属性源没有自动装配

Question

由于某种原因，我正在使用外部属性源，其中一个外部属性源没有自动装配，在创建身份验证 bean 时接收到空指针

错误信息

原因：org.springframework.beans.BeanInstantiationException：无法实例化[com.filechecker.check.Authenticator]：构造函数抛出异常；嵌套异常是 java.lang.NullPointerException

原因：java.lang.NullPointerException: null 在 com.filechecker.check.Authenticator.(Authenticator.java:30) ~[classes!/:0.0.1-SNAPSHOT]

第 30 行：

    String username = emailPropertyConfig.getEmailConfig().getUsername();

不工作一个

@Component
@PropertySource(value="${email.app.properties}",ignoreResourceNotFound = false)
@ConfigurationProperties
public class PropertyEmailConfiguration {

    private EmailConfig emailConfig =  new EmailConfig();

    public EmailConfig getEmailConfig() {
        return emailConfig;
    }

    public void setEmailConfig(EmailConfig emailConfig) {
        this.emailConfig = emailConfig;
    }
}


@Component
public class Authenticator extends javax.mail.Authenticator {

    @Autowired
    PropertyEmailConfiguration emailPropertyConfig;

    @Autowired
    CipherCrypt cipherCrypt;

    private PasswordAuthentication authentication;

    public Authenticator() throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeySpecException {

        String username = emailPropertyConfig.getEmailConfig().getUsername();
        String password = cipherCrypt.decrypt(emailPropertyConfig.getEmailConfig().getEncryptPassword());
        authentication = new PasswordAuthentication(username, password);
    }

    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        return authentication;
    }
}

工作一个

@Component
@PropertySource(value="${external.app.properties}", ignoreResourceNotFound = true)
@ConfigurationProperties
public class PropertyConfiguration {

    private List<FileStructureConfig> fileStructureConfig = new ArrayList();

    private List<EmailSendingProperties> emailSendingProperties  = new ArrayList();

    public List<FileStructureConfig> getFileStructureConfig() {
        return fileStructureConfig;
    }

    public void setFileStructureConfig(List<FileStructureConfig> fileStructureConfig) {
        this.fileStructureConfig = fileStructureConfig;
    }

    public List<EmailSendingProperties> getEmailSendingProperties() {
        return emailSendingProperties;
    }

    public void setEmailSendingProperties(List<EmailSendingProperties> emailSendingProperties) {
        this.emailSendingProperties = emailSendingProperties;
    }


}

Answer 1

您正在尝试访问构造函数中的@Autowired 属性。在此阶段无法自动装配该属性。 为了让 Spring “烘焙 bean”，Spring 必须创建您的对象（使用您的构造函数），然后才应用自动装配机制注入 emailPropertyConfig 和 cipherCrypt。因此，您无法访问构造函数中的两个 @Autowired 属性。

如果您需要从emailPropertyConfig 或cipherCrypt 中提取一些值，您可以在@PostConstruct 中进行操作

@Component
public class Authenticator {

    @Autowired
    PropertyEmailConfiguration emailPropertyConfig;

    @Autowired
    CipherCrypt cipherCrypt;

    private PasswordAuthentication authentication;

    @PostConstruct
    void init() throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeySpecException {

      String username = emailPropertyConfig.getEmailConfig().getUsername();
      String password = cipherCrypt.decrypt(emailPropertyConfig.getEmailConfig().getEncryptPassword());
      authentication = new PasswordAuthentication(username, password);
    }

    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
      return authentication;
    }
}

或使用构造函数注入：

@Component
public class Authenticator {

    PropertyEmailConfiguration emailPropertyConfig;

    CipherCrypt cipherCrypt;

    private PasswordAuthentication authentication;

    public Authenticator(PropertyEmailConfiguration emailPropertyConfig, CipherCrypt cipherCrypt) throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeySpecException {

      String username = emailPropertyConfig.getEmailConfig().getUsername();
      String password = cipherCrypt.decrypt(emailPropertyConfig.getEmailConfig().getEncryptPassword());
      authentication = new PasswordAuthentication(username, password);
    }

    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
      return authentication;
    }
}