聊天服务器-解密陌生人（9）聊天消息转发

提示： 因为工程稍微有点大对我个人来说，所以可能在某些方面讲的不清楚或逻辑性不够强，如果有问题请@我。
原工程：https://github.com/LineChen/

五、转发信息
因为客户端和服务器是保持长连接的，所以可以根据用户Id得到用户的会话session，得到session就可以发送消息。
对于聊天，主要分聊天双方都在线和一方离线的情况。都在线的情况好办，直接转发；一方离线时，需要在数据库中保存离线消息，等到离线好友登录时会发送给ta。保存离线消息需要注意的是，要根据消息类型做相应的处理（文本消息、语音消息、图片消息）。
/**
* 发送信息给单个用户
*
* @param moMoMsg
* @param getterId
*/
private void sendMsgToUser(iMoMoMsg moMoMsg, String getterId) {
if (ManageClientSession.isContainsId(getterId)) {
ManageClientSession.getSession(getterId).write(moMoMsg);
// System.out.println(“转发成功..”);
} else {
SqlModel model = new SqlModel();
if (!model.isTableExists(“mc_” + getterId))// “mc_” + userId
model.createCacheTable(getterId);// 创建缓存数据库
MsgDb msgDb = MsgTranceUtil.getInstance().Trance_Net2Db(moMoMsg);
if (model.insertCacheMsg(msgDb, getterId)) {
// System.out.println(“缓存成功”);
} else {
// System.out.println(“缓存失败”);
}
}
}

下面是存储在数据库的离线消息和发送的消息转化类：
package com.imomo_msg;

import java.text.SimpleDateFormat;
import java.util.Date;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.server_utils.FileTools;
import com.server_utils.StaticValues;

/**
* 消息包转换工具
*
* @author Administrator
*
*/
public class MsgTranceUtil {

public static MsgTranceUtil getInstance() {return new MsgTranceUtil();
}/*** 数据库存数消息转化为网络传输消息* * @param msgDb* @return*/
public iMoMoMsg Trance_Db2Net(MsgDb msgDb) {iMoMoMsg moMsg = new iMoMoMsg();switch (msgDb.msgType) {case iMoMoMsgTypes.CHATING_TEXT_MSG:moMsg.symbol = '+';moMsg.msgJson = msgDb.msgJson;break;case iMoMoMsgTypes.CHATING_IMAGE_MSG:JSONObject json = JSON.parseObject(msgDb.msgJson);moMsg.symbol = '-';String imagePath = json.getString(MsgKeys.imagePath);moMsg.msgBytes = FileTools.getInstance().getMultyFileBytes(imagePath);json.remove(MsgKeys.imagePath);moMsg.msgJson = json.toJSONString();//删除本地缓存图片FileTools.getInstance().deleteFile(imagePath);break;case iMoMoMsgTypes.CHATING_VOICE_MSG:moMsg.symbol = '-';JSONObject json2 = JSON.parseObject(msgDb.msgJson);String voicePath = json2.getString(MsgKeys.voicePath);moMsg.msgBytes = FileTools.getInstance().getMultyFileBytes(voicePath);json2.remove(MsgKeys.voicePath);moMsg.msgJson = json2.toJSONString();FileTools.getInstance().deleteFile(voicePath);break;case iMoMoMsgTypes.ADD_FRIEND:moMsg.symbol = '+';moMsg.msgJson = msgDb.msgJson;break;case iMoMoMsgTypes.RESET_HEAD:JSONObject resetHeadjson = JSON.parseObject(msgDb.msgJson);moMsg.symbol = '-';String headPath = resetHeadjson.getString(MsgKeys.imagePath);moMsg.msgBytes = FileTools.getInstance().getMultyFileBytes(headPath);resetHeadjson.remove(MsgKeys.imagePath);moMsg.msgJson = resetHeadjson.toJSONString();//删除本地缓存图片FileTools.getInstance().deleteFile(headPath);break;}return moMsg;
}/*** 网络消息转化为数据库存储消息* * @param moMsg* @return*/
public MsgDb Trance_Net2Db(iMoMoMsg moMsg) {MsgDb msgDb = new MsgDb();JSONObject json = JSON.parseObject(moMsg.msgJson);int msgtype = json.getIntValue(MsgKeys.msgType);switch (msgtype) {case iMoMoMsgTypes.CHATING_TEXT_MSG:break;case iMoMoMsgTypes.CHATING_IMAGE_MSG:String imagePath = StaticValues.MSG_CACHE_IMA_P_PATH+ json.getString(MsgKeys.userId) + "_"+ System.currentTimeMillis() + ".png";FileTools.getInstance().saveMultyFile(imagePath, moMsg.msgBytes);json.put(MsgKeys.imagePath, imagePath);break;case iMoMoMsgTypes.CHATING_VOICE_MSG:String voicePath = StaticValues.MSG_CACHE_VOI_P_PATH+ json.getString(MsgKeys.userId) + "_"+ System.currentTimeMillis() + ".amr";FileTools.getInstance().saveMultyFile(voicePath, moMsg.msgBytes);json.put(MsgKeys.voicePath, voicePath);break;case iMoMoMsgTypes.ADD_FRIEND:

// String headPath = StaticValues.HEAD_P_PATH
// + json.getString(MsgKeys.userId) + “.png”;
// json.put(MsgKeys.imagePath, headPath);
break;

    case iMoMoMsgTypes.RESET_HEAD:String headPath = StaticValues.MSG_CACHE_IMA_P_PATH+ json.getString(MsgKeys.userId) + "_"+ System.currentTimeMillis() + ".png";FileTools.getInstance().saveMultyFile(headPath, moMsg.msgBytes);json.put(MsgKeys.imagePath, headPath);break;}msgDb.msgType = msgtype;msgDb.msgJson = json.toJSONString();return msgDb;
}

}

然后是转发离线消息:
/**
* 转发离线消息
*
* @param session
* @param userId
* @param model
*/
private void sendCacheMsg(IoSession session, String userId, SqlModel model) {
if (model.isTableExists(“mc_” + userId)) {
if (model.getMsgCount(userId) > 0) {
// 说明有离线消息
List list = model.getCacheMsgs(userId);
for (MsgDb msgDb : list) {
iMoMoMsg moMsg = MsgTranceUtil.getInstance().Trance_Db2Net(
msgDb);

                session.write(moMsg);}// 清空数据库离线文件model.clearMsgCache(userId);}}
}