Mastering Ant‑Style Path Patterns in Spring MVC and Spring Security

1. Introduction

In many Spring tutorials we encounter uri support for Ant‑style patterns, which are frequently mentioned in both Spring MVC and Spring Security. Understanding Ant patterns is essential for mastering URL matching in these frameworks.

2. Ant Style

The Ant style is a path‑matching expression used to match uri strings. It works similarly to regular expressions but is limited to path matching.

3. Ant Wildcards

Ant provides three wildcard symbols: ? matches any single character. * matches zero or more characters within a single directory level. ** matches zero or more directory levels.

3.1 Ant Wildcard Example

3.2 Longest‑Match Principle

When a uri matches multiple patterns, the one with the most characters wins (the longest match). For example, /ant/a/path matches both /**/path and /ant/*/path; the latter is chosen because it has more characters.

4. Ant Style in Spring MVC and Spring Security

4.1 Spring MVC

In a Spring MVC controller you can use Ant patterns in the mapping annotation:

@GetMapping("/?ant")
public String ant() {
    return "ant";
}

Any valid uri character can replace the ? wildcard, e.g., /bant matches the pattern.

4.2 Spring Security

Spring Security uses Ant patterns in antMatchers to control resource access:

public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
            .withUser("admin").password("admin").roles("USER");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
            .antMatchers("/index.html", "/static/**").permitAll()
            .anyRequest().authenticated();
    }
}

The antMatchers method uses Ant wildcards to specify which URLs are publicly accessible.

5. Summary

Ant‑style path patterns are simple yet powerful tools for URI configuration, routing, and access control in web development. Mastering them is a must‑have skill for backend developers working with Spring MVC and Spring Security.