前言
每种编程语言里最常用的库恐怕是Http请求库了，如python里的requests包，nodejs里的request模块。
在Java世界里，也是百花齐放，山头林立。常用的有：
- HttpURLConnection: 最早的JDK提供的类
- Java 11提供的HttpClient
- Apache HttpComponents项目中的HTTPClient
- Square提供的OkHttpClient
- Spring 自带的WebClient
Apache HttpComponents
该组件提供了两个核心类：
- HttpCore: 更底层的传输处理类
- HttpClient：基于HttpCore实现的HTTP-compliant 处理类
JDK 11+ HTTP Client使用举例
Post同步的json数据：
java
public void invokePost() {
try {
String requestBody = prepareRequest();
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest
.newBuilder()
.uri(URI.create("https://reqbin.com/echo/post/json"))
.POST(HttpRequest.BodyPublishers.ofString(requestBody))
.header("Accept", "application/json")
.build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
}
private String prepareRequest() throws JsonProcessingException {
var values = new HashMap<String, String>() {
{
put("Id", "12345");
put("Customer", "Roger Moose");
put("Quantity", "3");
put("Price","167.35");
}
};
var objectMapper = new ObjectMapper();
String requestBody = objectMapper.writeValueAsString(values);
return requestBody;
}发送异步请求：
java
public void invoke() throws URISyntaxException {
HttpClient client = HttpClient.newBuilder()
.version(Version.HTTP_2)
.followRedirects(Redirect.NORMAL)
.build();
HttpRequest request = HttpRequest.newBuilder()
.uri(new URI(URLConstants.URL))
.GET()
.header(URLConstants.API_KEY_NAME, URLConstants.API_KEY_VALUE)
.timeout(Duration.ofSeconds(10))
.build();
client.sendAsync(request, BodyHandlers.ofString())
.thenApply(HttpResponse::body)
.thenAccept(System.out::println)
.join();
}HTTP Client包装库
cVurl
cVurl is an open-source wrapper for the Java HTTP client. It is written in Java 11 and can be used with any JDK 11.0.2 or newer.
java
public void cVurl() {
CVurl cVurl = new CVurl();
//POST
Result result = cVurl.post("https://api.imgflip.com/caption_image")
.queryParams(Map.of(
"template_id", "112126428",
"username", "test-user",
"password", "123test321",
"text0", "text0",
"text1", "text1"
))
.asObject(Result.class);
System.out.println("CVurl POST: " + result);
}它支持Compression、Multipart、Form data这些Java 11 HttpClient不具备的特性。
Avaje-HTTP
- Fluid API for building URLs and payload
- JSON marshaling using Avaje Jsonb/Jackson/Gson
- Light Feign-style interfaces via annotation processing.
- Request/Response Interception
- Authorization via Basic Auth or OAuth Bearer Tokens
- Async and sync API
个人建议
在实际项目中，设计符合自身项目需求的HTTP client接口，并基于JDK 11 HTTP client实现，独立于任何上述库。