#optional code explainers

java

public URI buildSearchUri(String query, int page, int size, List<String> tags) {
    UriComponentsBuilder builder = UriComponentsBuilder
            .fromUriString("https://api.example.com")
            .path("/v2/products/search")

Building URIs safely with UriComponentsBuilder in Spring

url-building builder-pattern encoding

Intermediate 5 steps

java

public final class AccessLogParser {
 
    private static final Pattern LINE = Pattern.compile(
        "^(?<ip>\\S+) \\S+ \\S+ \\[(?<time>[^\\]]+)\\] "

Parsing Apache access logs in Java

regex named-groups parsing

Intermediate 7 steps

java

public final class QueryParams {
 
    private final Map<String, List<String>> params;

Parsing and building URL query strings in Java

parsing multimap url-encoding

Intermediate 9 steps

java

public final class ShippingAddress {
    private final String recipient;
    private final String line1;
    private final String line2;

Building immutable objects with the Builder pattern

builder-pattern immutability validation

Intermediate 7 steps

java

@RestController
@RequestMapping("/api/users")
public class UserController {

How a Spring REST controller maps users

rest-api dependency-injection dto-mapping

Intermediate 7 steps