A utility library to allow reading/writing of Tab separated tokens (CSV) to and from text files.
Historically, CSVReaderWriter provided this functionality via a bloated, inconsistent and semantically inaccurate interface which has now been deprecated in favour of the refactored Reader and Writer interfaces. Please browse CSVReaderWriter to understand the now deprecated api and the motivation behind deprecating the entire class.
Package io contains the newly refactored code alongwith javadocs to understand the method usage.
ReaderFactory and WriterFactory provide factory methods to instantiate concrete implementations of the new interfaces.
TabSeparatedReader and TabSeparatedWriter are concrete implementations of the Reader and Writer interfaces. They use the popular OpenCSV library available under Apache 2.0 license for implementing the core CSV parsing and serialisation/de-serialisation logic thereby benefiting from a robust and standard implementation that has been heavily tested in production code. It should be noted that RFC 4180 provides a de-facto standard for the CSV format and it is in our interest to look for existing solutions that implement this standard rather than having to implement and maintain it in-house.
An interface oriented design allows for providing various concrete implementations of the Reader and Writer interfaces (e.g. an implementation for storing meta data alogwith CSV values) and also allows for changing the underlying implementation without breaking the public api.
To read a file data.txt containing just some tab separated values, the following code should suffice:
com.CSV.io.Reader tabSeparatedReader = null;
try {
tabSeparatedReader = com.CSV.io.ReaderFactory.getTabSeparatedFileReader("data.txt");
List<String[]> tokens = tabSeparatedReader.readAll();
//consume tokens here ...
} catch (IOException e) {
// log exception
} finally {
try {
tabSeparatedReader.close();
} catch (Exception e) {
//log exception
}
}
To write a few lines worth of tab separated values to a file data.txt, one would implement the following:
com.CSV.io.Writer tabSeparatedWriter = null;
try {
tabSeparatedWriter = com.CSV.io.WriterFactory.getTabSeparatedFileWriter("data.txt");
//create a two lines worth of tokens that need to be tab separated and added to data.txt
ArrayList<String[]> lines = new ArrayList<String[]>();
lines.add(new String[] {
"abc", "xyz", "pqr"
});
lines.add(new String[] {
"123", "456", "789"
});
tabSeparatedWriter.append(lines);
//can append directly to the file as well
tabSeparatedWriter.append(new String[] {
"reader", "writer"
});
} catch (IOException e) {
// log exception
} finally {
try {
tabSeparatedWriter.close();
} catch (Exception e) {
}
}
The project uses gradle to build the java source files into a jar library and maven to push the generated jar artifacts to the maven local repository. Having maven and gradle already configured on your system is therefore a pre-requisite. It would also be simplest to install IntelliJ which has in-built support for gradle and maven.
Steps to follow on the Mac OSX command line (not tested on windows):
-
Clone the github repository as
git clone [email protected]:rahulmcs/csvreaderwriter.git. You may need to install git command line tools if not already installed. -
cd cvsreaderwriter -
./gradlew uploadArchives. This will build the library and publish the artifact to the local maven repository with following details:
Group Id: 'com.CSV'
artifact id: 'csvreaderwriter'
version: '1.1'
Once deployed, the locally published jar can then be used in your gradle or Maven based application project by adding the following dependency information to your build.gradle:
repositories {
mavenLocal()
}
dependencies {
compile 'com.CSV:csvreaderwriter:1.1'
}
Create a Sonatype Nexus repository so that the artifact can be published on to Maven central and can then be accessed by applications without needing to first publish the library to a local maven repository.