Question

我有一个航空公司字符串数组，我需要解析为飞机对象数组的属性。我已经创建了对象数组，我使用我的setAirline方法有问题，程序编译但似乎没有存储值，截至目前我只有setAirline来测试它是否有效。

public class Project2 {

    // Input data - Airline, Flight Number, Make, Model, Departure City, Arrival City, Departure Time, Arrival Time
    final static String [][] DATA = {
            {"Air Berlin", "4504", "Boeing", "767-300", "Zurich (ZRH)", "New York, NY (JFK)", "2-26 1000", "2-26 1325"},
            {"Qatar Airways", "212", "Boeing", "767-300", "Milano (MXP)", "New York, NY (JFK)", "2-26 1000", "2-26 1330"},
            {"Jetblue Airways", "298", "Airbus", "A320", "Tampa, FL (TPA)", "New York, NY (JFK)", "2-26 0728", "2-26 0959"},                                       
            {"Air Canada", "6851", "Airbus", "A340-300", "Dakar (DKR)", "New York, NY (JFK)", "2-26 0255", "2-26 0650"},
            {"Alaska Airlines", "1219", "Boeing", "737-800", "Boston, MA (BOS)", "New York, NY (JFK)","2-26 0940", "2-26 1055"},
            {"Delta Airlines", "6182", "Canadadair", "CRJ", "Toronto (YYZ)", "New York, NY (JFK)", "2-26 0606", "2-26 0800"},
            {"American Airline", "199", "Boeing", "767-300", "Milano (MXP)", "New York, NY (JFK)", "2-26 1010", "2-26 1330"},
            {"United Airlines", "9855", "", "", "Cairo (CAI)", "New York, NY (JFK)", "2-26 1025", "2-26 0325"},
            {"Virgin America", "483", "Airbus", "A320", "San Francisco (SFO)", "New York, NY (JFK)", "2-25 2320", "2-26 0750"},
            {"Air France", "3650", "Boeing", "767-400", "Barcelona (BCN)", "New York, NY (JFK)", "2-26 1055", "2-26 0158"},
            {"Air China", "7266", "Boeing", "757-200", "Los Angeles, CA (LAX)", "New York, NY (JFK)","2-25 2159", "2-26 0616"}
    };

    public static class Air{

    private String airline, flightNumber, make, model, departure, arrival, departureTime, arrivalTime;
    public String getAirline(Air a){return airline;};
    public void setAirline(String n){airline = n;};
    public String getFlightNum(){return flightNumber;};
    public void setFlightNum(String n){flightNumber = n;};
    public String getMake(){return make;};
    public void setMake(String n){make = n;};
    public String getModel(){return model;};
    public void setModel(String n){model = n;};
    public String getDep(){return departure;};
    public void setDep(String n){departure = n;};
    public String getArrival(){return arrival;};
    public void setArrival(String n){arrival = n;};
    public String getDepTime(){return departureTime;};
    public void setDepTime(String n){departureTime = n;};
    public String getArrivalTime(){return arrivalTime;};
    public void setArrivalTime(String n){arrivalTime = n;};

    public Air(){
            make = "";
            model = "";
    }//default

    public Air(String ma,String mo){
            this.make=ma;
            this.model=mo;
    }//2 constructor

    public Air(String air, String flight,String ma,String mo){
            this.make=ma;
            this.model=mo;
            this.airline=air;
            this.flightNumber=flight;
    }//4 constructor

    }//Air class

    public static void main(String[] args) {

    // Create an Array of airplanes
            int size = DATA.length;
            Air[] airplanes = new Air[size];

    for(int i=0; i<size; i++){
            for(int j=0;j<8;j++){
                    airplanes[i].setAirline(DATA[i][j]);

    }//J-loop
    }//I-loop

    // Print out the original flight details
     // Sort it
     // Print out the updated flight details

    }//main
 }

Answer 1

请问我，但我认为该程序在运行时给你一个NullPointerException：

public static void main(String[] args) {         
    // Create an Array of airplanes
    int size = DATA.length;
    Air[] airplanes = new Air[size];

    for (int i=0; i<size; i++) {
      for (int j=0;j<8;j++) {
        airplanes[i].setAirline(DATA[i][j]);
      }//J-loop
    }//I-loop
 }//main

您没有初始化Air数组中的airplane个对象。代码airplanes[i].setAirline(DATA[i][j]);如何在不给你例外的情况下运行？！

Answer 2

你能解释一下，为什么你的Air.getAirline（）需要Air-param？也许这是一个错字，你最好用这个解决方案结束：

public class AirplanTest {

final static String[][] DATA = {
        { "Air Berlin", "4504", "Boeing", "767-300", "Zurich (ZRH)",
                "New York, NY (JFK)", "2-26 1000", "2-26 1325" },
        { "Qatar Airways", "212", "Boeing", "767-300", "Milano (MXP)",
                "New York, NY (JFK)", "2-26 1000", "2-26 1330" }
};

public static class Air {

    private String airline;

    public String getAirline() {
        return airline;
    };

    public void setAirline(String n) {
        airline = n;
    };

    public Air() {

    }// default


}// Air class

public static void main(String[] args) {        

    List<Air> airlines = new ArrayList<Air>();

    for (int i = 0; i < DATA.length; i++) {
        Air airplane = new Air();
        for (int j = 0; j < 8; j++) {
            airplane.setAirline(DATA[i][0]);

        }// J-loop
        airlines.add(airplane);
    }// I-loop


    // Print out the original flight details
    for(int i=0; i<airlines.size();i++){
        System.out.println(airlines.get(i).getAirline());
    }
    // Sort it
    // Print out the updated flight details


}// main

}

将字符串数组解析为对象属性

2 个答案: