Question

存储在数组中的日期如何将所有jan月份日期分别分组在不同的数组中

String s[]={"2016-05-8","2016-01-18","2016-03-23","2016-01-15","2016-02-12","2016-03-7"};


    SimpleDateFormat newformat = new SimpleDateFormat("dd-MM-yyyy");

            String jan[]=new String[10];
            String march[]=new String[10];
             for(int i=0;i<s.length;i++)
             {

                 int month=Integer.parseInt(date.split("-")[1]);

                switch(month)
                 {
                 case 01:
                     System.out.println("JAN month");
                    String[] jan=new String[10];
                    for(int k=0;k<3;k++)
                    {
                    jan[k]=date;

                    }

                    System.out.println("dates in jan month "+jan[0]);
                    System.out.println("dates in jan month "+jan[1]);

                     break;
                 case 02:
                     System.out.println("-------------------------------------------------");
                     System.out.println("FEB month");
                        String[] feb=new String[10];
                        for(int k=0;k<3;k++)
                        {
                        feb[k]=date;
                        }
                        System.out.println("dates in jan month "+feb[0]);


                    break;
                 case 03:
                     System.out.println("march month");
                    break;
                 case 04:
                     System.out.println("apr month");
                    break;
                 case 05:
                     System.out.println("-------------------------------------------------");
                     System.out.println("MAY month");
                        String[] may=new String[10];
                        for(int k=0;k<3;k++)
                        {
                        may[k]=date;
                        }
                        System.out.println("dates in MAY month "+may[0]);
                    break;




                 }

             }

Answer 1

String[] months = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };
    String[] s = { "2016-05-8", "2016-01-18", "2016-03-23", "2016-01-15", "2016-02-12", "2016-03-7" };
    Map<String, List<String>> datesMap = new HashMap<String, List<String>>(s.length);
    for (String date : s) {
        String month = date.substring(date.indexOf("-") + 1, date.lastIndexOf("-"));
        List<String> strings = datesMap.get(month);
        if (strings == null) {
            strings = new ArrayList<String>();
            datesMap.put(month, strings);
        }
        strings.add(date);
    }
    Set<String> month = datesMap.keySet();
    for (String date : month) {
        List<String> list = datesMap.get(date);
        if (list != null && !list.isEmpty()) {
            System.out.println("dates in " + months[Integer.parseInt(date) - 1] + "  month:" + list.toString());
        }
    }

欢迎你。我的名字是雷锋

Java数组拆分方法

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