CODEWITHSUNDEEP
javaapachehadoopmapreduce
Darnold14
Darnold14

Reputation: 29

Map Reduce Array Out of Bounds Exception

I am very confused why this is happening. I have been working on this for some time and I just don't understand.

My Map code works as I am able to verify the output in the directory it is in.

This is the method:

public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {

        String stateKeyword = value.toString();
        String[] pieces = new String[] {stateKeyword};

        for (String element : pieces) {
            String name = element.split(":")[0].trim();
            String id = element.split(":")[1].trim();
            Integer rank = Integer.parseInt(element.split(":")[2].trim());
            context.write(new Text(name), new Text(id + ":" + rank));
        }   
    }

So my Output will have the concatenation of the id and rank field. I can see it in the output file if I print the value normally.

However, any split manipulation I execute throws aArrayOutOfBoundsException and I can't understand why. I even do a check if the value contains a ":" and it will print but it won't split. But when I don't make this check I get the exception.

Here is my reduce:

public void reduce(Text key, Iterable values, Context context) throws IOException, InterruptedException {

        List<String> elements = new ArrayList<String>();
        Text word = new Text();
        for (Text val : values) {
            if (val.toString().contains(":")) {
                String state = val.toString().split(":")[0];
                word.set(state);
            }
            context.write(key, word);
        }
    }

My output in my file looks like this:

Name   id:rank
Name   id:rank
Name   id:rank

...
...
...

But why can't I split off the id and rank?

Upvotes: 0

Views: 462

Answers (1)

N.Shrivastava
N.Shrivastava

Reputation: 94

To avoid ArrayOutOfBoundsException, check array size before getting value out of the array. Something like this will be more appropriate: 

    String[] temp = element.split(":"); 
    if(element.size()==2){
       String name = temp[0].trim(); 
       String id = temp[1].trim();
     }

Upvotes: 0

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