我对pig-udf是个新手，尝试了我的第一个。我想评估两列的差异。假设a和b是我的列，我想评估（a-b）
下面是我的javaudf代码

public class GlaasDiff extends EvalFunc<Double> {
@Override
public Double exec(Tuple input) throws IOException {
    if(input==null || input.size()!=2){
        System.err.println("input passed is either null or not equals two!!");
        return null;
    }
    try{
        Double a =(Double) input.get(0);
        Double b =(Double) input.get(1);
        a = Math.round(a * 100.0) / 100.0;
        b = Math.round(b * 100.0) / 100.0;
        Double diff= a-b;
        Double roundOff = Math.round(diff * 100.0) / 100.0;
        return roundOff;
    }catch (Exception e){
        System.err.println("Failed to process input");
        return null;
    }
  }
}

下面是使用udf的pig脚本

REGISTER hdfs:///user/gadmin/glaas/lib/udf-1.0.jar
A = LOAD 'file' using PigStorage(',') AS (Product,TotalInvoices:float,Approved:float) ;
Final = FOREACH A GENERATE Product,packagname.GlaasDiff(TotalInvoices,Approved);
dump Final;

输出是唯一的产品和空白这样

p1, 
 p2,
 p3,
 p4,

然后我尝试了一个使用trim函数的简单示例，比如下面的.java代码

public class GlaasTrim extends EvalFunc<String> {
@Override
public String exec(Tuple input) throws IOException {
    if (input == null || input.size() == 0)
        return null;
    try{
        String str = (String)input.get(0);
        getLogger().info(str.trim());
        return str.trim();
    }catch(Exception e){
        System.out.println("Error occured!!!");
        return null;
    }
 }
}

Pig手稿

A = LOAD 'file' using PigStorage(',') AS (Product,TotalInvoices:float,Approved:float) ;
Final = FOREACH A GENERATE packagname.GlaasTrim(Product);
dump Final;

现在我没有得到任何输出。我不知道发生了什么。日志记录也不起作用。我使用的是pig版本0.12.0-cdh5.3.3和java1.7
请帮我解决这个问题。