Chris Zhang
Verified Expert in Engineering
Software Engineer and Developer
Ontario, CA, United States
Toptal member since August 23, 2023
Chris is a senior back-end Java developer with almost ten years of experience building efficient, scalable back-end services for eCommerce sites and the healthcare industry. He is also a fast learner with a deep knowledge of Java, Spring Boot, RESTful APIs, and microservices architecture. Chris is also proficient at implementing secure authentication and authorization mechanisms, ensuring data integrity and protection, and leveraging his strong analytical and problem-solving skills.
Portfolio
Experience
- Spring - 7 years
- Java 8 - 7 years
- RESTful Web Services - 7 years
- CI/CD Pipelines - 6 years
- Docker - 5 years
- Elasticsearch - 4 years
- Python - 2 years
- HL7 FHIR Standard - 2 years
Preferred Environment
Shell, Windows, Slack, IntelliJ IDEA, Postman, SoapUI, Mirth Connect, AWS Glue, AWS Lambda, GitLab CI/CD
The most amazing...
...back-end service I've created from scratch is for Yamibuy's eCommerce site, one of the most successful apps in Asia.
Work Experience
Senior Java Software Engineer
Shoobilee, Inc.
- Built a Java RESTful web service using Spring Boot, PostgreSQL, and Redis.
- Implemented a payment system by integrating PayPal, Chase Paymentech Orbital Gateway, and a customer subscription system.
- Wrote a shell script to deploy the back-end service to Amazon EC2.
Senior Java Software Engineer
Akido Labs
- Maintained a Java RESTful web service providing healthcare information based on the HAPI FHIR library. I introduced new features, endpoints, and bug fixes.
- Managed an ETL pipeline using AWS Glue with PySpark and Apache Airflow with Python. I also leveraged Amazon CloudWatch for monitoring purposes and AWS Lambda to trigger the AWS Glue jobs and move files to FTP and Amazon S3.
- Supported a data pipeline using Mirth Connect by JavaScript.
- Built a NestJS common package for connecting and using RabbitMQ as a message queue service.
Senior Java Developer and Team Leader
Unitedstars International Ltd.
- Designed and built the RESTful web service from scratch with Spring, RESTEasy, MyBatis, and MySQL to distribute to ctrip.com and Alibaba.
- Managed the project's progress and coordinated the team's daily work, coding the central part of the system and reviewing code from members' pull requests.
- Developed and designed a responsive and efficient search system using Elasticsearch.
- Handled the static data integration of several hotel providers, including data mapping, and integrated APIs from popular hotel providers into our hotel system.
- Built the cache system using Redis for a better user experience.
Senior Software Engineer
Yami
- Designed and built the RESTful service for Yamibuy, a popular online shopping website, fitting it into dynamic usages for mobile and web applications and leveraging Spring Boot, MyBatis, and MySQL.
- Built a payment service for Yamibuy by integrating it with Chase Bank's gateway and PayPal.
- Created an intelligent and fast search service with Elasticsearch for many products in several categories.
- Developed a distributed system using NGINX as the load balancer and MySQL for replication.
- Implemented a read-and-write split and a master-slave sync system, using AWS for web service deployment and website hosting and Apache Kafka as a messaging system.
Senior Software Engineer
CIeNET Technologies
- Participated in developing and maintaining a B/S network system made by Ericsson. This system evolved into two distinct approaches to managing network elements made by different manufacturers, such as Redback and Marconi.
- Implemented a JBoss application server using Java EE and Enterprise Java Beans (EJB) technology to manage the end-to-end service and communication over various network elements.
- Gained experience in the Spring framework and CI/CD pipelines.
Software Developer
Beijing JBridge Information Technology
- Acted as a design leader, managing a team of ten members.
- Developed a major module for a web management system, transforming it from Apache Struts and Oracle into a new system based on Seam, MyBatis, and NonStop.
- Built a management system for supermarket stock and designed a batch system using shells, scripts, and SQL. Handled code design, code development, and function testing.
- Participated in maintaining a client-server management system for some hospitals based on VB.NET, handling code development and testing.
- Contributed to developing a logistics system based on Java EE using JSP, C, JCL, and Oracle databases. Handled preliminary design, detailed design, test case design, code development, and function testing.
- Maintained a logistics system based on COBOL, handling preliminary design, detailed design, test case design, code development, function testing, technical support, and training.
Experience
A RESTful Back-end Service for Yamibuy
A Data Pipeline for a Healthcare Group
A Search Engine for Yamibuy
New Mirth Pipeline for an Orders Interface
• Configured inbound and outbound network locations for the processing of order and result messages.
• Built an interface to output ORM messages to specified network locations.
• Built an interface to process incoming HL7 result messages that contain discrete results and PDF attachments.
Education
Bachelor's Degree in Computer Science
Hebei University of Technology - Hebei, China
Skills
Libraries/APIs
Mirth Connect, RESTEasy, REST APIs, MyBatis, PySpark, Terragrunt
Tools
Shell, IntelliJ IDEA, Postman, SoapUI, AWS Glue, GitLab CI/CD, Git, RabbitMQ, Slack, NGINX, Apache Airflow, Jenkins, CircleCI, Amazon CloudWatch, JCL, Kibana
Languages
Java, COBOL, Java 8, C#, Python, SQL, XML, C++, VB.NET, C, TypeScript
Frameworks
Spring, Hibernate, Spring Boot, Spring Microservice, NestJS, Seam
Paradigms
HL7 FHIR Standard
Platforms
Windows, Java EE (Jakarta EE), Amazon EC2, Docker, Amazon Web Services (AWS), AWS Lambda, Apache Kafka, Oracle
Storage
Elasticsearch, PostgreSQL, Databases, JSON, MySQL, Couchbase, Amazon DynamoDB, Data Pipelines, Amazon S3 (AWS S3), Redis
Other
CI/CD Pipelines, RESTful Services, RESTful Web Services, Back-end, RESTful Microservices, Shell Scripting, IP Networks, Network Management Stations (NMS), Enterprise Java Beans (EJB), Chase Paymentech, OAuth, Amazon Route 53, Computer Science, FTP, Infrastructure as Code (IaC), HL7, DICOM - SR & HL7
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