Creating a read/process/write step

A read/process/write step is a common type of step where some data is read somewhere, processed in some way, and finally, saved somewhere else. In this recipe, we'll read a CSV file of users, increment their age, and save the modified users in a database as shown in the following image:

Getting ready

This is our CSV file of users, input_data.txt:

Merlin, 333
Arthur, 37
Lancelot, 35
Tristan, 20
Iseult, 22
Mark, 56

For each line of the CSV file, we'll create a User object. So, make sure that the User class exists:

public class User {
  private String firstName;
  private int age;
…
}

Each User object will be saved in the database. Make sure that the user table exists:

CREATE TABLE user  (
    id BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
  first_name TEXT,
  age INT
);

How to do it…

Follow these steps to process the CSV file:

1. In the Spring Batch configuration class, add a method returning a LineMapper object, which generates an User object from a line in the CSV file...