title: how does hadoop read input file?
body: <p>i have a csv file to analyze with hadoop mapreduce. I am wondering if hadoop will parse it line by line? if yes, i want to use string split by comma to get the fields  want to analyze. or is there other better method of parsing csv and feed it into hadoop? The file is 10 GB, comma delimited. I want to use java with hadoop. The parameter "value" of Tex type in the below map() method contains each line that is parsed in by Map/Reduce? - this is where I'm most confused about.</p>
  
  <p>this is my code:</p>
  
  <pre><code>public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
      try {
         String[] tokens = value.toString().split(",");
  
         String crimeType = tokens[5].trim();      
         int year = Integer.parseInt(tokens[17].trim()); 
  
         context.write(crimeType, year);
  
       } catch (Exception e) {...}
   }
  </code></pre>