为Jackson序列化/反序列化YAML文档定义带前缀的POJO前缀根节点

Question

我找到了https://github.com/FasterXML/jackson-dataformat-yaml反序列化/序列化YAML文件。然而，我很难反序列化以下内容：

• 我想为要解析为POJO的实际文档定义一个前缀。类似于文档的子树

spring:
  cloud:
    config:
      server:
        git:
          repos:
            publisher:
              uri: 'https://github.company.com/toos/spring-cloud-config-publisher-config'
              cloneOnStart: true
              username: myuser
              password: password
              pullOnRequest: false
              differentProperty: My Value
            config_test_server_config: 
              uri: 'https://github.company.com/mdesales/config-test-server-config'
              cloneOnStart: true
              username: 226b4bb85aa131cd6393acee9c484ec426111d16
              password: ""
              completelyDifferentProp: this is a different one

对于本文档，要求如下：*我想将前缀定义为“spring.cloud.config.server.git”。*我想创建一个表示对象的POJO。

我创建了以下POJO来表示这一点。

• ConfigServerProperties：表示包含repos列表的顶部pojo。
• ConfigServerOnboard：表示文档的每个元素。
  • 每个属性都存储在地图中，以便我们可以添加尽可能多的不同属性。

  每个类如下：

  public class ConfigServerProperties {
  
    private Map<String, ConfigServerOnboard> repos;
  
    public void setRepos(Map<String, ConfigServerOnboard> repos) {
      this.repos = repos;
    }
  
    public Map<String, ConfigServerOnboard> getRepos() {
      return this.repos;
    }
  }
  

  第二类如下：

  public class ConfigServerOnboard {
  
    private Map<String, String> properties;
  
    public Map<String, String> getProperties() {
      return properties;
    }
  
    public void setProperties(Map<String, String> properties) {
      this.properties = properties;
    }
  
  }
  

  我尝试的反序列化策略如下：

    public static ConfigServerProperties parseProperties(File filePath)
        throws JsonParseException, JsonMappingException, IOException {
  
      ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
      JsonNodeFactory jsonNodeFactory = new JsonNodeFactory(false);
      jsonNodeFactory.textNode("spring.cloud.config");
      // tried to use this attempting to get the prefix
      mapper.setNodeFactory(jsonNodeFactory);
      ConfigServerProperties user = mapper.readValue(filePath, ConfigServerProperties.class);
      return user;
    }
  

  Exception in thread "main" com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "spring" (class com.company.platform.config.onboarding.files.config.model.ConfigServerProperties), not marked as ignorable (one known property: "repos"])
   at [Source: /tmp/config-server-onboards.yml; line: 3, column: 3] (through reference chain: com.company.platform.config.onboarding.files.config.model.ConfigServerProperties["spring"])
      at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:62)
      at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:834)
      at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1094)
      at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1470)
      at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1448)
      at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:282)
      at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140)
      at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3798)
      at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2740)
      at com.company.platform.config.onboarding.files.config.model.ConfigServerProperties.parseProperties(ConfigServerProperties.java:37)
      at com.company.platform.config.onboarding.files.config.model.ConfigServerProperties.main(ConfigServerProperties.java:42)
  

  我对使用SpringBoot的ConfigurationProperties（"spring.cloud.config.server.git"）的解决方案持开放态度。这样，我们可以有以下内容：

  @ConfigurationProperties("spring.cloud.config.server.git")
  public class Configuration {
  
    private Map<String, Map<String, String>> repos = new LinkedHashMap<String, new HashMap<String, String>>();
  
    // getter/setter
  }
  

  • 如何设置文档的根元素
  • 反序列化必须读取文档并生成POJO实例
  • 序列化必须生成具有更新值的同一文档

Answer 1

我必须想到以下几点：

>

创建6个类，每个类都有前缀“spring.cloud.config.server.git”所需的属性

• SpringCloudConfigSpring。爪哇语

所有这些文件的持有者都是SpringCloudConfigFile。Java语言

持有者和所有类都有一个对下一个属性的引用，下一个属性有一个对下一个的引用，等等，像往常一样使用他们自己的setter/getter方法。

public class SpringCloudConfigSpring {

  private SpringCloudConfigCloud cloud;

  public SpringCloudConfigCloud getCloud() {
    return cloud;
  }

  public void setCloud(SpringCloudConfigCloud cloud) {
    this.cloud = cloud;
  }
}

• 轻松实现了地图的表示。

最后一个我使用TreeMap的引用来保持键的排序，另一个映射来表示可以添加的任何属性，而不更改表示。

public class SpringCloudConfigGit {

  TreeMap<String, Map<String, Object>> repos;

  public TreeMap<String, Map<String, Object>> getRepos() {
    return repos;
  }

  public void setRepos(TreeMap<String, Map<String, Object>> repos) {
    this.repos = repos;
  }

}

按如下方式创建验证：

  public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException {
    File config = new File("/tmp/config-server-onboards.yml");
    SpringCloudConfigFile props = ConfigServerProperties.parseProperties(config);
    props.getSpring().getCloud().getConfig().getServer().getGit().getRepos().forEach((appName, properties) -> {
      System.out.println("################## " + appName + " #######################3");
      System.out.println(properties);
      if (appName.equals("github_pages_reference")) {
        properties.put("name", "Marcello");
        properties.put("cloneOnStart", true);
      }
      System.out.println("");
    });

    saveProperties(new File(config.getAbsoluteFile().getParentFile(), "updated-config-onboards.yml"), props);
  }

输出如下：

################## config_onboarding #######################3
{uri=https://github.company.com/servicesplatform-tools/spring-cloud-config-onboarding-config, cloneOnStart=true, username=226b4bb85aa131cd6393acee9c484ec426111d16, password=, pullOnRequest=false}

################## config_test_server_config #######################3
{uri=https://github.company.com/rlynch2/config-test-server-config, cloneOnStart=true, username=226b4bb85aa131cd6393acee9c484ec426111d16, password=, pullOnRequest=false}

################## github_pages_reference #######################3
{uri=https://github.company.com/servicesplatform-tools/spring-cloud-config-reference-service-config, cloneOnStart=true, username=226b4bb85aa131cd6393acee9c484ec426111d16, password=, pullOnRequest=false}

需要进行明显的改进：

• 我希望有一个单一类的解决方案

  public static SpringCloudConfigFile parseProperties(File filePath)
      throws JsonParseException, JsonMappingException, IOException {

    ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
    SpringCloudConfigFile file = mapper.readValue(filePath, SpringCloudConfigFile.class);
    return file;
  }

  public static void saveProperties(File filePath, SpringCloudConfigFile file) throws JsonGenerationException, JsonMappingException, IOException {
    ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
    mapper.writeValue(filePath, file);
  }

• 它保持了已实现的排序键。