org.springframework.http.HttpHeaders#getFirst ( )源码实例Demo

@Override
protected Principal determineUser(ServerHttpRequest request, WebSocketHandler wsHandler, Map<String, Object> attributes) {
    Principal result = null;
    String authToken = null;
    HttpHeaders headers = request.getHeaders();

    if (log.isDebugEnabled()) {
        log.debug("Determining user...");
    }

    if (headers.containsKey(ServerConstants.X_AUTH_TOKEN)) {
        authToken = headers.getFirst(ServerConstants.X_AUTH_TOKEN);
        authenticate(authToken);
    } else if (attributes.containsKey(ServerConstants.X_AUTH_TOKEN)) {
        authToken = (String) attributes.get(ServerConstants.X_AUTH_TOKEN);

        authenticate(authToken);
    } else {
        result = super.determineUser(request, wsHandler, attributes);
    }

    return result;
}
 

@Test
public void httpHead() {
	String url = "http://localhost:" + this.port + "/text";
	HttpHeaders headers = getRestTemplate().headForHeaders(url);
	String contentType = headers.getFirst("Content-Type");
	assertNotNull(contentType);
	assertEquals("text/html;charset=utf-8", contentType.toLowerCase());
	assertEquals(3, headers.getContentLength());
}
 

private void assertHeaders(HttpHeaders headers, String key, boolean nullable, boolean quotaHeaders) {
    if (key != null && !key.startsWith("-")) {
      key = "-" + key;
    } else if (key == null) {
      key = "";
    }

    String quota = headers.getFirst(HEADER_QUOTA + key);
    String remainingQuota = headers.getFirst(HEADER_REMAINING_QUOTA + key);
    String limit = headers.getFirst(HEADER_LIMIT + key);
    String remaining = headers.getFirst(HEADER_REMAINING + key);
    String reset = headers.getFirst(HEADER_RESET + key);

    if (nullable) {
        if (quotaHeaders) {
            assertNull(quota);
            assertNull(remainingQuota);
        } else {
            assertNull(limit);
            assertNull(remaining);
        }
        assertNull(reset);
    } else {
        if (quotaHeaders) {
            assertNotNull(quota);
            assertNotNull(remainingQuota);
        } else {
            assertNotNull(limit);
            assertNotNull(remaining);
        }
        assertNotNull(reset);
    }
}
 

@Nullable
private static String getForwardedPrefix(ServerHttpRequest request) {
	HttpHeaders headers = request.getHeaders();
	String prefix = headers.getFirst("X-Forwarded-Prefix");
	if (prefix != null) {
		int endIndex = prefix.length();
		while (endIndex > 1 && prefix.charAt(endIndex - 1) == '/') {
			endIndex--;
		}
		prefix = (endIndex != prefix.length() ? prefix.substring(0, endIndex) : prefix);
	}
	return prefix;
}
 

@Nullable
private static String getForwardedPrefix(ServerHttpRequest request) {
	HttpHeaders headers = request.getHeaders();
	String prefix = headers.getFirst("X-Forwarded-Prefix");
	if (prefix != null) {
		int endIndex = prefix.length();
		while (endIndex > 1 && prefix.charAt(endIndex - 1) == '/') {
			endIndex--;
		}
		prefix = (endIndex != prefix.length() ? prefix.substring(0, endIndex) : prefix);
	}
	return prefix;
}
 

@Override
protected Mono<Boolean> doFilter(final ServerWebExchange exchange, final WebFilterChain chain) {
    final ServerHttpRequest request = exchange.getRequest();
    final HttpHeaders headers = request.getHeaders();
    final String upgrade = headers.getFirst("Upgrade");
    if (StringUtils.isNoneBlank(upgrade) && RpcTypeEnum.WEB_SOCKET.getName().equals(upgrade)) {
        return Mono.just(verify(request.getQueryParams()));
    }
    return Mono.just(true);
}
 

/**
 * Adapt this builder's scheme+host+port from the given headers, specifically
 * "Forwarded" (<a href="http://tools.ietf.org/html/rfc7239">RFC 7239</a>,
 * or "X-Forwarded-Host", "X-Forwarded-Port", and "X-Forwarded-Proto" if
 * "Forwarded" is not found.
 * @param headers the HTTP headers to consider
 * @return this UriComponentsBuilder
 * @since 4.2.7
 */
UriComponentsBuilder adaptFromForwardedHeaders(HttpHeaders headers) {
	String forwardedHeader = headers.getFirst("Forwarded");
	if (StringUtils.hasText(forwardedHeader)) {
		String forwardedToUse = StringUtils.tokenizeToStringArray(forwardedHeader, ",")[0];
		Matcher matcher = FORWARDED_HOST_PATTERN.matcher(forwardedToUse);
		if (matcher.find()) {
			adaptForwardedHost(matcher.group(1).trim());
		}
		matcher = FORWARDED_PROTO_PATTERN.matcher(forwardedToUse);
		if (matcher.find()) {
			scheme(matcher.group(1).trim());
		}
	}
	else {
		String hostHeader = headers.getFirst("X-Forwarded-Host");
		if (StringUtils.hasText(hostHeader)) {
			adaptForwardedHost(StringUtils.tokenizeToStringArray(hostHeader, ",")[0]);
		}

		String portHeader = headers.getFirst("X-Forwarded-Port");
		if (StringUtils.hasText(portHeader)) {
			port(Integer.parseInt(StringUtils.tokenizeToStringArray(portHeader, ",")[0]));
		}

		String protocolHeader = headers.getFirst("X-Forwarded-Proto");
		if (StringUtils.hasText(protocolHeader)) {
			scheme(StringUtils.tokenizeToStringArray(protocolHeader, ",")[0]);
		}
	}

	if ((this.scheme.equals("http") && "80".equals(this.port)) ||
			(this.scheme.equals("https") && "443".equals(this.port))) {
		this.port = null;
	}

	return this;
}
 

@Override
public Mono<Void> handle(WebSocketSession session) {
	HttpHeaders headers = session.getHandshakeInfo().getHeaders();
	String payload = "my-header:" + headers.getFirst("my-header");
	WebSocketMessage message = session.textMessage(payload);
	return session.send(Mono.just(message));
}
 

private HttpHeaders copyHeaders(HttpHeaders headers) {
    HttpHeaders tracingHeaders = new HttpHeaders();
    for (String key : tracingHeaderKeys) {
        String value = headers.getFirst(key);
        if (value != null) {
            tracingHeaders.add(key, value);
        }
    }
    return tracingHeaders;
}
 

private void addHeaders(Map<String, String> map, HttpHeaders headers,
		String... names) {
	if (headers != null) {
		for (String name : names) {
			String value = headers.getFirst(name);
			if (value != null) {
				map.put(name, value);
			}
		}
	}
}
 

private String getNextUrl(HttpHeaders headers) {
	String links = headers.getFirst("Link");
	for (String link : StringUtils.commaDelimitedListToStringArray(links)) {
		Matcher matcher = LINK_PATTERN.matcher(link.trim());
		if (matcher.matches() && "next".equals(matcher.group(2))) {
			return matcher.group(1);
		}
	}
	return null;
}
 

private MediaType getContentType(HttpHeaders headers) {
	String rawContentType = headers.getFirst("Content-Type");
	return (StringUtils.hasText(rawContentType) ? MediaType.parse(rawContentType) : null);
}
 

private HandshakeInfo createHandshakeInfo(URI url, DefaultNegotiation negotiation) {
	HttpHeaders responseHeaders = negotiation.getResponseHeaders();
	String protocol = responseHeaders.getFirst("Sec-WebSocket-Protocol");
	return new HandshakeInfo(url, responseHeaders, Mono.empty(), protocol);
}
 

private HandshakeInfo createHandshakeInfo(URI url, DefaultConfigurator configurator) {
	HttpHeaders responseHeaders = configurator.getResponseHeaders();
	String protocol = responseHeaders.getFirst("Sec-WebSocket-Protocol");
	return new HandshakeInfo(url, responseHeaders, Mono.empty(), protocol);
}
 

private HandshakeInfo createHandshakeInfo(URI url, Session jettySession) {
	HttpHeaders headers = new HttpHeaders();
	jettySession.getUpgradeResponse().getHeaders().forEach(headers::put);
	String protocol = headers.getFirst("Sec-WebSocket-Protocol");
	return new HandshakeInfo(url, headers, Mono.empty(), protocol);
}
 

@Override
protected boolean matchValue(HttpRequest request) {
	HttpHeaders httpHeaders = request.getHeaders();
	String headerValue = httpHeaders.getFirst(this.name);
	return ObjectUtils.nullSafeEquals(this.value, headerValue);
}
 

@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
		ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {

	mavContainer.setRequestHandled(true);
	if (returnValue == null) {
		return;
	}

	ServletServerHttpRequest inputMessage = createInputMessage(webRequest);
	ServletServerHttpResponse outputMessage = createOutputMessage(webRequest);

	Assert.isInstanceOf(HttpEntity.class, returnValue);
	HttpEntity<?> responseEntity = (HttpEntity<?>) returnValue;

	HttpHeaders outputHeaders = outputMessage.getHeaders();
	HttpHeaders entityHeaders = responseEntity.getHeaders();
	if (!entityHeaders.isEmpty()) {
		entityHeaders.forEach((key, value) -> {
			if (HttpHeaders.VARY.equals(key) && outputHeaders.containsKey(HttpHeaders.VARY)) {
				List<String> values = getVaryRequestHeadersToAdd(outputHeaders, entityHeaders);
				if (!values.isEmpty()) {
					outputHeaders.setVary(values);
				}
			}
			else {
				outputHeaders.put(key, value);
			}
		});
	}

	if (responseEntity instanceof ResponseEntity) {
		int returnStatus = ((ResponseEntity<?>) responseEntity).getStatusCodeValue();
		outputMessage.getServletResponse().setStatus(returnStatus);
		if (returnStatus == 200) {
			if (SAFE_METHODS.contains(inputMessage.getMethod())
					&& isResourceNotModified(inputMessage, outputMessage)) {
				// Ensure headers are flushed, no body should be written.
				outputMessage.flush();
				ShallowEtagHeaderFilter.disableContentCaching(inputMessage.getServletRequest());
				// Skip call to converters, as they may update the body.
				return;
			}
		}
		else if (returnStatus / 100 == 3) {
			String location = outputHeaders.getFirst("location");
			if (location != null) {
				saveFlashAttributes(mavContainer, webRequest, location);
			}
		}
	}

	// Try even with null body. ResponseBodyAdvice could get involved.
	writeWithMessageConverters(responseEntity.getBody(), returnType, inputMessage, outputMessage);

	// Ensure headers are flushed even if no body was written.
	outputMessage.flush();
}
 

private static com.squareup.okhttp.MediaType getContentType(HttpHeaders headers) {
	String rawContentType = headers.getFirst(HttpHeaders.CONTENT_TYPE);
	return (StringUtils.hasText(rawContentType) ?
			com.squareup.okhttp.MediaType.parse(rawContentType) : null);
}
 

private static okhttp3.MediaType getContentType(HttpHeaders headers) {
	String rawContentType = headers.getFirst(HttpHeaders.CONTENT_TYPE);
	return (StringUtils.hasText(rawContentType) ? okhttp3.MediaType.parse(rawContentType) : null);
}
 

@Override
public String getHeader(String key) {
	HttpHeaders headers = this.result.getRequestHeaders();
	return headers.containsKey(key) ? headers.getFirst(key) : null;
}