TL;DR

This is a job search and recommmendation engine written in Java, implementing keyword extraction and content-based recommendation. It implements RESTful APIs using Java servlets, retrieves job descriptions using Github API and stores data in MySQL. Users can:

• Sign up and log in to the service
• Search nearby available job positions
• Save favorite job positions to account
• Get recommendated positions based on extracted keywords from favorites

Behind the Scenes

Java servlets are Java classes to handle RPC on the server side. Six Java servlets are created in this app: searchItem,recommendItem,login,logout,register,favoriteItem.

searchItemcommunicates with the GitHub Jobs API client to get available job positions. login,logout,register, andfavoriteItemcommunicates with the database to save users and postings. recommendItemdoes both to relay keywords from database to the search.

Keyword extraction uses TF-IDF algorithm implemented by MonkeyLearn API. TF (Term frequency) is the frequency of a word in a document. IDF (Inverse Document Frequency) is the importance of a word in all text. Final score = TF * IDF gives a measure to the importance of a particular word in this context.

A recommendation system seeks to predict the "rating" a user would give to an item. Content-based recommendation makes such prediction based on similarity shared between items themselves. This is usually used when we don't have enough user activity to begin with. In contrast, user-based recommendation makes the prediction based on similarity between users, while item-based recommendation will consider both similarity between items as well as the user's history of liking similar items.

Session is used to store a series of interations of the user currently visiting the webapp. When a user logs in, a session ID is assigned to the user. Users need to provide session ID to access resources that require authentication. HttpSession is an interface provided by the servlet API. HttpSession allows us to set attributes in key-value pairs that can be retrieved in future requests. The session ends when the user logs out or inactive after a predetermined period of time.

Dependencies

• MonkeyLearn API: https://monkeylearn.com/api/v3/#java
• GitHub Jobs API: https://jobs.github.com/api
• Apache Tomcat: http://tomcat.apache.org/
• MySQL Java connector: https://mvnrepository.com/artifact/mysql/mysql-connector-java