UDF函数：根据日期生日等查询星座

你的名字 2022-05-24 12:12 272阅读 0赞

自定义UDF函数实现：根据用户的生日，判断用户是什么星座.

import org.apache.hadoop.hive.ql.exec.Description;
    import org.apache.hadoop.hive.ql.exec.UDF;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.Text;
    import org.joda.time.DateTime;
    import org.joda.time.format.DateTimeFormat;
    import org.joda.time.format.DateTimeFormatter;
    
    import java.util.Date;
    
    /**
     * 此函数实现用户输入字符串格式为yyyy-MM-dd形式的日期，返回该用户的星座类型
     */
    @Description(name = "zodiac_cn"
            , value = "_FUNC_(date) - from the input date string or separate month and day arguments, returns the sing of the Zodiac."
            , extended = "Example:\n > select _FUNC_(date_string) from src;\n > select _FUNC_(month, day) from src;")
    public class UDFZodiacSignCn extends UDF {
        //日期的输入格式固定为:yyyy-MM-dd
    	public final static DateTimeFormatter DEFAULT_DATE_FORMATTER = DateTimeFormat.forPattern("yyyy-MM-dd");
       
        private Text result = new Text();
    
        public UDFZodiacSignCn() {
        }
    
        public Text evaluate(Text birthday) {
            DateTime dateTime = null;
            try {
                dateTime = DateTime.parse(birthday.toString(), DEFAULT_DATE_FORMATTER);
            } catch (Exception e) {
                return null;
            }
    
            return evaluate(dateTime.toDate());
        }
    
        public Text evaluate(Date birthday) {
            DateTime dateTime = new DateTime(birthday);
            return evaluate(new IntWritable(dateTime.getMonthOfYear()), new IntWritable(dateTime.getDayOfMonth()));
        }
    
        public Text evaluate(IntWritable month, IntWritable day) {
            result.set(getZodiac(month.get(), day.get()));
            return result;
        }
    
        private String getZodiac(int month, int day) {
            String[] zodiacArray = {"魔羯座", "水瓶座", "双鱼座", "白羊座", "金牛座", "双子座", "巨蟹座", "狮子座", 
                                     "处女座", "天秤座", "天蝎座", "射手座"};
            int[] splitDay = {19, 18, 20, 20, 20, 21, 22, 22, 22, 22, 21, 21}; // 两个星座分割日
            int index = month;
            // 所查询日期在分割日之前，索引-1，否则不变
            if (day <= splitDay[month - 1]) {
                index = index - 1;
            } else if (month == 12) {
                index = 0;
            }
            // 返回索引指向的星座string
            return zodiacArray[index];
        }
        
        public static void main(String[] args) {
    		UDFZodiacSignCn udfZodiacSignCn = new UDFZodiacSignCn();
    		System.out.println("1990-11-02:     "+udfZodiacSignCn.evaluate(new Text("1990-11-02")));
    		//错误格式的日期，返回值为null
    		System.out.println(udfZodiacSignCn.evaluate(new Text("19901102")));
    		System.out.println("2000-11-02:     "+udfZodiacSignCn.evaluate(new Text("2000-11-02")));
    		System.out.println("2000-01-02:     "+udfZodiacSignCn.evaluate(new Text("2000-01-02")));
    		
    	}
    }
    
    测试结果显示：
    1990-11-02:     天蝎座
    null
    2000-11-02:     天蝎座
    2000-01-02:     魔羯座