Java 使用Spring Data REST时，如何更改Jacksons配置？

我正在尝试配置Jackson以ISO8601格式显示JSR310实例

@Configuration
class Jackson {

    @Bean
    static ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper().findAndRegisterModules();
        objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
        return objectMapper;
    }
}

然而，这不是一个独特的Bean，实际上我只想禁用这个设置。因此，我并不真正想要创建ObjectMapper，而是在其上指定一个设置

java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.actuate.autoconfigure.EndpointWebMvcHypermediaManagementContextConfiguration$MvcEndpointAdvice': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.fasterxml.jackson.databind.ObjectMapper org.springframework.boot.actuate.autoconfigure.EndpointWebMvcHypermediaManagementContextConfiguration$MvcEndpointAdvice.mapper; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.fasterxml.jackson.databind.ObjectMapper] is defined: expected single matching bean but found 3: objectMapper,halObjectMapper,_halObjectMapper
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:834)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:667)
at org.springframework.boot.SpringApplication.doRun(SpringApplication.java:342)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:273)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:980)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:969)
at com.xenoterracide.example.Application.main(Application.java:9)
... 5 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.fasterxml.jackson.databind.ObjectMapper org.springframework.boot.actuate.autoconfigure.EndpointWebMvcHypermediaManagementContextConfiguration$MvcEndpointAdvice.mapper; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.fasterxml.jackson.databind.ObjectMapper] is defined: expected single matching bean but found 3: objectMapper,halObjectMapper,_halObjectMapper
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:571)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
... 22 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.fasterxml.jackson.databind.ObjectMapper] is defined: expected single matching bean but found 3: objectMapper,halObjectMapper,_halObjectMapper
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1079)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:967)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:543)
... 24 more

虽然不是必需的，但下面是我的

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://maven.apache.org/POM/4.0.0"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.xenoterracide</groupId>
  <artifactId>modern-spring-web-development</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <java.version>1.8</java.version>
  </properties>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.0.M5</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jsr310</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-rest</artifactId>
    </dependency>
    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
    </dependency>


  </dependencies>

  <repositories>
    <repository>
      <id>spring-milestones</id>
      <name>Spring Milestones</name>
      <url>http://repo.spring.io/milestone</url>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>
  </repositories>

</project>

---

如何在默认对象映射器上重新配置这一设置？

我认为一种方法可以是将

对象映射器

注入合适的bean类中，然后在

@PostConstruct

方法中进行设置，例如：

@Configuration // or @Service or some bean
public class SomeClass ... {

    @Autowired
    private ObjectMapper objectMapper;

    @PostConstruct
    private void configureObjectMapper() {
        objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
    }

}

---

我认为一种方法是将

ObjectMapper

注入合适的bean类中，然后在

@PostConstruct

方法中进行设置，例如：

@Configuration // or @Service or some bean
public class SomeClass ... {

    @Autowired
    private ObjectMapper objectMapper;

    @PostConstruct
    private void configureObjectMapper() {
        objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
    }

}

---

实际上，只需在application.properties（或application.yml）中使用jackson自动配置属性，就可以使其更易于启动：

---

实际上，只需在application.properties（或application.yml）中使用jackson自动配置属性，就可以使其更易于启动：

---

经过一些实验，我发现如果我用它注释我的“setter”（setter注入），它就会运行。这比使用字段注入和

@PostConstruct

更简单、更干净

@Configuration
class Jackson {

   @Autowired
   void configureObjectMapper( final ObjectMapper objectMapper ) {
    objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
   }
}

---

经过一些实验，我发现如果我用它注释我的“setter”（setter注入），它就会运行。这比使用字段注入和

@PostConstruct

更简单、更干净

@Configuration
class Jackson {

   @Autowired
   void configureObjectMapper( final ObjectMapper objectMapper ) {
    objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
   }
}

您可以（也可能应该）使用

repositoryrestconfiguureradapter

（在Spring Data Rest 2.4中）或

RepositoryRestMvcConfiguration

来公开

configureObjectMapper

方法

@Configuration
class RepositoryRestAdapterConfiguration extends RepositoryRestConfigurerAdapter {

    @Override
    public void configureJacksonObjectMapper(ObjectMapper objectMapper) {
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
    }

}

您可以（也可能应该）使用

repositoryrestconfiguureradapter

（在Spring Data Rest 2.4中）或

RepositoryRestMvcConfiguration

来公开

configureObjectMapper

方法

@Configuration
class RepositoryRestAdapterConfiguration extends RepositoryRestConfigurerAdapter {

    @Override
    public void configureJacksonObjectMapper(ObjectMapper objectMapper) {
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.disable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS );
    }

}

---

所以我尝试了

@Autowired-void-configureObjectMapper（ObjectMapper）{….}

但是它从来没有被调用过，为什么这样做不起作用？不确定为什么没有被调用。所以我尝试了

@Autowired-void-configureObjectMapper（ObjectMapper）{….}

但是它从来没有被调用过，为什么这样做有效，而那样做无效？不确定为什么没有调用。功能不错，但我看不出自己想在不同的环境中更改此配置（不像show sql）。因此，如果不那么简洁的话，用Java配置来配置它似乎更合适。使用属性进行更改似乎也更容易发生意外更改。我认为使用配置功能可以避免样板代码，并将重点放在业务逻辑上，而不是放在低级编码上。另外，您不需要显式地创建ObjectMapperbean，SpringBoot可以为您创建。很明显，我现在不是在创建它，我写了一个后续问题，问我为什么尝试的方法不起作用。诚恳地欢迎您提出这种意见，我喜欢springs

属性

，等等，因为有些东西，而不是您不应该在部署时更改的东西。功能不错，但我看不出自己想要在不同的环境中更改此配置（不像show sql）。因此，如果不那么简洁的话，用Java配置来配置它似乎更合适。使用属性进行更改似乎也更容易发生意外更改。我认为使用配置功能可以避免样板代码，并将重点放在业务逻辑上，而不是放在低级编码上。另外，您不需要显式地创建ObjectMapperbean，SpringBoot可以为您创建。很明显，我现在不是在创建它，我写了一个后续问题，问我为什么尝试的方法不起作用。诚恳地欢迎你这么说，我喜欢弹簧的属性等等，只是不是在部署时不应该更改的内容。请注意，这是我在Spring Boot 1.4+中能够使用的唯一方法，以前使用的方法不起作用。请注意，这是我在Spring Boot 1.4+中能够使用的唯一方法，以前使用的方法不起作用。