HttpClient 版本已經到 5.2.1 了. 在版本4中的一些方法已經變成 deprecated, 於是將之前的工具類升級一下, 順便把中間遇到的問題記錄一下 ...
Apache HttpClient 5
最近要在非SpringBoot環境調用OpenFeign介面, 需要用到httpclient, 註意到現在 HttpClient 版本已經到 5.2.1 了. 之前在版本4中的一些方法已經變成 deprecated, 於是將之前的工具類升級一下, 順便把中間遇到的問題記錄一下
基礎使用方法
首先參考Apache官方的快速開始 httpcomponents-client-5.2.x quickstart, 這是頁面上給的例子
Post請求
try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
HttpPost httpPost = new HttpPost("http://httpbin.org/post");
List<NameValuePair> nvps = new ArrayList<>();
nvps.add(new BasicNameValuePair("username", "vip"));
nvps.add(new BasicNameValuePair("password", "secret"));
httpPost.setEntity(new UrlEncodedFormEntity(nvps));
try (CloseableHttpResponse response2 = httpclient.execute(httpPost)) {
System.out.println(response2.getCode() + " " + response2.getReasonPhrase());
HttpEntity entity2 = response2.getEntity();
// do something useful with the response body
// and ensure it is fully consumed
EntityUtils.consume(entity2);
}
}
Get請求
try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
HttpGet httpGet = new HttpGet("http://httpbin.org/get");
try (CloseableHttpResponse response1 = httpclient.execute(httpGet)) {
System.out.println(response1.getCode() + " " + response1.getReasonPhrase());
HttpEntity entity1 = response1.getEntity();
// do something useful with the response body
// and ensure it is fully consumed
EntityUtils.consume(entity1);
}
}
替換 Deprecated 的 execute 方法
上面的例子可以正常運行, 但是在HttpClient5中, CloseableHttpResponse execute(ClassicHttpRequest request) 這個方法已經被標記為 Deprecated
@Deprecated
HttpResponse execute(ClassicHttpRequest var1) throws IOException;
@Deprecated
HttpResponse execute(ClassicHttpRequest var1, HttpContext var2) throws IOException;
@Deprecated
ClassicHttpResponse execute(HttpHost var1, ClassicHttpRequest var2) throws IOException;
@Deprecated
HttpResponse execute(HttpHost var1, ClassicHttpRequest var2, HttpContext var3) throws IOException;
取而代之的, 是這四個帶 HttpClientResponseHandler 參數的 execute 方法
<T> T execute(ClassicHttpRequest var1, HttpClientResponseHandler<? extends T> var2) throws IOException;
<T> T execute(ClassicHttpRequest var1, HttpContext var2, HttpClientResponseHandler<? extends T> var3) throws IOException;
<T> T execute(HttpHost var1, ClassicHttpRequest var2, HttpClientResponseHandler<? extends T> var3) throws IOException;
<T> T execute(HttpHost var1, ClassicHttpRequest var2, HttpContext var3, HttpClientResponseHandler<? extends T> var4) throws IOException;
}
這個 HttpClientResponseHandler 作為響應的處理方法, 裡面只有一個介面方法(要註意到這是一個函數式介面)
@FunctionalInterface
public interface HttpClientResponseHandler<T> {
T handleResponse(ClassicHttpResponse var1) throws HttpException, IOException;
}
JDK中提供了一個預設的實現, BasicHttpClientResponseHandler(基於 AbstractHttpClientResponseHandler)
public abstract class AbstractHttpClientResponseHandler<T> implements HttpClientResponseHandler<T> {
public AbstractHttpClientResponseHandler() {
}
public T handleResponse(ClassicHttpResponse response) throws IOException {
HttpEntity entity = response.getEntity();
if (response.getCode() >= 300) {
EntityUtils.consume(entity);
throw new HttpResponseException(response.getCode(), response.getReasonPhrase());
} else {
return entity == null ? null : this.handleEntity(entity);
}
}
public abstract T handleEntity(HttpEntity var1) throws IOException;
}
public class BasicHttpClientResponseHandler extends AbstractHttpClientResponseHandler<String> {
public BasicHttpClientResponseHandler() {
}
public String handleEntity(HttpEntity entity) throws IOException {
try {
return EntityUtils.toString(entity);
} catch (ParseException var3) {
throw new ClientProtocolException(var3);
}
}
public String handleResponse(ClassicHttpResponse response) throws IOException {
return (String)super.handleResponse(response);
}
}
這樣基礎的使用方式就改為了下麵的形式
public static void main(final String[] args) throws Exception {
final CloseableHttpClient httpClient = HttpClients.createDefault();
try (httpClient) {
final HttpGet httpGet = new HttpGet("https://www.baidu.com/home/other/data/weatherInfo");
final String responseBody = httpClient.execute(httpGet, new BasicHttpClientResponseHandler());
System.out.println(responseBody);
}
}
使用自定義的函數式方法處理響應
可以看到, 上面的 BasicHttpClientResponseHandler 是一個比較簡單的實現, 大於300的響應狀態碼直接拋出異常, 其它的讀出字元串. 這樣的處理方式對於更精細的使用場景是不夠的
- 需要根據響應狀態碼判斷時
- 需要對響應解析為Java類時
- 需要壓住異常, 統一返回類對象時
之前在 HttpClient4 時, 可以通過CloseableHttpResponse response = client.execute(httpRequest)
, 對 response 進行判斷, 現在response已經完全被handler 包裹, 需要通過自定義函數式方法處理響應, 看下麵的例子
首先定義一個響應結果類, 數據部分使用泛型
@Data
public class Client5Resp<T> implements Serializable {
private int code;
private String raw;
private T data;
public Client5Resp(int code, String raw, T data) {
this.code = code;
this.raw = raw;
this.data = data;
}
}
然後對響應結果自定義 handler, 因為是函數式介面, 所以很方便在方法中直接定義, 處理的邏輯是:
- 如果 T 泛型為String, 直接將 body 作為數據返回
- 其它的 T 泛型, 用 Jackson 解開之後返回
- 將 status code 一併返回
private static <T> Client5Resp<T> httpRequest(
TypeReference<T> tp,
HttpUriRequest httpRequest) {
try (CloseableHttpClient client = HttpClients.createDefault()) {
Client5Resp<T> resp = client.execute(httpRequest, response -> {
if (response.getEntity() != null) {
String body = EntityUtils.toString(response.getEntity());
if (tp.getType() == String.class) {
return new Client5Resp<>(response.getCode(), body, (T)body);
}
// 當需要區分更多類型時可以增加定義
else {
T t = JacksonUtil.extractByType(body, tp);
return new Client5Resp<>(response.getCode(), body, t);
}
} else {
return new Client5Resp<>(response.getCode(), null, null);
}
});
log.info("rsp:{}, body:{}", resp.getCode(), resp.getRaw());
return resp;
} catch (IOException|NoSuchAlgorithmException|KeyStoreException|KeyManagementException e) {
// 當異常也需要返回 Client5Resp 類型對象時可以在catch中封裝
log.error(e.getMessage(), e);
}
return null;
}
自定義請求設置和Header
首先是超時設置
RequestConfig defaultRequestConfig = RequestConfig.custom()
.setConnectionRequestTimeout(60, TimeUnit.SECONDS)
.setResponseTimeout(60, TimeUnit.SECONDS)
.build();
然後是 Header
List<Header> headers = List.of(
new BasicHeader(HttpHeaders.CONTENT_TYPE, "application/json"),
new BasicHeader(HttpHeaders.ACCEPT, "application/json"));
在 HttpGet/HttpPost 中設置
HttpGet httpGet = new HttpGet(...);
if (headers != null) {
for (Header header : headers) {
httpGet.addHeader(header);
}
}
RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig).build();
httpGet.setConfig(requestConfig);
自定義 HttpClient 增加 SSL TrustAllStrategy
在 HttpClient5 中, 增加 SSL TrustAllStrategy 的方法也有變化, 這是獲取 CloseableHttpClient 的代碼
final RequestConfig defaultRequestConfig = RequestConfig.custom()
.setConnectionRequestTimeout(60, TimeUnit.SECONDS)
.setResponseTimeout(60, TimeUnit.SECONDS)
.build();
final BasicCookieStore defaultCookieStore = new BasicCookieStore();
final SSLContext sslcontext = SSLContexts.custom()
.loadTrustMaterial(null, new TrustAllStrategy()).build();
final SSLConnectionSocketFactory sslSocketFactory = SSLConnectionSocketFactoryBuilder.create()
.setSslContext(sslcontext).build();
final HttpClientConnectionManager cm = PoolingHttpClientConnectionManagerBuilder.create()
.setSSLSocketFactory(sslSocketFactory).build();
return HttpClients.custom()
.setDefaultCookieStore(defaultCookieStore)
.setDefaultRequestConfig(defaultRequestConfig)
.setConnectionManager(cm)
.evictExpiredConnections()
.build();
增加 Http Proxy
固定的 Proxy
在 HttpClient5 中, RequestConfig.Builder.setProxy()方法已經 Deprecated
@Deprecated
public RequestConfig.Builder setProxy(HttpHost proxy) {
this.proxy = proxy;
return this;
}
需要使用 HttpClientBuilder.setRoutePlanner(HttpRoutePlanner routePlanner) 進行設置, 和SSL一起, 獲取client的代碼變成
final HttpHost proxy = new HttpHost(proxyHost, proxyPort);
final DefaultProxyRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxy);
return HttpClients.custom()
.setDefaultCookieStore(defaultCookieStore)
.setDefaultRequestConfig(defaultRequestConfig)
.setRoutePlanner(routePlanner)
.setConnectionManager(cm)
.evictExpiredConnections()
.build();
如果需要用戶名密碼, 需要再增加一個 CredentialsProvider, 變成
final HttpHost proxy = new HttpHost(proxyHost, proxyPort);
final DefaultProxyRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxy);
final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();
credsProvider.setCredentials(
new AuthScope(proxyHost, proxyPort),
new UsernamePasswordCredentials(authUser, authPasswd.toCharArray()));
return HttpClients.custom()
.setDefaultCookieStore(defaultCookieStore)
.setDefaultRequestConfig(defaultRequestConfig)
.setDefaultCredentialsProvider(credsProvider)
.setRoutePlanner(routePlanner)
.setConnectionManager(cm)
.evictExpiredConnections()
.build();
動態 Proxy
如果需要隨時切換 proxy, 需要自己實現一個 HttpRoutePlanner
public static class DynamicProxyRoutePlanner implements HttpRoutePlanner {
private DefaultProxyRoutePlanner planner;
public DynamicProxyRoutePlanner(HttpHost host){
planner = new DefaultProxyRoutePlanner(host);
}
public void setProxy(HttpHost host){
planner = new DefaultProxyRoutePlanner(host);
}
public HttpRoute determineRoute(HttpHost target, HttpContext context) throws HttpException {
return planner.determineRoute(target, context);
}
}
然後在代碼中進行切換
HttpHost proxy = new HttpHost("127.0.0.1", 1080);
DynamicProxyRoutePlanner routePlanner = new DynamicProxyRoutePlanner(proxy);
CloseableHttpClient httpclient = HttpClients.custom()
.setRoutePlanner(routePlanner)
.build();
// 換代理
routePlanner.setProxy(new HttpHost("192.168.0.1", 1081));
構造 Multipart 文件上傳請求
首先是構造 HttpEntity 的方法, 這個方法中設置請求為 1個文件 + 多個隨表單參數
public static HttpEntity httpEntityBuild(NameValuePair fileNvp, List<NameValuePair> nvps) {
File file = new File(fileNvp.getValue());
MultipartEntityBuilder builder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.STRICT);
if (nvps != null && nvps.size() > 0) {
for (NameValuePair nvp : nvps) {
builder.addTextBody(nvp.getName(), nvp.getValue(), ContentType.DEFAULT_BINARY);
}
}
builder.addBinaryBody(fileNvp.getName(), file, ContentType.DEFAULT_BINARY, fileNvp.getValue());
return builder.build();
}
請求流程
// 構造一個文件參數, 其它參數留空
NameValuePair fileNvp = new BasicNameValuePair("sendfile", filePath);
HttpEntity entity = httpEntityBuild(fileNvp, null);
HttpPost httpPost = new HttpPost(api);
httpPost.setEntity(entity);
try (CloseableHttpClient client = getClient(...)) {
Client5Resp<T> resp = client.execute(httpPost, response->{
...
});
註意: 在使用 HttpMultipartMode 時對 HttpEntity 設置 Header 要謹慎, 因為 HttpClient 會對 Content-Type增加 Boundary 尾碼, 而這個是服務端判斷文件邊界的重要參數. 如果設置自定義 Header, 需要檢查 boundary 是否正確生成. 如果沒有的話需要自定義 Content-Type 將 boundary 加進去, 並且通過 EntityBuilder.setBoundary() 將自定義的 boundary 值傳給 HttpEntity.