輸出Resultset的總數(shù)位601.
sql語句查詢結(jié)果如下，
注意：我將下面兩行都注釋了，不過調(diào)試時(shí)while（rs.next（））{}還是就執(zhí)行一次。
//rs.last();//到ResultSet最后一行
//System.out.println(rs.getRow());//最后一行的RowId為601
1 //查詢所有站點(diǎn)一天內(nèi)自行車借出數(shù)目和歸還數(shù)目、剩余自行車數(shù)目、站點(diǎn)名稱、站點(diǎn)編號
2 public List<stationInfo> QueryStationInfo(){
3 List<stationInfo> stationInfolist = new ArrayList<stationInfo>();
4
5 String sql="select distinct stationId,stationName,stationlon,stationlat from station Order by stationId ASC";
6 dbh = new DBHelper(sql);
7 try {
8 rs = dbh.ps.executeQuery(sql);// 執(zhí)行語句，得到結(jié)果集
9 //rs.last();//到ResultSet最后一行 調(diào)試時(shí)注釋了
10 //System.out.println(rs.getRow());//最后一行的RowId為601
11
12 while(rs.next()){
13 System.out.println(rs.getRow());
14 //if( (rs.getString("stationlon")!=null)
15 // &&(rs.getString("stationlat")!=null) ){
16
17 int iStationId = Integer.parseInt(rs.getString("stationId"));
18 String StationName = rs.getString("stationName");
19 float Stationlon = Float.parseFloat(rs.getString("stationlon"));
20 float Stationlat = Float.parseFloat(rs.getString("stationlat"));
21 float lendNum = QueryNumOfLend(iStationId); //獲得一天內(nèi)該站點(diǎn)借出自行車數(shù)目
22 float returnNum = QueryNumOfReturn(iStationId); //獲得一天內(nèi)該站點(diǎn)借出自行車數(shù)目
23 float leftNum = (float)(INITIAL_VALUE - lendNum + returnNum); //剩余自行車數(shù)目
24 /*System.out.println("iStationId:" + iStationId);
25 System.out.println("StationName:" + StationName);
26 System.out.println("Stationlon:" + Stationlon);
27 System.out.println("Stationlat:" + Stationlat);
28 System.out.println("lendNum:" + lendNum);
29 System.out.println("returnNum:" + returnNum);
30 System.out.println("leftNum:" + leftNum);*/
31
32 stationInfo stationinfo = new stationInfo();
34 stationinfo.setStationId(iStationId);
35 stationinfo.setStationName(StationName);
36 stationinfo.setStationlat(Stationlat);
37 stationinfo.setStationlon(Stationlon);
38 stationinfo.setInvitialNum(INITIAL_VALUE);
39 stationinfo.setStationReturnNum(returnNum);
40 stationinfo.setStationLendNum(lendNum);
41 stationinfo.setLeftNum(leftNum);
42 stationInfolist.add(stationinfo);
43 //}
44 }
45 for(stationInfo book : stationInfolist){
46 System.out.println(book.getStationId());
47 System.out.println(book.getStationlat());
48 System.out.println(book.getStationLendNum());
49
50 }
51 //rs.close();
52 //dbh.close();// 關(guān)閉連接
53 } catch (Exception e){
54 e.printStackTrace();
55 }
56 return stationInfolist;
57 }
58
59 //++根據(jù)用戶所選擇的站點(diǎn)編號 查詢一天內(nèi) 該站點(diǎn) 自行車借出數(shù)目
60 public float QueryNumOfLend(int iStationId){
61 float iRecordNum = 0;
62 String sql="select * from record where stationGoId ="+iStationId;
63 dbh =new DBHelper(sql);
64 try{
65 rs = dbh.ps.executeQuery(sql);// 執(zhí)行語句，得到結(jié)果集
66 while(rs.next()){
67 iRecordNum += 1;
68 }
69 System.out.println(iRecordNum);
70 //rs.close();
71 //dbh.close();// 關(guān)閉連接
72 } catch (Exception e) {
73 e.printStackTrace();
74 }
75 return iRecordNum;
76 }
77
78 //++根據(jù)用戶所選擇的站點(diǎn)編號 查詢一天內(nèi) 該站點(diǎn) 自行車歸還數(shù)目
79 public float QueryNumOfReturn(int iStationId){
80 float iRecordNum = 0;
81 String sql="select * from record where stationBackId ="+iStationId;
82 dbh = new DBHelper(sql);
83 try{
84 rs = dbh.ps.executeQuery(sql);// 執(zhí)行語句，得到結(jié)果集
85 while(rs.next()){
86 iRecordNum += 1;
87 }
88 System.out.println(iRecordNum);
89 //rs.close();
90 //dbh.close();// 關(guān)閉連接
91 } catch (Exception e) {
92 e.printStackTrace();
93 }
94 return iRecordNum;
95 }
?
java while(rs.next()){}只執(zhí)行一次？sql語句查過數(shù)據(jù)為601條，輸出Resultset為601條。詳見內(nèi)容
炎炎設(shè)計(jì)
2018-12-07 01:38:05
