java - 如何在 java 中循环时从 MySQL 结果集中添加值？

Question

我想通过使用 while 循环迭代结果集来添加从 MySQL 数据库获得的整数列“优先级”的值。我的一段代码如下:

    int TotalWestPriority = 0;
    int WestPty = 0;

    float lat = 0;
    float lon = 0;

    float Wb_SWLat = 0; // Currently holds some value from other process
    float Wb_NELat = 0; // Currently holds some value from other process
    float Wb_SWLon = 0; // Currently holds some value from other process
    float Wb_NELon = 0; // Currently holds some value from other process


//SQL Query:
    String qryVcl = "select priority, latitude, longitude from tbl_vcl";

    ResultSet Vp=stmt.executeQuery(qryVcl);

    while(Vp.next()){
        lat = Vp.getFloat("latitude");
        lon = Vp.getFloat("longitude");
        System.out.println("Total Lat received:"+lat);

        if(lat >=Wb_SWLat && lat <=Wb_NELat && lon>=Wb_SWLon && lon<=Wb_NELon){
            WestPty = Vp.getInt("priority");
            System.out.println("West Priority:"+WestPty);
        }
        }

---

在这里，我可以打印结果:-

西部优先级:3

西部优先级:2

我想将这些值相加并存储在一个整数中。

如何将迭代中的所有“westpty”添加到“TotalWestPriority”？

Answer 1

只需将它们累加到另一个变量:

long total = 0L;
while (vp.next()) {
    lat = vp.getFloat("latitude");
    lon = vp.getFloat("longitude");

    if (lat >= Wb_SWLat && lat <= Wb_NELat && 
        lon >= Wb_SWLon && lon <= Wb_NELon) {

        westPty = Vp.getInt("priority");
        System.out.println("West Priority:"+WestPty);

        total += westPty;
    }
}

System.out.println("Total west priority: " + total);