java如何在迭代字符串数组列表时创建复杂的嵌套对象

Question

我有这样一个输入

private String[] one = {"North America","USA","IL","ch","chicago"};
private String[] two = {"North  America","USA","WI","ma","madision"};
private String[] three = {"Asia","India","AP","nlr","nlr"};
private String[] four = {"asia","india","TN","ch","chennai"};

并将像这样添加到列表中

private List<String[]> entities = new ArrayList<>();

    private void initializeStringArray(){
    entities.add(one);
    entities.add(two);
    entities.add(three);
    entities.add(four);
 }

现在，我想将这些实体转换为嵌套对象，如 大陆->；国家->；国家->；地区->；城市希望了解创建嵌套对象的最佳解决方案。创建嵌套对象时会非常混乱。谁能给我最好的解决办法

public class Continents{
   private String name;
   private Collection<Country> countryCollection;
}

public class Country{
 private String name;
 private Collection<State> stateCollection;
}

public class State{
private String name;
private Collection<District> districtCollection;
}

public class District{
 private String name;
private Collection<City> cityCollection;
}

public class City{
private String name;
} 

Answer 1

警告：我不知道如何确定哪种解决方案可能是“最好的解决方案”。然而，这里是一个可能的解决方案，也许不是最好的

我假设您只希望有一个“北美”的实例，用于“芝加哥”和“Madison”。因此，也许可以创建一个有大陆词典的“世界”类：

未经测试的代码：

public final class World {
    public static final World shared = new World(); // singleton
    private Map<String, Continent> continents = new HashMap<>();

    private World() {}  // enforce singleton

    public final Continent getContinent(String name) {
        String lowerCaseName = name.toLowerCase();
        Continent continent = this.continents.get(lowerCaseName);
        if (null == continent) {
            continent = new Continent(name);
            this.continents.put(lowerCaseName, continent);
        }
        return continent;
    }

}

世界是独特大陆实例的集合，也是新大陆的工厂

然后，欧洲大陆就会有一张国家地图，充当国家的工厂，在你们的层级结构中重复这种模式

然后，您的代码与（未经测试的代码）类似：

Continent continent = World.getContinent(one[0]);
Country country = continent.getCountry(one[1]);
State state = country.getState(one[2]);
.........

这里的关键点是，每一层都充当一个容器和一个工厂，用于下一层的唯一实例