hive自定义函数-空值过滤

• 简要
• 代码

过滤数据
null
‘null’
‘NULL’
‘’
’ ’
‘rn’
‘t’
‘n’
空值数据

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;

import java.util.regex.Pattern;


@Description(
        name = "udf_is_null",
        value = "_FUNC_(str) - Returns str is null?0:1",
        extended = "Example:n  > SELECt _FUNC_('Facebook') FROM dual LIMIT 1;n   return    1 "
)
public class UdfIsNull extends UDF {

    public int evaluate(final String s) {
        if (s == null  || s.toString().trim().toLowerCase().equals("null") || Pattern.matches("\s+",s.toString())||s.toString().trim().equals("")) {
            return 0;
        }
        return 1;
    }

    public static void main(String[] args) {
        System.out.println("值为"+new UdfIsNull().evaluate(new String("null"  )));
    }
}