Question

大家好我一直试图修复此问题但无法修复，问题是删除无法在hashmap中运行。

请参阅以下代码。

 package com.org.common;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

@SuppressWarnings("unused")
class Workindays {
    public static int findNoOfDays(int year, int month, int day) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, day);
        int days = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        return days;
    }
    public static Map<String, String> getHolydaysMap(int year, int month, int day) {
        //connect with database and check whether the date is holyday query is = SELECT * FROM holiday_calendar h WHERE date >='2008-10-01' AND date <='2008-10-30' AND type='Fixed';
        Map<String, String> holydaysMap = new LinkedHashMap<String,String>(); 

        holydaysMap.put("20","17-04-2012");
        holydaysMap.put("10","25-04-2012");
        return holydaysMap;
    }
    public static Map<String, String> getWorkingDaysMap(int year, int month, int day){
        int totalworkingdays=0,noofdays=0;
        String nameofday = "";
        ConcurrentHashMap<String,String> workingDaysMap = new ConcurrentHashMap<String,String>();
        Map<String,String> holyDayMap = new LinkedHashMap<String,String>();
        noofdays = findNoOfDays(year,month,day);
        holyDayMap = getHolydaysMap(year,month,day);

        for (int i = 1; i <= noofdays; i++) {
            Date date = (new GregorianCalendar(year,month - 1, i)).getTime(); // year,month,day
            SimpleDateFormat f = new SimpleDateFormat("EEEE");
            nameofday = f.format(date);
            String formatedDate = i+"-"+month+"-"+year;
            if(!(nameofday.equals("Saturday") || nameofday.equals("Sunday"))){
                workingDaysMap.put(String.valueOf(i),formatedDate);
                totalworkingdays++;
            }
        }
        workingDaysMap.put("totalworkingdays", String.valueOf(totalworkingdays));

        System.out.println("removeHolyday : "+removeHoliday(workingDaysMap,holyDayMap));
        return workingDaysMap;
    }
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static Map removeHoliday(ConcurrentHashMap daysMap, Map holydayMap) {
        Iterator<Map.Entry> holyDayiterator = holydayMap.entrySet().iterator();
        while (holyDayiterator.hasNext()) {
            Map.Entry holyDayEntry = holyDayiterator.next();

            Iterator<Map.Entry> daysiterator = daysMap.entrySet().iterator();
            while (daysiterator.hasNext()) {
                Map.Entry daysEntry = daysiterator.next();
                 if(daysEntry.getKey().equals(holyDayEntry.getKey()))
                      daysMap.remove(holyDayEntry.getKey());
            }
        }
        return daysMap;
    }
    @SuppressWarnings({ "rawtypes" })
    public static void main(String[] args) {
        String delimiter = null, dateValues[] = null, startDate = "01-04-2012";
        int year = 0,month=0,day=0,totalworkingdays = 0;
        Map workingDaysMap = new LinkedHashMap<String,String>();

        startDate = "01-04-2012";
        delimiter = "-";
        dateValues = startDate.split(delimiter);

        year = Integer.parseInt(dateValues[2]);
        month = Integer.parseInt(dateValues[1]);
        day = Integer.parseInt(dateValues[0]);

        workingDaysMap = getWorkingDaysMap(year, month, day);
        //System.out.println("workingdays map : "+workingDaysMap);

    }
}

这是我调用删除值的方法

removeHolyday

我刚刚给出了以下方法测试的样本值。

getHolydaysMap

请帮忙。

编辑：非常感谢所有那些已经花费了宝贵时间回答，upvote和downvote.i已经改变了代码的人，现在工作正常，

更新了工作代码。

此致安东尼

Answer 1

  if (Integer.parseInt(daysEntry.getKey().toString()) ==   Integer.parseInt(holyDayEntry.getKey().toString()))
                daysMap.remove( Integer.parseInt(holyDayEntry.getKey().toString()));
            break;

如果条件失败，它将会突破，而不是为Map的其余部分循环

Answer 2

您没有说明您遇到的具体错误，但有一些一般性意见要做。

你的break语句在“if”之外，所以代码将经过然后在第一个键之后退出while循环。换句话说，你实际上并没有迭代所有键。

其次，你不需要来迭代地图并测试匹配的密钥，调用remove会为你做这件事。

第三个（作为一个兴趣点）在迭代它时从地图中删除项将导致下一次循环时迭代器的异常。在这种特殊情况下没有突出显示，因为break语句可以帮助您避免错误，但值得注意未来。

Answer 3

在你的removeHoliday方法中

你需要parantheses;你需要以下内容：

if (Integer.parseInt(daysEntry.getKey().toString()) == Integer.parseInt(holyDayEntry.getKey().toString())) {
    daysMap.remove( Integer.parseInt(holyDayEntry.getKey().toString()));
    break;
}

代替

if (Integer.parseInt(daysEntry.getKey().toString()) ==     Integer.parseInt(holyDayEntry.getKey().toString()))
    daysMap.remove( Integer.parseInt(holyDayEntry.getKey().toString()));
break;

Answer 4

考虑重写removeHolydays：

而不是

  public static Map removeHolyday(Map daysMap, Map holydayMap) {
    Iterator<Map.Entry> holyDayiterator = holydayMap.entrySet().iterator();
    while (holyDayiterator.hasNext()) {
        Map.Entry holyDayEntry = holyDayiterator.next();
        Iterator<Map.Entry> daysiterator = daysMap.entrySet().iterator();

        while (daysiterator.hasNext()) {
            Map.Entry daysEntry = daysiterator.next();
            if (Integer.parseInt(daysEntry.getKey().toString()) == Integer.parseInt(holyDayEntry.getKey().toString()))
                daysMap.remove( Integer.parseInt(holyDayEntry.getKey().toString()));
            break;
        }
    }
    return daysMap;
}

应该是：

public static Map<Integer, String> remove(Map<Integer, String> daysMap, Map<Integer, String> holydayMap){
     for(Integer i : holydayMap.keySet())
         daysMap.remove(i);
     return daysMap;
}

这将消除break所指出的ejb_guy错误位置的错误

Answer 5

您可以使用ConcurrentHashMap执行此操作，

public static Map removeHolyday（ConcurrentHashMap daysMap，Map holydayMap）{

编辑：使用以下代码执行，

public static Map removeHoliday(ConcurrentHashMap daysMap, Map holydayMap) {
        Iterator<Map.Entry> holyDayiterator = holydayMap.entrySet().iterator();
        while (holyDayiterator.hasNext()) {
            Map.Entry holyDayEntry = holyDayiterator.next();
            if(daysMap.containsKey(holyDayEntry.getKey())){
                daysMap.remove(holyDayEntry.getKey());
            }
        }
        return daysMap;
    }

删除是不是在java中的hashmap中工作？

5 个答案: