java - 动态操作应用程序属性 - 保险库设置(或任何其他值)

Question

我希望能够在我的应用程序使用的 3rd 方组件之间灵活选择。 ATM 我有硬编码值

spring.cloud.vault.token=ffffffff-ffff-ffff-ffff-ffffffffffff
spring.cloud.vault.scheme=http
spring.cloud.vault.application-name=test
spring.cloud.vault.host=127.0.0.1
spring.cloud.vault.port=8200

目标是:

如 spring.cloud.vault.host设置尝试使用它。如 spring.cloud.vault.host是空用
本地数据库代替(具有适当的配置)

我的第一个想法是使用 environment变量如:

spring.cloud.vault.token=${VAULT_TOKEN}
spring.cloud.vault.scheme=${VAULT_SCHEME}
spring.cloud.vault.application-name=${VAULT_APP_NAME}
spring.cloud.vault.host=${VAULT_HOST}
spring.cloud.vault.port=${VAULT_PORT}

然后使用组件类，如:

@Component
public class VaultHelper {
    private final VaultOperations vaultOperations;
    @Value("${spring.cloud.vault.host}")
    String vaultHostname;

    @Autowired
    public VaultHelper(VaultOperations vaultOperations){
        this.vaultOperations = vaultOperations;
    }

    public void saveToVault(String password){
        if (!vaultHostname.equals("")) { 
            // Use vaultOperations to store password
        } else {
            // Use plaintext db storage
        }
    }

    public byte[] readFromVault(String passwordLoc){
        if (!vaultHostname.equals("")) {
            // Use vaultOperations to access password
        } else {
            // return plaintext password
        }
        return new byte[0];
    }


}

这样我就可以设置 ${VAULT_HOST}都来自环境变量(从 docker-compose 运行应用程序)或只是设置 --spring.cloud.vault.host=URL在本地机器上为 java范围。

不幸的是，我在解析时遇到异常 ${VAULT_PORT} field

Caused by: org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [int] for value '${VAULT_PORT}'; nested exception is java.lang.NumberFormatException: For input string: "${VAULT_PORT}"
    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:47) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:191) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.BindConverter$CompositeConversionService.convert(BindConverter.java:170) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.BindConverter.convert(BindConverter.java:96) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.BindConverter.convert(BindConverter.java:88) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.Binder.bindProperty(Binder.java:435) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.Binder.bindObject(Binder.java:380) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:320) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
    ... 83 common frames omitted
Caused by: java.lang.NumberFormatException: For input string: "${VAULT_PORT}"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_231]
    at java.lang.Integer.parseInt(Integer.java:569) ~[na:1.8.0_231]
    at java.lang.Integer.valueOf(Integer.java:766) ~[na:1.8.0_231]
    at org.springframework.util.NumberUtils.parseNumber(NumberUtils.java:211) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.core.convert.support.StringToNumberConverterFactory$StringToNumber.convert(StringToNumberConverterFactory.java:62) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.core.convert.support.StringToNumberConverterFactory$StringToNumber.convert(StringToNumberConverterFactory.java:49) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.core.convert.support.GenericConversionService$ConverterFactoryAdapter.convert(GenericConversionService.java:436) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:41) ~[spring-core-5.2.1.RELEASE.jar:5.2.1.RELEASE]
    ... 90 common frames omitted


Process finished with exit code 1

谁能给我一个提示如何使它工作？

Answer 1

我想事实上，您没有提供默认/后备。在这种情况下，当它找不到相应的环境变量时，它只是将字段 PORT 声明为给定的字符串。尝试使用 (:) 默认值。

您还可以提供另一个变量作为默认值，您知道它将被设置。

spring.cloud.vault.port=${VAULT_PORT}:9000


spring.cloud.vault.port=${VAULT_PORT:8200}