一尘不染

spring:使用ResponseEntity返回空的HTTP响应 不起作用

spring-mvc

我们正在使用Spring(4.1.1。)实现REST
API。对于某些HTTP请求,我们希望返回一个没有主体的头作为响应。但是,使用ResponseEntity<Void>似乎无效。通过MockMvc测试调用时,返回406(不可接受)。使用ResponseEntity<String>不带参数的值(new ResponseEntity<String>( HttpStatus.NOT_FOUND ))工作正常。

方法:

@RequestMapping( method = RequestMethod.HEAD, value = Constants.KEY )
public ResponseEntity<Void> taxonomyPackageExists( @PathVariable final String key ) {

    LOG.debug( "taxonomyPackageExists queried with key: {0}", key ); //$NON-NLS-1$

    final TaxonomyKey taxonomyKey = TaxonomyKey.fromString( key );

    LOG.debug( "Taxonomy key created: {0}", taxonomyKey ); //$NON-NLS-1$

    if ( this.xbrlInstanceValidator.taxonomyPackageExists( taxonomyKey ) ) {

        LOG.debug( "Taxonomy package with key: {0} exists.", taxonomyKey ); //$NON-NLS-1$

        return new ResponseEntity<Void>( HttpStatus.OK );

    } else {

        LOG.debug( "Taxonomy package with key: {0} does NOT exist.", taxonomyKey ); //$NON-NLS-1$

        return new ResponseEntity<Void>( HttpStatus.NOT_FOUND );
    }

}

测试用例(TestNG):

public class TaxonomyQueryControllerTest {

private XbrlInstanceValidator   xbrlInstanceValidatorMock;
private TaxonomyQueryController underTest;
private MockMvc                 mockMvc;

@BeforeMethod
public void setUp() {
    this.xbrlInstanceValidatorMock = createMock( XbrlInstanceValidator.class );
    this.underTest = new TaxonomyQueryController( this.xbrlInstanceValidatorMock );
    this.mockMvc = MockMvcBuilders.standaloneSetup( this.underTest ).build();
}

@Test
public void taxonomyPackageDoesNotExist() throws Exception {
    // record
    expect( this.xbrlInstanceValidatorMock.taxonomyPackageExists( anyObject( TaxonomyKey.class ) ) ).andStubReturn(
            false );

    // replay
    replay( this.xbrlInstanceValidatorMock );

    // do the test
    final String taxonomyKey = RestDataFixture.taxonomyKeyString;

    this.mockMvc.perform( head( "/taxonomypackages/{key}", taxonomyKey ).accept( //$NON-NLS-1$
            MediaType.APPLICATION_XML ) ).andExpect( status().isNotFound() );

}

}

此堆栈跟踪失败:

FAILED: taxonomyPackageDoesNotExist
java.lang.AssertionError: Status expected:<404> but was:<406>
at org.springframework.test.util.AssertionErrors.fail(AssertionErrors.java:60)
at org.springframework.test.util.AssertionErrors.assertEquals(AssertionErrors.java:89)
at org.springframework.test.web.servlet.result.StatusResultMatchers$10.match(StatusResultMatchers.java:652)
at org.springframework.test.web.servlet.MockMvc$1.andExpect(MockMvc.java:153)
at de.zeb.control.application.xbrlstandalonevalidator.restservice.TaxonomyQueryControllerTest.taxonomyPackageDoesNotExist(TaxonomyQueryControllerTest.java:54)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:714)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
at org.testng.TestRunner.privateRun(TestRunner.java:767)
at org.testng.TestRunner.run(TestRunner.java:617)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
at org.testng.SuiteRunner.run(SuiteRunner.java:240)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
at org.testng.TestNG.run(TestNG.java:1057)
at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111)
at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204)
at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:175)

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2020-06-01

共1个答案

一尘不染

注意:对于问题4.1.1.RELEASE中提到的版本,这是正确的。

Spring MVC ResponseEntity通过来处理返回值HttpEntityMethodProcessor

ResponseEntity值未设置主体(如您的代码段中的情况)时,将HttpEntityMethodProcessor尝试根据处理程序方法ResponseEntity签名中的返回类型的参数确定响应主体的内容类型@RequestMapping

因此对于

public ResponseEntity<Void> taxonomyPackageExists( @PathVariable final String key ) {

该类型将是VoidHttpEntityMethodProcessor然后将遍历其所有已注册HttpMessageConverter实例,并找到可以为某种Void类型编写主体的实例。根据您的配置,可能找不到,也可能找不到。

如果确实找到任何内容,则仍然需要确保将使用与请求Accept标头中提供的类型匹配的Content-
Type编写相应的正文application/xml

如果在所有这些检查之后都不HttpMessageConverter存在,Spring MVC将决定它无法产生可接受的响应,因此返回406 Not
Acceptable HTTP响应。

使用ResponseEntity<String>,Spring将String用作响应主体并查找StringHttpMessageConverter作为处理程序。并且由于StringHttpMessageHandler可以产生任何媒体类型的内容(Accept标头中提供),因此它将能够处理application/xml您的客户端所请求的内容。

从那以后,Spring MVC已更改为仅在主体ResponseEntity为NOT的情况下才返回406 null。如果您使用的是Spring
MVC的最新版本,则您不会在原始问题中看到该行为。


iddy85的解决方案中(似乎暗示ResponseEntity<?>了这一点),人体的类型将推断为Object。如果您的类路径中有正确的库,即。杰克逊(版本>
2.5.0)及其XML扩展,Spring
MVC将MappingJackson2XmlHttpMessageConverter可以使用它来application/xml为type
生成Object他们的解决方案仅在这些条件下有效。 否则,由于与我上述相同的原因,它将失败。

2020-06-01