UDF函数：判断日期是否为月末日期?

布满荆棘的人生 2022-05-26 11:08 300阅读 0赞

需求：判断一个日期是否为当月月末日期？

import org.apache.commons.lang.StringUtils;
    import org.apache.hadoop.hive.ql.exec.UDF;
    import org.apache.hadoop.io.BooleanWritable;
    
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    import java.util.Date;
    
    /**
     * 判断日期是否是月的最后一天 返回ture false
     */
    public class UDFIsMonthLastDay extends UDF
    {
        SimpleDateFormat simDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        Date date;
        Calendar calendar = Calendar.getInstance();
        int dayMax = 0;
    
        BooleanWritable result = new BooleanWritable();
    
        public BooleanWritable evaluate(String dateStr) throws ParseException
        {
            if (StringUtils.isBlank(dateStr))
                return null;
    
            date = simDateFormat.parse(dateStr);
            calendar.setTime(date);
            dayMax = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
    
            result.set(false);
            if (dayMax == calendar.get(Calendar.DAY_OF_MONTH))
                result.set(true);
            else
                result.set(false);
    
            return result;
        }
    
        public static void main(String[] args) throws Exception
        {
            UDFIsMonthLastDay o = new UDFIsMonthLastDay();
            System.out.println(o.evaluate("2012-02-29"));    
            System.out.println(o.evaluate("2000-02-28"));//false
            System.out.println(o.evaluate("2017-02-28"));
            System.out.println(o.evaluate("2017-02-30"));   //虚假日期，不会报错，但是为false
        }
    }
    
    输出结果显示：
    true
    false
    true
    false