Existe-t-il une bonne façon de créer une URL?

Vous pouvez utiliser Apache URIBuilder

Exemple de code: Exemple complet d'Apache

URIBuilder builder = new URIBuilder()
    .setScheme("http")
    .setHost("apache.org")
    .setPath("/shindig")
    .addParameter("hello world", "foo&bar")
    .setFragment("foo");
builder.toString();

Sortie: http://apache.org/shindig?hello+monde=foo%26bar#foo

Vous pouvez aussi utiliser le printemps UriComponentsBuilder

UriComponentsBuilder
    .fromUriString(baseUrl)
    .queryParam("name", name)
    .queryParam("surname", surname)
    .build().toUriString();

J'aime la suggestion de @Jeroen mais elle n'a pas tout à fait fait tout ce que je voulais donc, en utilisant son idée de rassembler les pièces ensemble puis en utilisant un URI pour développer le résultat final, j'ai mis en place cette solution qui semble faire ce que je veux:

public class URLBuilder {
  // The scheme - http
  private String scheme = null;
  // The user - user
  private String user = null;
  // The host - example.com
  private String host = null;
  // The port - 8080
  private int port = -1;
  // The paths - /Path/To/Somewhere/index.jsp
  private final ArrayList<String> paths = new ArrayList<String>();
  // The parameters - ?a=b&c=d
  private final ArrayList<Pair<String, String>> queries = new ArrayList<Pair<String, String>>();
  // The fragment - #n
  private String fragment = null;

  public URLBuilder addQuery(String name, String value) {
    queries.add(new Pair(name, value));
    return this;
  }

  public URLBuilder addQuery(String name, long value) {
    addQuery(name, String.valueOf(value));
    return this;
  }

  public URLBuilder addQuery(String name, File file) {
    addQuery(name, file.toURI().getPath());
    return this;
  }

  public URLBuilder addPath(String path) {
    paths.add(path);
    return this;
  }

  @Override
  public String toString() {
    // Build the path.
    StringBuilder path = new StringBuilder();
    for (String p : paths) {
      path.append("/").append(p);
    }
    // Build the query.
    StringBuilder query = new StringBuilder();
    String sep = "";
    for (Pair<String, String> p : queries) {
      query.append(sep).append(p.p).append("=").append(p.q);
      sep = "&";
    }
    String url = null;
    try {
      URI uri = new URI(
              scheme,
              user,
              host,
              port,
              path.length() > 0 ? path.toString() : null,
              query.length() > 0 ? query.toString() : null,
              fragment);
      url = uri.toString();
    } catch (URISyntaxException ex) {
      Logger.getLogger(URLBuilder.class.getName()).log(Level.SEVERE, null, ex);
    }

    return url;
  }

  /**
   * @param host the host to set
   * @return this
   */
  public URLBuilder setHost(String host) {
    this.host = host;
    return this;
  }

  /**
   * @param scheme the scheme to set
   * @return this
   */
  public URLBuilder setScheme(String scheme) {
    this.scheme = scheme;
    return this;
  }

  /**
   * @param user the user to set
   * @return this
   */
  public URLBuilder setUser(String user) {
    this.user = user;
    return this;
  }

  /**
   * @param port the port to set
   * @return this
   */
  public URLBuilder setPort(int port) {
    this.port = port;
    return this;
  }

  /**
   * @param fragment the fragment to set
   * @return this
   */
  public URLBuilder setFragment(String fragment) {
    this.fragment = fragment;
    return this;
  }

  public static void main(String args[]) {
    try {
      URLBuilder url = new URLBuilder();
      System.out.println(url.toString());
      url.setFragment("fragment");
      System.out.println(url.toString());
      url.setHost("host.com");
      System.out.println(url.toString());
      url.addPath("APath");
      System.out.println(url.toString());
      url.addPath("AnotherPath");
      System.out.println(url.toString());
      url.addQuery("query1", "param1");
      System.out.println(url.toString());
      url.addQuery("query 2", "param 2");
      System.out.println(url.toString());
      url.addQuery("file", new File("Hello World.txt"));
      System.out.println(url.toString());
    } catch (Throwable t) {
      t.printStackTrace(System.err);
    }
  }

}

Recommandations

private final String BASE_URL = Properties.getProperty("base-url");

private Map propertiesMap; // = new HashMap<String,String>();

Et dans le code pour construire l'URL.

public String buildURL(){
    StringBuilder builder = new StringBuilder();
    builder.append(BASE_URL);
    //for each property, append it

    return builder.toString();

}