我对PersonDTO具有以下定义：

public class PersonDTO
{
    private String id
    private String firstName;
    private String lastName;
    private String maritalStatus;
}

这是一个示例记录：

{
    "id": 1,
    "firstName": "John",
    "lastName": "Doe",
    "maritalStatus": "married"
}

现在，约翰·多伊离婚了。因此，我需要向该URL发送PATCH请求：

http://localhost:8080/people/1

带有以下请求正文：

{
    "maritalStatus": "divorced"
}

我不知道该怎么做。这是我到目前为止尝试过的：

// Create Person
PersonDTO person = new PersonDTO();
person.setMaritalStatus("Divorced");

// Create HttpEntity
final HttpEntity<ObjectNode> requestEntity = new HttpEntity<>(person);

// Create URL (for eg: localhost:8080/people/1)
final URI url = buildUri(id);

ResponseEntity<Void> responseEntity = restTemplate.exchange(url, HttpMethod.PATCH, requestEntity, Void.class);

这是上述问题：

1）由于我仅设置了MaritalStatus，因此其他字段均为null。因此，如果我打印出请求，它将看起来像这样：

{
    "id": null,
    "firstName": "null",
    "lastName": "null",
    "maritalStatus": "married" // I only need to update this field.
}

这是否意味着我必须先获得GET才能进行PATCH？

2）我得到以下堆栈跟踪：

08:48:52.717 ERROR c.n.d.t.s.PersonServiceImpl - Unexpected Exception  : 
org.springframework.web.client.ResourceAccessException: I/O error on PATCH request for "http://localhost:8080/people/1":Invalid HTTP method: PATCH; nested exception is java.net.ProtocolException: Invalid HTTP method: PATCH
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:580) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:545) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:466) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at com.sp.restclientexample..service.PersonServiceImpl.doPatch(PersonServiceImpl.java:75) ~[classes/:na]
    at com.sp.restclientexample..service.PatchTitle.itDoPatch(PatchTitle.java:53) [test-classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_20]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_20]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_20]
    at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_20]
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:73) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:224) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]
Caused by: java.net.ProtocolException: Invalid HTTP method: PATCH
    at java.net.HttpURLConnection.setRequestMethod(HttpURLConnection.java:440) ~[na:1.8.0_20]
    at sun.net.www.protocol.http.HttpURLConnection.setRequestMethod(HttpURLConnection.java:517) ~[na:1.8.0_20]
    at org.springframework.http.client.SimpleClientHttpRequestFactory.prepareConnection(SimpleClientHttpRequestFactory.java:209) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.http.client.SimpleClientHttpRequestFactory.createRequest(SimpleClientHttpRequestFactory.java:138) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.http.client.support.HttpAccessor.createRequest(HttpAccessor.java:76) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:565) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    ... 33 common frames omitted

感谢那些编写了客户端应用程序以使用Spring的RestTemplate使用Restful Web服务的人们的指针。

为了完整起见，我还声明我们将SpringDataRest用于后端静态Web服务。

SGB