Question

这是我在Java中想要的数据的表示。

e.g。国家 - ＆gt;联赛 - ＆gt;季节 - ＆gt;初始评级为0的团队

主机
- PRL
  - 2013/14
    - 阿森纳0
    - 曼彻斯。 0
  - 2014/15
    - 阿森纳0
    - 曼彻斯。 0
- CHA
  - 2013/14
GER
- BUN
  - 2013/14
    - BayernM 0

但问题在于，值似乎通过Java的值引用传递来覆盖。

因此，我总是在地图中获得一个结果，而不是一种列表。

在这里，您将看到我对象Season的实现。

public class Season {

    private HashMap<String, Map<String, Map<String, Map<String, Double>>>> mapSeasonsLeaguesAndTeams;

    public Season() {
        this.mapSeasonsLeaguesAndTeams = new HashMap<String, Map<String, Map<String, Map<String, Double>>>>();
    }

    public void collectSeasons(String country, String league, String season,
            String team) {
        Map<String, Map<String, Double>> seasonTeam = new HashMap<String, Map<String, Double>>();
        Map<String, Double> teamRating = new HashMap<String, Double>();
        Map<String, Map<String, Map<String, Double>>> leagueSeason = new HashMap<String, Map<String, Map<String, Double>>>();


// check if the the country already exist otherwise create new
        if (mapSeasonsLeaguesAndTeams.containsKey(country)) {


// check if the league already exists if that country exists
            if (mapSeasonsLeaguesAndTeams.get(country).containsValue(league)) {



// check if the season exists if we know we have a valide country and league
                if (mapSeasonsLeaguesAndTeams.get(country).get(league)
                        .containsKey(season)) {


// check if that team exists in the season of that league in that country
// if it exists, do nothing otherwise put it in
                    if (mapSeasonsLeaguesAndTeams.get(country).get(league)
                            .get(season).containsKey(team)) {

                    } else {
                        teamRating.put(team, 0.0);
                        mapSeasonsLeaguesAndTeams.get(country).get(league)
                                .put(season, teamRating);
                    }
                }
            } else {
                teamRating.put(team, 0.0);
                seasonTeam.put(season, teamRating);
                mapSeasonsLeaguesAndTeams.get(country).put(league, seasonTeam);
            }
        } else {
            teamRating.put(team, 0.0);
            seasonTeam.put(season, teamRating);
            leagueSeason.put(league, seasonTeam);
            mapSeasonsLeaguesAndTeams.put(country, leagueSeason);
        }
    }
}

Answer 1

我已经找到了解决方案。问题是它覆盖了现有的地图。换句话说，我必须检查它是否已经存在

解决方案

public void collectSeasons(String country, String league, String season,
            String team) {

        try {           
            if(!mapSeasonsLeaguesAndTeams.get(country).get(league).get(season).containsKey(team)){
                mapSeasonsLeaguesAndTeams.get(country).get(league).get(season).put(team, 0.0);
            }
        } catch (Exception e) {

        if (mapSeasonsLeaguesAndTeams.containsKey(country)) {
            if (mapSeasonsLeaguesAndTeams.get(country).containsKey(league)) {
                Map<String,Double> teamRating = new HashMap<String,Double>();
                Map<String, Map<String, Double>> seasonTeam = new HashMap<String, Map<String, Double>>();

                teamRating.put(team, 0.0);
                seasonTeam.put(season, teamRating);
                mapSeasonsLeaguesAndTeams.get(country).get(league).put(season, teamRating);

            } else {
                Map<String,Double> teamRating = new HashMap<String,Double>();
                Map<String, Map<String, Double>> seasonTeam = new HashMap<String, Map<String, Double>>();

                teamRating.put(team, 0.0);
                seasonTeam.put(season, teamRating);
                mapSeasonsLeaguesAndTeams.get(country).put(league, seasonTeam);
            }
        } else {
            Map<String,Double> teamRating = new HashMap<String,Double>();
            Map<String, Map<String, Double>> seasonTeam = new HashMap<String, Map<String, Double>>();
            Map<String, Map<String, Map<String, Double>>> leagueSeason = new HashMap<String, Map<String, Map<String, Double>>>();

            teamRating.put(team, 0.0);
            seasonTeam.put(season, teamRating);
            leagueSeason.put(league, seasonTeam);
            mapSeasonsLeaguesAndTeams.put(country, leagueSeason);
            }
        }
    }

因此，我使用了try catch。换句话说，将“新团队”添加到嵌套的哈希映射中“只是尝试”。

如果失败了。检查哪个hashmap“还没有”。如果您已找到它，请创建所需的哈希图并添加它们

为什么

with：

mapSeasonsLeaguesAndTeams.get(country).get(league).get(season).get(team)

我得到了所需的结果+它很灵活。

Java按值引用传递问题，在地图中映射到地图中

1 个答案:

解决方案

为什么