ServletRegistrationBean Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletRegistrationBean.java lines 53–217

public class ServletRegistrationBean<T extends Servlet> extends DynamicRegistrationBean<ServletRegistration.Dynamic> {

	private static final String[] DEFAULT_MAPPINGS = { "/*" };

	private @Nullable T servlet;

	private Set<String> urlMappings = new LinkedHashSet<>();

	private boolean alwaysMapUrl = true;

	private int loadOnStartup = -1;

	private @Nullable MultipartConfigElement multipartConfig;

	/**
	 * Create a new {@link ServletRegistrationBean} instance.
	 */
	public ServletRegistrationBean() {
	}

	/**
	 * Create a new {@link ServletRegistrationBean} instance with the specified
	 * {@link Servlet} and URL mappings.
	 * @param servlet the servlet being mapped
	 * @param urlMappings the URLs being mapped
	 */
	public ServletRegistrationBean(T servlet, String... urlMappings) {
		this(servlet, true, urlMappings);
	}

	/**
	 * Create a new {@link ServletRegistrationBean} instance with the specified
	 * {@link Servlet} and URL mappings.
	 * @param servlet the servlet being mapped
	 * @param alwaysMapUrl if omitted URL mappings should be replaced with '/*'
	 * @param urlMappings the URLs being mapped
	 */
	public ServletRegistrationBean(T servlet, boolean alwaysMapUrl, String... urlMappings) {
		Assert.notNull(servlet, "'servlet' must not be null");
		Assert.notNull(urlMappings, "'urlMappings' must not be null");
		this.servlet = servlet;
		this.alwaysMapUrl = alwaysMapUrl;
		this.urlMappings.addAll(Arrays.asList(urlMappings));
	}

	/**
	 * Sets the servlet to be registered.
	 * @param servlet the servlet
	 */
	public void setServlet(T servlet) {
		Assert.notNull(servlet, "'servlet' must not be null");
		this.servlet = servlet;
	}

	/**
	 * Return the servlet being registered.
	 * @return the servlet
	 */
	public @Nullable T getServlet() {
		return this.servlet;
	}

	/**
	 * Set the URL mappings for the servlet. If not specified the mapping will default to
	 * '/'. This will replace any previously specified mappings.
	 * @param urlMappings the mappings to set
	 * @see #addUrlMappings(String...)
	 */
	public void setUrlMappings(Collection<String> urlMappings) {
		Assert.notNull(urlMappings, "'urlMappings' must not be null");
		this.urlMappings = new LinkedHashSet<>(urlMappings);
	}

	/**
	 * Return a mutable collection of the URL mappings, as defined in the Servlet
	 * specification, for the servlet.
	 * @return the urlMappings
	 */
	public Collection<String> getUrlMappings() {
		return this.urlMappings;
	}

	/**
	 * Add URL mappings, as defined in the Servlet specification, for the servlet.
	 * @param urlMappings the mappings to add
	 * @see #setUrlMappings(Collection)
	 */
	public void addUrlMappings(String... urlMappings) {
		Assert.notNull(urlMappings, "'urlMappings' must not be null");
		this.urlMappings.addAll(Arrays.asList(urlMappings));
	}

	/**
	 * Sets the {@code loadOnStartup} priority. See
	 * {@link ServletRegistration.Dynamic#setLoadOnStartup} for details.
	 * @param loadOnStartup if load on startup is enabled
	 */
	public void setLoadOnStartup(int loadOnStartup) {
		this.loadOnStartup = loadOnStartup;
	}

	/**
	 * Set the {@link MultipartConfigElement multi-part configuration}.
	 * @param multipartConfig the multipart configuration to set or {@code null}
	 */
	public void setMultipartConfig(@Nullable MultipartConfigElement multipartConfig) {
		this.multipartConfig = multipartConfig;
	}

	/**
	 * Returns the {@link MultipartConfigElement multi-part configuration} to be applied
	 * or {@code null}.
	 * @return the multipart config
	 */
	public @Nullable MultipartConfigElement getMultipartConfig() {
		return this.multipartConfig;
	}

	@Override
	protected String getDescription() {
		Assert.state(this.servlet != null, "Unable to return description for null servlet");
		return "servlet " + getServletName();
	}

	@Override
	protected ServletRegistration.Dynamic addRegistration(String description, ServletContext servletContext) {
		String name = getServletName();
		return servletContext.addServlet(name, this.servlet);
	}

	/**
	 * Configure registration settings. Subclasses can override this method to perform
	 * additional configuration if required.
	 * @param registration the registration
	 */
	@Override
	protected void configure(ServletRegistration.Dynamic registration) {
		super.configure(registration);
		String[] urlMapping = StringUtils.toStringArray(this.urlMappings);
		if (urlMapping.length == 0 && this.alwaysMapUrl) {
			urlMapping = DEFAULT_MAPPINGS;
		}
		if (!ObjectUtils.isEmpty(urlMapping)) {
			registration.addMapping(urlMapping);
		}
		registration.setLoadOnStartup(this.loadOnStartup);
		if (this.multipartConfig != null) {
			registration.setMultipartConfig(this.multipartConfig);
		}
	}

	/**
	 * Returns the servlet name that will be registered.
	 * @return the servlet name
	 */
	public String getServletName() {
		return getOrDeduceName(this.servlet);
	}

	@Override
	public String toString() {
		return getServletName() + " urls=" + getUrlMappings();
	}

}