java - 如何从数组列表中检索值并根据所选国家/地区显示？

Question

我声明了一个数组列表。如何根据国家/地区检索这些值并一一显示结果？

例如，对于 SearchofCountry，如果我选择选项 1:美国。它会从我的数组列表中一一检索出 USA 的所有结果。我该怎么做？

public class Assignment {

        //Declare variables
        public static String[] country;
        public static String[] description;
        public static String[] travelmonth;
        public static double[] price; 
        public static String[] travelpackage;
        public static String[] newls;

    public static void main(String[] args) {

            country = new String[8];
            country[0] = "Australia";
            country[1] = "Australia";
            country[2] = "Australia";
            country[3] = "China";
            country[4] = "China";
            country[5] = "USA";
            country[6] = "USA";
            country[7] = "USA";

            travelmonth = new String[8];
            travelmonth[0] = "June";
            travelmonth[1] = "June";
            travelmonth[2] = "July";
            travelmonth[3] = "August";
            travelmonth[4] = "September";
            travelmonth[5] = "October";
            travelmonth[6] = "October";
            travelmonth[7] = "December";

            description = new String[8];
            description[0] = "6D5N Gold Coast Adventure";
            description[1] = "5D4N Melbourne Tour";
            description[2] = "6D5N Sydney City and Wine Tour";
            description[3] = "4D3N Beijing City and Great Wall Adventure";
            description[4] = "5D4N Hangzhou Scenic Tour";
            description[5] = "8D7N California Adventure";
            description[6] = "6D5N New York Shopping Trip";
            description[7] = "8D7N Los Angeles, Las Vegas Winter Wonderland";

            price = new double[8];
            price[0] = 1600;
            price[1] = 1405.5;
            price[2] = 1700;
            price[3] = 880;
            price[4] = 990;
            price[5] = 2500;
            price[6] = 2106.6;
            price[7] = 2650.1;

            travelpackage = new String[8];
            travelpackage[0] = "1 of 8";
            travelpackage[1] = "2 of 8";
            travelpackage[2] = "3 of 8";
            travelpackage[3] = "4 of 8";
            travelpackage[4] = "5 of 8";
            travelpackage[5] = "6 of 8";
            travelpackage[6] = "7 of 8";
            travelpackage[7] = "8 of 8";

            int choice = 0;

            do {

                String msg ="Main Menu\n";
                msg += "===========\n";
                msg+= "1. Display all Travel Packages\n";
                msg+= "2. Random tour selection\n";
                msg+= "3. Search by country\n";
                msg+= "0. Quit";

                //choice is an integer, therefore you need to convert
                choice = Integer.parseInt(JOptionPane.showInputDialog(msg));

                if(choice == 1) {

                    displayAllPackages();

                }

                if(choice == 2) {

                    JOptionPane.showMessageDialog(null, "Are you ready for your next holiday?");

                    generateRandomPackage();

                }

                if(choice == 3) {

                    searchByCountry();

                }

            }

            while(choice!=0);

            JOptionPane.showMessageDialog(null, "Thank You for using the system");

        }

    public static void searchByCountry() {

            List<String> listString = new ArrayList<String>();

                listString.add("Australia");
                listString.add("Australia");
                listString.add("Australia");
                listString.add("China");
                listString.add("China");
                listString.add("USA");
                listString.add("USA");
                listString.add("USA");

            Set<String> setString = new HashSet<String>(listString);

            listString.clear();

            listString.addAll(setString);

            String msgs = "";

            int countryno = 0;

                        msgs = ""; //reset
                        msgs+= "Enter country number\n";
                        msgs+= "1. " +listString.get(0) + "\n";
                        msgs+= "2. " +listString.get(1) + "\n";
                        msgs+= "3. " +listString.get(2) + "\n";

            countryno = Integer.parseInt(JOptionPane.showInputDialog(msgs));            

                if(countryno == 1) {

                    showAllUSA1();

                }

    }

    public static void showAllUSA1() {

            String msg = "";
            int index = 0;

            String inChoice ="";

                msg = ""; //reset
                msg+= "Search result : 1 \n";
                msg+= "==============\n";
                msg+= "Country : " +country + "\n";
                msg+= "Month : " +travelmonth [index] + "\n";
                msg+= "Description : " +description [index] + "\n";
                msg+= "Price : " +price [index] + "\n";
                msg+= "===============\n";
                msg+= "Enter M to return to main menu\n";

                for(int i=0; i< country.length; i++)

                System.out.println(i + ":" +country[i]);
                //inChoice = JOptionPane.showInputDialog(msg);  


            }

}

Answer 1

您有一堆按索引关联的数组。与其将它们放入数组中，为什么不为每个创建一个对象呢？

public class TravelPlan {
    String country;
    String description;
    String travelmonth;
    double price; 
    String travelpackage;
    String newls;

    public TravelPlan() {
    }

    public TravelPlan(String country,
                      String description,
                      String travelmonth,
                      double price,
                      String travelpackage) {
          this.country = country;
          this.description = description;
          this.travelmonth = travelmonth;
          this.price = price;
          this.travelpackage = travelpackage;
    }
  // add setters/getters here for example
  String getCountry() {
      return(country);
  }
  void setCountry(String country) {
      this.country = country;
  }
  double getPrice() {
     return(price);
  }
  void setPrice(double price) {
     this.price = price;
  }
   // continue with rest of class variables here
 }

然后你可以通过以下方式实例化它:

TravelPlan one = new TravelPlan ("Australia", 
                                 "June",
                                 "6D5N Gold Coast Adventure",
                                 1600,
                                 "1 of 8");

现在您可以将它们放入数组或列表中。

  java.util.List<TravelPlan> travelPlans = new java.util.ArrayList<>();
  travelPlans.add(one);
  // add rest here

通过这样做，所有数组现在都变成对象了，这使得搜索变得更容易。

for (TravelPlan s : travelPlans) {
     if ("USA".equals(s.getCountry()) {
          //we have a match for USA, do whatever ...
     }
 }

假设 TravelPlans 是所有可能的 TravelPlan 的列表，您可以使用以下方法按国家/地区搜索。

List<TravelPlan> getListByCountry(String searchCountry) {
    List<TravelPlan> retValue = new ArrayList<>();
    for (TravelPlan s: travelPlans) {
        String tempCountry = s.getCountry();
        if (tempCountry != null) {
           if (tempCountry.equals(searchCountry)) {
               retValue.add(s);
           }
        }
     }
     return(retValue)
}

通过以下方式调用:

List matches = getListByCountry("USA");