当我尝试使用非标准的HTTP方法（如PATCH）与URLConnection一起使用时：
HttpURLConnection conn = (HttpURLConnection) new URL("http://example.com").openConnection();
conn.setRequestMethod("PATCH");
我遇到了一个异常:
java.net.ProtocolException: Invalid HTTP method: PATCH
at java.net.HttpURLConnection.setRequestMethod(HttpURLConnection.java:440)
使用像Jersey这样的更高级别API会生成相同的错误。是否有解决方案来发出PATCH HTTP请求？
有很多好的答案，这是我的一个（不适用于jdk12）：
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Arrays;
import java.util.LinkedHashSet;
import java.util.Set;
public class SupportPatch {
public static void main(String... args) throws IOException {
allowMethods("PATCH");
HttpURLConnection conn = (HttpURLConnection) new URL("http://example.com").openConnection();
conn.setRequestMethod("PATCH");
}
private static void allowMethods(String... methods) {
try {
Field methodsField = HttpURLConnection.class.getDeclaredField("methods");
Field modifiersField = Field.class.getDeclaredField("modifiers");
modifiersField.setAccessible(true);
modifiersField.setInt(methodsField, methodsField.getModifiers() & ~Modifier.FINAL);
methodsField.setAccessible(true);
String[] oldMethods = (String[]) methodsField.get(null);
Set<String> methodsSet = new LinkedHashSet<>(Arrays.asList(oldMethods));
methodsSet.addAll(Arrays.asList(methods));
String[] newMethods = methodsSet.toArray(new String[0]);
methodsField.set(null/*static field*/, newMethods);
} catch (NoSuchFieldException | IllegalAccessException e) {
throw new IllegalStateException(e);
}
}
}
是的，有解决方法。使用
X-HTTP-Method-Override
。可以在POST请求中使用此标头来“伪造”其他HTTP方法。只需将X-HTTP-Method-Override标头的值设置为您实际要执行的HTTP方法即可。因此，请使用以下代码。
conn.setRequestProperty("X-HTTP-Method-Override", "PATCH");
conn.setRequestMethod("POST");
POST并且必须理解X-HTTP-Method-Override字段。请参见https://dev59.com/-l8e5IYBdhLWcg3w-OYn#46323891获取更好的实际修复方法。 - Feirell在OpenJDK中有一个无法修复的错误：https://bugs.openjdk.java.net/browse/JDK-7016595
然而，使用Apache Http-Components Client 4.2+可以实现此功能。它具有自定义的网络实现，因此可以使用所有标准的HTTP方法，如PATCH。它甚至还有一个支持patch方法的HttpPatch类。
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPatch httpPatch = new HttpPatch(new URI("http://example.com"));
CloseableHttpResponse response = httpClient.execute(httpPatch);
Maven坐标：
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.2+</version>
</dependency>
如果项目使用Spring/Gradle，以下解决方案可以解决问题。
在build.gradle中，添加以下依赖项;
compile('org.apache.httpcomponents:httpclient:4.5.2')
@Bean
public RestTemplate restTemplate() {
HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
requestFactory.setReadTimeout(600000);
requestFactory.setConnectTimeout(600000);
return new RestTemplate(requestFactory);
}
这个解决方案对我很有效。
implementation('org.apache.httpcomponents:httpclient') { because('java.net.HttpURLConnection不支持PATCH') } - M. Justinhttpclient依赖就足以支持Springboot。 - kosgeinsky在Java 11及以上版本中，您可以使用HttpRequest类来实现您想要的功能：
import java.net.http.HttpRequest;
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create(uri))
.method("PATCH", HttpRequest.BodyPublishers.ofString(message))
.header("Content-Type", "text/xml")
.build();
java.net.HttpURLConnection 的类。 - Carsten本文和相关问题中所述的反射在使用Oracle JRE上的HttpsURLConnection时无法正常工作，因为sun.net.www.protocol.https.HttpsURLConnectionImpl使用其DelegateHttpsURLConnection的java.net.HttpURLConnection中的method字段！
因此，一个完整的可行解决方案是：
private void setRequestMethod(final HttpURLConnection c, final String value) {
try {
final Object target;
if (c instanceof HttpsURLConnectionImpl) {
final Field delegate = HttpsURLConnectionImpl.class.getDeclaredField("delegate");
delegate.setAccessible(true);
target = delegate.get(c);
} else {
target = c;
}
final Field f = HttpURLConnection.class.getDeclaredField("method");
f.setAccessible(true);
f.set(target, value);
} catch (IllegalAccessException | NoSuchFieldException ex) {
throw new AssertionError(ex);
}
}
我遇到了相同的异常，在Groovy中编写了套接字解决方案，但我会将其翻译为Java并在答案中向您展示：
String doInvalidHttpMethod(String method, String resource){
Socket s = new Socket(InetAddress.getByName("google.com"), 80);
PrintWriter pw = new PrintWriter(s.getOutputStream());
pw.println(method +" "+resource+" HTTP/1.1");
pw.println("User-Agent: my own");
pw.println("Host: google.com:80");
pw.println("Content-Type: */*");
pw.println("Accept: */*");
pw.println("");
pw.flush();
BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
String t = null;
String response = "";
while((t = br.readLine()) != null){
response += t;
}
br.close();
return response;
}
我认为这在Java中能行。你需要更改服务器和端口号，记得也要更改Host头，而且可能还需要捕获一些异常。
\r\n，而不是println()提供的任何内容。 - user207421使用这个答案：
我创建了一个样本请求，并且完美运行：
public void request(String requestURL, String authorization, JsonObject json) {
try {
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setRequestMethod("POST");
httpConn.setRequestProperty("X-HTTP-Method-Override", "PATCH");
httpConn.setRequestProperty("Content-Type", "application/json");
httpConn.setRequestProperty("Authorization", authorization);
httpConn.setRequestProperty("charset", "utf-8");
DataOutputStream wr = new DataOutputStream(httpConn.getOutputStream());
wr.writeBytes(json.toString());
wr.flush();
wr.close();
httpConn.connect();
String response = finish();
if (response != null && !response.equals("")) {
created = true;
}
}
catch (Exception e) {
e.printStackTrace();
}
}
public String finish() throws IOException {
String response = "";
int status = httpConn.getResponseCode();
if (status == HttpURLConnection.HTTP_OK || status == HttpURLConnection.HTTP_CREATED) {
BufferedReader reader = new BufferedReader(new InputStreamReader(
httpConn.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
response += line;
}
reader.close();
httpConn.disconnect();
} else {
throw new IOException("Server returned non-OK status: " + status);
}
return response;
}
对于使用Spring restTemplate的人，如果你正在寻找详细的答案，那么你将会面临一个问题。
如果你使用SimpleClientHttpRequestFactory作为restTemplate的ClientHttpRequestFactory，则会遇到问题。
来自java.net.HttpURLConnection:
/* valid HTTP methods */
private static final String[] methods = {
"GET", "POST", "HEAD", "OPTIONS", "PUT", "DELETE", "TRACE"
};
由于不支持PATCH操作，因此来自同一类的此行代码将执行：
throw new ProtocolException("Invalid HTTP method: " + method);
最终我使用了与@hirosht在他的答案中建议的相同方法。
另一个肮脏的解决方案是反射：
private void setVerb(HttpURLConnection cn, String verb) throws IOException {
switch (verb) {
case "GET":
case "POST":
case "HEAD":
case "OPTIONS":
case "PUT":
case "DELETE":
case "TRACE":
cn.setRequestMethod(verb);
break;
default:
// set a dummy POST verb
cn.setRequestMethod("POST");
try {
// Change protected field called "method" of public class HttpURLConnection
setProtectedFieldValue(HttpURLConnection.class, "method", cn, verb);
} catch (Exception ex) {
throw new IOException(ex);
}
break;
}
}
public static <T> void setProtectedFieldValue(Class<T> clazz, String fieldName, T object, Object newValue) throws Exception {
Field field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
field.set(object, newValue);
}