App的前后台数据同步

前言

在开发一个点餐软件时，app的订单数据是使用本地Sqlite数据库，在提交订单数据后，当订单数据在后台（Mysql数据库）发生变化时（如：已买单），本地数据如何改变呢？

思路

前台在查询时，将后台订单数据以数组方式发送到前台进行更新(update)

实现

服务端实现

定义一类订单类

package yybwb;

public class orderdetail {
 public Integer id;    //,
 public Integer orderID; 
 public Integer menuID; 
 public String num; 
 public Integer state; 
    public String Tno;    //    //
    public String remark; 
  
 
 public   orderdetail(int id,int orderID, int menuID,String num, int state,String Tno,String remark) 
    {
  this.id = id;
  this.orderID = orderID;
  this.menuID =  menuID;
  this.num = num;
  this.state = state;
  this.Tno= Tno;
  this.remark= remark;
   
 }
}

通过一方法获取订单信息

 1 public static ArrayList<orderdetail> getorderdetaillists(String Tabno){
 2   ArrayList< orderdetail> result = new ArrayList< orderdetail>();
 3   Connection con = null;   //声明Connection对象
 4   PreparedStatement ps = null;
 5   ResultSet rs = null;
 6   /*
 7    * tabletal的数据在新订单生成时修改
 8    */
 9   String sql = "select orderID,menuID,num,state,Tno,remark from orderdetailtal where state=1";
10   
11    try{
12    con = getConnection();  //获得连接
13    ps = con.prepareStatement(sql); //获得预编译语句
14    //ps.setInt(1, Integer.valueOf(r_id)); //设置参数
15    rs = ps.executeQuery();   //执行查询
16    while(rs.next()){
17      
18     String remark = rs.getString(6);
19     String Tno = rs.getString(5);
20    // int orderID = rs.getInt(1); 
21     int menuID = rs.getInt(2); 
22     double num = rs.getDouble(3); 
23      String.format("%.2f", num); //1.23
24     int state =rs.getInt(4);
25     
26     //new String(rs.getString(2).getBytes("ISO-8859-1"),CHAR_ENCODING);
27      // new String(rs.getString(3).getBytes("ISO-8859-1"),CHAR_ENCODING);
28     orderdetail c = new orderdetail(1,1,menuID, String.format("%.2f", num),state,Tno,remark);
29     result.add(c);
30     
31     //System.out.println(Tno+','+remark); 
32    }
33    System.out.println("get orderdetail lists");
34   }catch(Exception e){
35    e.printStackTrace();
36   }
37   finally{
38    try{
39     if(rs != null){
40      rs.close();
41      rs = null;
42     }
43    }catch(Exception e){
44     e.printStackTrace();
45    }
46    try{
47     if(ps != null){
48      ps.close();
49      ps = null;
50     }
51    }catch(Exception e){
52     e.printStackTrace();
53    }
54    try{
55     if(con != null){
56      con.close();
57      con = null;
58     }
59    }catch(Exception e){
60     e.printStackTrace();
61    }
62   }
63   return result;
64  }
65

将订单信息传递到客户端

 1 else if(msg.startsWith("<#GET_ORDERDETAIL#>")){//消息为获取台表2014-7-22
 2      msg = msg.substring(19);      //提取内容
 3      ArrayList<orderdetail> cmList = DBUtil.getorderdetaillists(msg); //获得台列表
 4      int size = cmList.size();   //个数
 5      dout.writeInt(size);    //返回个数
 6      String reply = din.readUTF();  //等待客户端反馈
 7      if(reply.equals("<#READY_TO_ORDERDETAIL#>")){ //如果客户端已经准备好
 8       for(orderdetail c:cmList){
 9        StringBuilder sb = new StringBuilder();
10        
11        sb.append(String.valueOf(c.id));
12        sb.append("|");
13        sb.append(String.valueOf(c.orderID));
14        sb.append("|");
15        sb.append(String.valueOf(c.menuID));
16        sb.append("|");
17           sb.append(c.num);
18        sb.append("|");
19        sb.append(String.valueOf(c.state));
20        sb.append("|");
21        sb.append(c.Tno);
22        sb.append("|");
23        sb.append(c.remark);
24        
25        dout.writeUTF(sb.toString());  //发送消息到客户端
26            }
27             }
28     }
29

客户端实现

定义一个订单类

 1 package com.realhope.rmeal.bean;
 2 
 3 /**
 4  * 
 5  * @author Wuchunyuan
 6  * 订单明细类
 7  */
 8 public class OrderDetail{ 
 9  private Integer _id;       
10     private Integer orderID;    
11     private Integer menuID;     
12     private String num;    // 数量
13     private Integer state;    // 状态 
14     private String remark;    // 备注
15     private String Tno;
16     
17  public OrderDetail() {
18   super();
19  }
20  public OrderDetail(Integer _id, Integer orderID, Integer menuID,
21    String num, Integer state, String Tno,String remark) {
22   super();
23   this._id = _id;
24   this.orderID = orderID;
25   this.menuID = menuID;
26   this.num = num;
27   this.state = state;
28   this.remark = remark;
29   this.Tno = Tno;
30  }
31  public Integer get_id() {
32   return _id;
33  }
34  public void set_id(Integer _id) {
35   this._id = _id;
36  }
37  public Integer getOrderID() {
38   return orderID;
39  }
40  public void setOrderID(Integer orderID) {
41   this.orderID = orderID;
42  }
43  public Integer getMenuID() {
44   return menuID;
45  }
46  public void setMenuID(Integer menuID) {
47   this.menuID = menuID;
48  }
49  public String getNum() {
50   return num;
51  }
52  public void setNum(String num) {
53   this.num = num;
54  }
55  public Integer getState() {
56   return state;
57  }
58  public void setState(Integer state) {
59   this.state = state;
60  }
61  public String getRemark() {
62   return remark;
63  }
64  public void setRemark(String remark) {
65   this.remark = remark;
66  }
67  
68  public String getTno() {
69   return Tno;
70  }
71  public void setTno(String Tno) {
72   this.Tno = Tno;
73  }
74  
75 }

发送获取订单的消息到服务器，得到服务器发来数据

 1  String msg = "<#GET_ORDERDETAIL#>"+TableN;
 2      mc.dout.writeUTF(msg); //发出获取新菜单表请求
 3      mc.dout.flush(); 
 4      int size = mc.din.readInt();   //获取个数 
 5       
 6      mc.dout.writeUTF("<#READY_TO_ORDERDETAIL#>");
 7      mc.dout.flush(); 
 8       
 9      for(int i=0;i<size;i++){
10        msg = mc.din.readUTF();  //读取每条信息
11        String [] sa = msg.split("\\|"); //切割字符串
12     
13     OrderDetail OrderDetaillists = new OrderDetail(Integer.valueOf(sa[0]),Integer.valueOf(sa[1]),
14     Integer.valueOf(sa[2]),String.valueOf(sa[3]),Integer.valueOf(sa[4]),String.valueOf(sa[5]),
15     String.valueOf(sa[6]));
16      ((MenuActivity)mContext).lstDate_OrderDetailLists.add(OrderDetaillists);
17     }        
18

执行SQl语句更新本地Sqlite数据库

 1 /  * 2014-10-14
 2   * @param lstDate_OrderDetailLists
 3   */
 4  
 5  public void updateOrderDetail(List<OrderDetail>  lstDate_OrderDetailLists){
 6   DBHelper dbM = new DBHelper(this.context);
 7   SQLiteDatabase db = dbM.getReadableDatabase();
 8   db.execSQL("DROP TABLE IF EXISTS OrderDetailTal");
 9   //db.execSQL("delete from   OrderDetailTal");
10   int Count=lstDate_OrderDetailLists.size();
11  //创建表
12   db.execSQL("CREATE TABLE " + OrderDetails.TABLE+ " ("
13     + OrderDetails._ID + " INTEGER PRIMARY KEY,"
14    + OrderDetails.ORDERID+ " INTEGER,"
15     + OrderDetails.MENUID+ " INTEGER,"
16     + OrderDetails.NUM + " REAL,"
17     + OrderDetails.STATE + " INTEGER,"
18     + OrderDetails.Tno + " TEXT,"
19     + OrderDetails.REMARK + " TEXT"
20      
21    + ");");
22  //逐一更新本地数据   
23    for(int i=0 ; i<Count ;){
24       db.execSQL("insert into "+OrderDetails.TABLE+" ("+OrderDetails.ORDERID+","+      OrderDetails.MENUID+","+
25    OrderDetails.NUM +","+
26    OrderDetails.STATE+","+OrderDetails.Tno +","+OrderDetails.REMARK +") " + 
27      "values ('"+String.valueOf(lstDate_OrderDetailLists.get(i).getOrderID())+"','"+
28    String.valueOf(lstDate_OrderDetailLists.get(i).getMenuID()) +"','"+
29    lstDate_OrderDetailLists.get(i).getNum() +"','"+
30    String.valueOf(lstDate_OrderDetailLists.get(i).getState()) +
31    "','"+String.valueOf(lstDate_OrderDetailLists.get(i).getTno()) +
32    "','"+String.valueOf(lstDate_OrderDetailLists.get(i).getRemark())+"')");
33   i++;
34   }
35   
36     db.close();
37  return;
38 }

App的前后台数据同步

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