SnakeYaml“找不到属性错误”

Question

下面是我的config.yml的一部分：

#Authenctication
AuthenticationConfig:
  AuthencticationType: LDAP
  LDAPConfig:
     LDAPUrl: ldap://localhost:389
     ConnectionType: simple
     LDAPSecurityConfig:
        RootDN: cn=manager,dc=maxcrc,dc=com
        RootPassword: secret
        UserSearchDN: ou=People,dc=maxcrc,dc=com
        GroupdSearchDB: ou=Groups,dc=maxcrc,dc=com

我有一个用于解析的类：

public class YamlConfiguraiton {
    private AuthenticationConfiguration AuthenticationConfig;

    public void setAuthenticationConfig(AuthenticationConfiguration AuthenticationConfig) {
        this.AuthenticationConfig = AuthenticationConfig;
    }

    public AuthenticationConfiguration getAuthenticationConfig() {
        return this.AuthenticationConfig;
    }
}

但是，当我跑的时候

try(InputStream in = new FileInputStream(new File(ymalPath))) {
            yamlConfig = yaml.loadAs(in, YamlConfiguraiton.class);
        } catch (IOException e) {
            e.printStackTrace();
        }

发生以下错误：

Exception in thread "main" Cannot create property=AuthenticationConfig for JavaBean=com.ibm.entity.matching.common.bootstrap.YamlConfiguraiton@e7860081
 in 'reader', line 2, column 1:
    AuthenticationConfig:
    ^
Unable to find property 'AuthenticationConfig' on class: com.ibm.entity.matching.common.bootstrap.YamlConfiguraiton
 in 'reader', line 3, column 4:
       AuthencticationType: LDAP
       ^

    at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:270)
    at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.construct(Constructor.java:149)
    at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.construct(Constructor.java:309)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructObjectNoCheck(BaseConstructor.java:204)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:193)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:159)
    at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:146)
    at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:524)
    at org.yaml.snakeyaml.Yaml.loadAs(Yaml.java:518)
    at com.ibm.entity.matching.bootstrap.EntityMatching.boot(EntityMatching.java:55)
    at com.ibm.entity.matching.bootstrap.EntityMatching.main(EntityMatching.java:35)
Caused by: org.yaml.snakeyaml.error.YAMLException: Unable to find property 'AuthenticationConfig' on class: com.ibm.entity.matching.common.bootstrap.YamlConfiguraiton
    at org.yaml.snakeyaml.introspector.PropertyUtils.getProperty(PropertyUtils.java:159)
    at org.yaml.snakeyaml.introspector.PropertyUtils.getProperty(PropertyUtils.java:148)
    at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.getProperty(Constructor.java:287)
    at org.yaml.snakeyaml.constructor.Constructor$ConstructMapping.constructJavaBean2ndStep(Constructor.java:208)
    ... 10 more

为什么它抱怨不能找到属性AuthenticationConfig，而AuthenticationConfig只是实例变量的名称？

在我将实例变量从“私有”更改为“公共”后，更新了，它们被SnakeYaml识别，但这不是我们所期望的。这些类不能被识别为JavaBean。

更新我找到了根本原因。这是命名惯例。如果希望SnakeYaml解析yaml文件，则必须遵守camelCase。setter和getter方法的名称也很重要。假设有一个名为ldapConfig的私有实例变量，那么它的getter和setter的名称必须是getLdapConfig和setLdapConfig，甚至getLDAPConfig和setLDAPConfig也不能工作。

Answer 1

导致此错误的主要原因是您需要在POJO类(即YamlConfiguraiton)中定义Yaml文件中的所有属性。

可以使用下面的代码跳过未定义的属性。

Representer representer = new Representer();
            representer.getPropertyUtils().setSkipMissingProperties(true);
            Yaml yaml = new Yaml(new Constructor(YamlConfiguraiton.class), representer);

首先，在Yaml文件中将属性名重命名为camelCase。

请参阅以下代码：-

代码：-

public class YamlReadCustom {

    private static String yamlPath = "/authentication.yaml";

    public static void main(String[] args) {
        Representer representer = new Representer();
        representer.getPropertyUtils().setSkipMissingProperties(true);
        Yaml yaml = new Yaml(new Constructor(Authentication.class), representer);
        try(InputStream in = YamlReadCustom.class.getResourceAsStream (yamlPath)) {
            Authentication authentication = yaml.loadAs(in, Authentication.class);
            System.out.println(authentication.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Authentication:-

public class Authentication {
    private String authenticationConfig;
    private String authencticationType;
    private LdapConfig ldapConfig;

    //getters and setters
}

LdapConfig:-

public class LdapConfig {
    private String ldapUrl;
    private String connectionType;
    private Map<String, Object> ldapSecurityConfig;
    //getters and setters
}

authentication.yaml

authenticationConfig:
authencticationType: LDAP
ldapConfig:
  ldapUrl: ldap://localhost:389
  connectionType: simple
  ldapSecurityConfig:
    rootDn: cn=manager,dc=maxcrc,dc=com
    rootPassword: secret
    userSearchDn: ou=People,dc=maxcrc,dc=com
    groupdSearchDb: ou=Groups,dc=maxcrc,dc=com