Java Web Scraping Proxy

title: Java Web Scraping Proxy for compliant, high-throughput JVM data collection

description: Build a proxy-aware Java stack with JDK HttpClient or OkHttp, parse reliably with Jsoup, and ship dataset exports your teams can trust. Get geo-true sessions, tuned connection pools, and governance by default—no auth bypass, no paywall circumvention.

At scale, reliability is about identity, geography, and state—not just IP volume. Java’s modern HttpClient (JDK 11+) supports HTTP/2, TLS ALPN, and non-blocking I/O; paired with a disciplined proxy setup it delivers steady throughput and predictable tails.

• Proxy modes: HTTP CONNECT and SOCKS are both viable. Use ProxySelector for route rules (by host/port/ASN) and an Authenticator for Basic credentials or per-request Proxy-Authorization headers. Keep credentials in a secure store (KMS/HSM).
• Session model: short-lived identities for discovery; sticky identities for flows where cookies and locale matter (currency, language, ZIP). Rotate on milestones—filter changes, page depth, route transition—rather than every request.
• Timeouts & budgets: separate connect, handshake, and read deadlines; cap total call time. Treat retries differently for transport vs. throttling vs. semantic errors.
• Headers & locale: align Accept-Language, time zone hints, and IP geography to avoid price or catalog wobble. Keep a consistent User-Agent per run.
• Observability: log request IDs, proxy egress (city/ASN), status taxonomy (2xx/3xx/4xx/5xx), retry cause, and time-to-first-byte. Emit metrics to Micrometer/Prometheus.
• Compliance: collect only permitted public data; do not attempt to bypass authentication, paywalls, DRM, or anti-abuse controls.

OkHttp as a workhorse. OkHttp’s connection pooling and interceptors make it a great fit for proxy-rich workloads. Configure proxy and proxyAuthenticator, enforce callTimeout/connectTimeout/readTimeout, and attach interceptors for header normalization and retry policies. Keep pools per-origin when you need strict budgets, and prefer HTTP/2 for multiplexing where servers allow it.

Jsoup for resilient parsing. Normalize imperfect HTML into stable DOM access. Use CSS selectors for anchors (title, price, availability, pagination cursors) and add schema validation so malformed pages fail loudly.

Pool hygiene. Tune max idle per route, eviction of stale/idle connections, and keep-alive lifetimes to match server hints. Cap in-flight calls per host to prevent bursty soft blocks. Split pools by market when locale/state must not bleed across regions.

• Retries with backoff: jittered exponential backoff for 429/5xx; immediate retry on idempotent network timeouts; never retry non-idempotent posts.
• Caching & idempotency: reuse ETag/If-Modified-Since where allowed; content-address raw captures and collapse duplicates by hash.
• Cookie discipline: per-worker cookie jars; purge on rotation; pin SameSite semantics for deterministic flows.

Spring Boot microservices. Wrap fetch→parse→validate into a stateless service with rate limits, per-origin budgets, and health checks. Use WebClient (Reactor Netty) for async fan-out and emit Parquet/JSON to your lake with lineage (URL, timestamp, proxy info, hash).

Android data feeds. For on-device enrichment pipelines, OkHttp + WorkManager can stage controlled, low-rate pulls via a managed proxy. Respect battery/network constraints; cache aggressively; encrypt at rest; and avoid collecting PII unless strictly required and consented.

Enterprise backend integration. Produce governed outputs—schemas with versioning, nullable fields clarified, and currency/locale normalization. Stream to Kafka for downstream analytics and maintain replay with idempotent keys. Attach evidence thumbnails only when policy allows.

• Dashboards: success-per-10k calls, p50/p95 latency by market, retry rate, valid-page yield, dedupe %, and cost per 1k successful items.
• Playbooks: rotate markets with rising soft blocks, adjust pool sizes on tail growth, and quarantine noisy exits.

Pick vendors who disappear into your toolchain and stand behind outcomes—not pool size.

• JDK compatibility: certified support for 8/11/17/21; HTTP/2 and ALPN; TLS ciphers aligned with modern servers.
• SDK & build tooling: Maven/Gradle artifacts, example integrations for HttpClient/OkHttp, and first-class docs.
• Thread-safe handling: clear guidance on per-thread vs. shared clients, connection pool concurrency, and safe shutdown. Verified stability under load (no connection leaks, no stalled pools).
• Geo & ASN controls: city-level routing, ASN diversity, IPv4/IPv6, optional mobile/residential mixes for tougher routes.
• SLOs & evidence: ≥98% schema-valid items on stable routes, valid-page yield after retries, and provenance logs (request ID, route, hash).
• Governance: IP provenance, encryption in transit/at rest, minimal PII logging, retention windows, and incident kill-switches.
• Commercials: pricing per 1k successful items (not raw calls) and per deduped GB, with caps by market.

Bottom line. A proxy-aware Java stack—HttpClient or OkHttp for transport, Jsoup for resilient parsing, and disciplined pools/metrics for control—turns volatile pages into trustworthy, audit-ready datasets. Start with two markets for two weeks, wire KPIs to your BI, and benchmark success rate, tail latency, and cost against your current pipeline.