Question

我知道从我的文件读取的数据已经过正确解析和读取，但当我尝试将其添加到CREATE OR REPLACE FUNCTION my_cursor(db_name TEXT, tbl_schema TEXT, tbl_name TEXT, col_type TEXT) RETURNS void AS $func$ DECLARE cid record; BEGIN FOR cid IN SELECT * FROM information_schema.columns AS ic WHERE ic.table_catalog=db_name AND ic.table_schema=tbl_schema AND ic.table_name=tbl_name AND ic.data_type=col_type LOOP EXECUTE format('ALTER TABLE %I.%I ALTER COLUMN %I TYPE text', cid.table_schema, cid.table_name, cid.column_name); END LOOP; RETURN; END; $func$ LANGUAGE plpgsql; SELECT my_cursor('database10232016', 'public', 'continent', 'character varying'); arraylist个CTARoute对象时，我会尝试ArrayIndexOutOfBoundsException从显然不存在的索引中调用get方法。

此外，reader = new ReadFile();中的行CTARoute似乎存在问题。

CTARoute class：

public class CTARoute{

        static ReadFile reader;

        private String StationName;
        private double Latitude;
        private double Longitude;
        private String Location;
        private boolean WheelChair;
        private int GreenLine;
        private int RedLine;

        public CTARoute(){

            StationName = "";
            Latitude = 0;
            Longitude = 0;
            Location = "elevated";
            WheelChair = true;
            GreenLine = 0;
            RedLine = 0;

        }

        public CTARoute(String StationName, double Latitude, double Longitude, String Location, boolean wheelChair, int GreenLine,int RedLine){


            this.StationName = StationName;
            this.Latitude = Latitude;
            this.Longitude = Longitude;
            this.Location = Location;
            this.WheelChair = WheelChair;
            this.GreenLine = GreenLine;
            this.RedLine = RedLine;
        }
        public String getStationName(){
            return StationName;
        }
        public Double getLatitude(){
            return Latitude;
        }
        public Double getLongitude(){
            return Longitude;
        }
        public String getLocation(){
            return Location;
        }
        public Boolean getWheelChair(){
            return WheelChair;
        }
        public int getGreenLine(){
            return GreenLine;
        }
        public int getRedLine(){
            return RedLine;
        }

        public void setStationName(String station){
            StationName = station;
        }
        public void setLatitude(double lat){
            Latitude = lat;
        }
        public void setLongitude(double lon){
            Longitude = lon;
        }
        public void setLocation(String loc){
            Location = loc;
        }
        public void setWheelChair(Boolean whe){
            WheelChair = whe;
        }

    public static void main(String args[]){ 

        Scanner scan = new Scanner(System.in);

         reader = new ReadFile();
}

ReadFile类：

public class ReadFile {

    ArrayList<CTARoute> route;


    public ReadFile(){


     String csvFile = "CTAStops(1).csv";
     File file = new File(csvFile);

     try{

         Scanner inputStream = new Scanner(file);
         inputStream.nextLine();

         while(inputStream.hasNextLine()){

             route = new ArrayList<CTARoute>();

             String data = inputStream.nextLine();
             String var[] = data.split(",");


            route.add(new CTARoute(var[0],Double.parseDouble(var[1]),Double.parseDouble(var[2]),var[3],Boolean.parseBoolean(var[4]),Integer.parseInt(var[5]),Integer.parseInt(var[6])));


         }

         inputStream.close();

     System.out.println(route.get(2).getStationName()); //testing to see if CTARoute objects are actually added to route.....

     }catch (FileNotFoundException e){

         e.printStackTrace();
     }  

 }

}

Answer 1

问题在于下面的代码导致ArrayIndexOutOfBoundsException当CTAStops(1).csv文件中的一行不包含带分隔符的7个元素时，

 route.add(new CTARoute(var[0],Double.parseDouble(var[1]),Double.parseDouble(var[2]),var[3],Boolean.parseBoolean(var[4]),Integer.parseInt(var[5]),Integer.parseInt(var[6])));

另外，请注意，构造函数应该只用于初始化类的实例变量（look here），并且最好的做法是在构造函数中编写复杂的逻辑（就像你在{{1中所做的那样）这是错的）。您的代码很难阅读和维护。

如何从文件读取的数据中将对象添加到我的arraylist？

1 个答案: