XMPP实现群聊截图(spark+openfire)

spark默认的单聊截图模式是利用文件来来进行传递，调用SparkTransferManager.getInstance().sendFile(img.getTmpFile(), getParticipantJID());

调用    final OutgoingFileTransfer transfer = transferManager
                .createOutgoingFileTransfer(fullJID);

通过    transfer.sendFile(file, "Sending file");来进行发送。

 

spark的群聊(临时会议基础上进行改造)却不能使用这种模式来进行文件传递，缺少了文件传递的JID。由此，想出一种简单的方式来通过xmpp来进行传递。

思路很简单：截图后的图片保存到本地，插入到聊天显示框，将图片image转为byte数组，再转为hex存储到String中（自定义标签,如<img>来将转码后的内容保存，方便接受时候截取），利用Message传递时setBody(“转码后的字符串”)。

在群聊接收消息的GroupChatRoom的handleMessagePacket方法进行修改，创建BufferedImag并利用ImageIo将图片写入到指定文件中，具体代码如下：

public void sendMessage() {
		String text = getChatInputEditor().getText();
	    StringBuffer sb = new StringBuffer();
        String  imageByte=null;
	       final StringTokenizer tokenizer = new StringTokenizer(text, " \n \t", true);
	        while (tokenizer.hasMoreTokens()) {
	            String textFound = tokenizer.nextToken();
	            if(textFound.startsWith("Tmp://")) {
	                String tmpPath = textFound.substring(textFound.indexOf("Tmp://") + 6, textFound.indexOf("#"));
	                Log.debug("screen shot file " + tmpPath + "created.");

	                //CHECK IF SEND BY ME, JUST INSERT EXISTED ICON IF TRUE
	                File rootPath =  new File(Spark.getSparkUserHome(), "/tempImages");//本地创建截图
	                File f = new File(rootPath.getAbsolutePath(), tmpPath);
	            
	                if(f.exists()){
	                	try {
							imageByte=image2String(f);//得到转码后的字符串
						} catch (Exception e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
//	                  String s = new String (imageByte);
	                	sb.append("<img>");
	                	sb.append(imageByte);
	                	sb.append("</img>");
	                }
//	                RevImage image = new RevImage();
//	                insertComponent(image);
	            }
	        }
			sendMessage(text+sb.toString());
		
	}

 转码的具体实现：

	public static  String image2String(File f) throws Exception {
		FileInputStream fis = new FileInputStream( f );
		byte[] bytes = new byte[fis.available()];
		fis.read(bytes);
		fis.close();
		
		// 生成字符串
		String imgStr = byte2hex( bytes );
		return imgStr;
	
	}

	private static String byte2hex(byte[] b) {
		  StringBuffer sb = new StringBuffer();
		   String stmp = "";
		   for (int n = 0; n < b.length; n++) {
		    stmp = Integer.toHexString(b[n] & 0XFF);
		    if (stmp.length() == 1){
		    	sb.append("0" + stmp);
		    }else{
		    	sb.append(stmp);
		    }
		    
		   }
		   return sb.toString();
	}

 收到消息后的处理：

if(message.getBody().contains("Tmp://")&&message.getBody().contains("<img>")&&message.getBody().contains("</img>")){
						final StringTokenizer tokenizer = new StringTokenizer(message.getBody(), " \n \t", true);
						 byte[] imgbyte=null;
						   ImageIcon icon=null;
						   File f=null;
					    while (tokenizer.hasMoreTokens()) {
					        String textFound = tokenizer.nextToken();
					    	   if(textFound.startsWith("Tmp://")) {
					                String tmpPath = textFound.substring(textFound.indexOf("Tmp://") + 6, textFound.indexOf("#"));
					                Log.debug("screen shot file " + tmpPath + "created.");

					                //CHECK IF SEND BY ME, JUST INSERT EXISTED ICON IF TRUE
					                File rootPath =  new File(Spark.getSparkUserHome(), "/tempImages");
					               f = new File(rootPath.getAbsolutePath(), tmpPath);
					                if(!f.exists()){
					                 try {
										f.createNewFile();
									} catch (IOException e) {
										// TODO Auto-generated catch block
										e.printStackTrace();
									}
					                }
					    }
					    	   if(textFound.contains("<img>")&&textFound.contains("</img>")){
					            	imgbyte = hex2byte(textFound);
					                byte[] bytes =imgbyte;
					                if (bytes != null && bytes.length > 0) {
					                   icon = new ImageIcon(bytes);
					                }
					                Image image =icon.getImage();
					                BufferedImage bufImg = new BufferedImage(image.getWidth(null), image.getHeight(null),BufferedImage.TYPE_INT_RGB);  
					                Graphics g = bufImg .createGraphics();  
					                g.drawImage(image, 0, 0, null);  
					                g.dispose();

					            	try {
										ImageIO.write(bufImg, "PNG", new FileOutputStream(f));
									} catch (IOException e) {
										// TODO Auto-generated catch block
										e.printStackTrace();
									}
					            }
					    }
					    getTranscriptWindow().insertMessage(from, message,
					    		getColor(from),
					    		getMessageBackground(from, message.getBody()));

 解码代码：

    private byte[] hex2byte(String textFound) {
    	int start = textFound.indexOf("<img>")+5;
    	int end = textFound.indexOf("</img>");
    	String str = textFound.substring(start, end);
    	  if (str == null)
    		     return null;
    		    str = str.trim();
    		    int len = str.length();
    		    if (len == 0 || len % 2 == 1)
    		     return null;
    		    byte[] b = new byte[len / 2];
    		    try {
    		     for (int i = 0; i < str.length(); i += 2) {
    		      b[i / 2] = (byte) Integer.decode("0X" + str.substring(i, i + 2)).intValue();
    		     }
    		     return b;
    		    } catch (Exception e) {
    		     return null;
    		    }
	}

 这样，通过byte数组来生成图片，实现群聊截图功能。