This article explores Fastjson, a high-performance JSON processing library by Alibaba, offering 40% faster serialization than Jackson and 80% faster than Gson. It covers its core features, including performance optimizations and a comprehensive feature matrix. The article also delves into integrating Fastjson with Spring Boot, showcasing configuration examples and advanced application techniques like JSONPath queries and custom serialization/deserialization. Additionally, it provides security best practices and performance optimization strategies for handling large files and sensitive data.