructions> instructionslist = NULL; instructions instructionsmodel = NULL; xmlpullparser parse = xml. newpullparser (); parse. setinput (inputst Ream, "UTF-8"); int event = parse. geteventtype (); While (event! = Xmlpullparser. end_document) {Switch (event) {Case xmlpullparser. start_document: instructionslist = new arraylist <instructions> (); // initialize the command set break; Case xmlpullparser. start_tag: If (PARSE. getname (). equals ("instructionsmodel") {instructionsmodel = new instructions ctions ();} If (instructionsmodel! = NULL) {If (PARSE. getname (). equals ("Instructions") {instructionsmodel. setinstructions (PARSE. nexttext ();} else if (PARSE. getname (). equals ("createtime") {instructionsmodel. setcreatetime (PARSE. nexttext ();} else if (PARSE. getname (). equals ("lastusetime") {instructionsmodel. setlastusetime (PARSE. nexttext () ;}} break; Case xmlpullparser. end_tag: If (PARSE. getname (). equals ("instructionsmodel") {instructionslist. add (instructionsmodel); instructionsmodel = NULL;} break; default: break;} event = parse. next (); // enter the next element and trigger the corresponding event} Long hastime = system. currenttimemillis ()-ST; log. I (TAG, "Time consumed for pull parsing:" + hastime); Return instructionslist ;}

2. Insert data into the set

/*** Add the new command to the XML file * @ Param out * @ Param inputstream * @ Param instructions2 * @ throws illegalstateexception * @ throws illegalargumentexception * @ throws xmlpullparserexception * @ throws ioexception */private void append2xml (outputstream out, list <instructions> instructionslist, instructions instructions2) throws failed, illegalstateexception, ioexception, xmlpullparserexception {// avoid record command operation for (INT I = 0; I <instructionslist. size (); I ++) {instructions = instructionslist. get (I); If (instructions. getinstructions (). equals (instructions2.getinstructions () {instructionslist. remove (I); instructions2.setcreatetime (instructions. getcreatetime (); break;} instructionslist. add (0, instructions2); createinstructionxml (Out, instructionslist );}

3. How to generate a new XML file

/*** Generate an XML file based on the list * @ param out * @ param instructionsList * @ throws IllegalArgumentException * @ throws IllegalStateException * @ throws IOException */private void createInstructionXml (OutputStream out, list <Instructions> instructionsList) throws IllegalArgumentException, IllegalStateException, IOException {// TODO Auto-generated method stubXmlSerializer serializer = Xml. newSerializer (); // sets the file encoding serializer. setOutput (out, "UTF-8"); serializer. startDocument ("UTF-8", true); serializer. startTag (null, "instructionsList"); for (Instructions instructions: instructionsList) {serializer. startTag (null, "instructionsModel"); serializer. startTag (null, "instructions"); serializer. text (instructions. getInstructions (); serializer. endTag (null, "instructions"); serializer. startTag (null, "createtime"); serializer. text (instructions. getCreateTime (); serializer. endTag (null, "createtime"); serializer. startTag (null, "lastusetime"); serializer. text (instructions. getLastUseTime (); serializer. endTag (null, "lastusetime"); serializer. endTag (null, "instructionsModel");} serializer. endTag (null, "instructionsList"); serializer. endDocument (); out. flush (); out. close ();}

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