Thursday, February 16, 2012

Spring Batch Tutorial (Part 1)

In this tutorial, we will create a simple Spring Batch application to demonstrate how to process a series of jobs where the primary purpose is to import a lists of comma-delimited and fixed-length records. In addition, we will add a web interface using Spring MVC to teach how to trigger jobs manually, and so that we can visually inspect the imported records. In the data layer, we will use JPA, Hibernate, and MySQL.

Part 1: Introduction and Functional Specs
Part 2: Java classes
Part 3: XML configuration
Part 4: Running the Application

Dependencies

Spring core 3.1.0.RELEASE
Spring Batch 2.1.8.RELEASE
See pom.xml for details

Github
To access the source code, please visit the project's Github repository (click here)

Functional Specs

Before we start, let's define the application's specs as follows:

Import a list of comma-delimited records
Import a list of fixed-length records
Import a list of mixed-type records
Jobs must be triggered using a web interface
Display the imported records in a web interface
Each record represents a user and its associated access levels

Here's our Use Case diagram:

[User]-(Import job1)
[User]-(Import job2) 
[User]-(Import job3) 
[User]-(View records)

The CSV Files

To visualize what we want to do, let's examine first the files that we plan to import:

User Files

user1.csv
This file contains comma-separated value (CSV) records representing User records. Each line has the following tokens: username, first name, last name, password.

user2.csv
This file contains fixed-length records representing User records. Each line has the following tokens: username(positions 1-5), first name(6-9), last name(10-16), password(17-25).

user2.csv
This file contains comma-separated value and fixed-length records representing User records. Each line has the following tokens: username, first name, last name, password.

This file contains two types of CSV-records:

DELIMITED-RECORD-A: uses the standard comma delimiter
DELIMITED-RECORD-B: uses | delimiter

It also contains two types of fixed-length records:

FIXED-RECORD-A: username(16-20), first name(21-25), last name(26-31), password(32-40)
FIXED-RECORD-B: username(16-21), first name(22-27), last name(28-33), password(35-42)

Role Files

role1.csv
This file contains comma-separated value (CSV) records representing Role records. Each line has the following tokens: username and access level.

role2.csv
This file contains fixed-length records representing Role records. Each line has the following tokens: username and access level.

role3.csv
This file contains comma-separated value (CSV) records representing Role records. Each line has the following tokens: username and access level.

By now you should have a basic idea of the file formats that we will be importing. You must realize that all we want to do is import these files and display them on a web interface.

Diagrams

Here's the Class diagram:

# Cool UML Diagram
[User|id;firstName;lastName;username;password;role{bg:orange}]1--1> [Role|id;role{bg:green}]

Here's the Activity Diagram:

(start)->import->success->(Show Success Alert)->|a|->(end),
fail->(Show Fail Alert)->|a|,
view->(Show Records)->|a|->(end)

Screenshots

Let's preview how the application will look like after it's finished. This is also a good way to clarify further the application's specs.

Entry page
The entry page is the primary page that users will see. It contains a table showing user records and four buttons for adding, editing, deleting, and reloading data. All interactions will happen in this page.