Spring Boot:使用 @Value 或 @ConfigurationProperties 从 yaml 读取列表 [英] Spring Boot: read list from yaml using @Value or @ConfigurationProperties

问题描述

我想从 yaml 文件 (application.yml) 中读取主机列表，该文件如下所示:

I want to read a list of hosts from a yaml file (application.yml), the file looks like this:

cors:
    hosts:
        allow: 
            - http://foo1/
            - http://foo2/
            - http://foo3/

(示例 1)

我使用的类定义了这样的值:

My class used defines the value like this:

@Value("${cors.hosts.allow}")   
List<String> allowedHosts;

但由于 Spring 抱怨，读取失败:

But reading fails as Spring complains about this:

java.lang.IllegalArgumentException:无法解析占位符字符串值${cors.hosts.allow}"中的cors.hosts.allow"

java.lang.IllegalArgumentException: Could not resolve placeholder 'cors.hosts.allow' in string value "${cors.hosts.allow}"

当我像这样更改文件时，可以读取属性，但它自然不包含列表，而只有一个条目:

When I change the file like this the property can be read but naturally it does not contain the list but only one entry:

cors:
    hosts:
        allow: http://foo1, http://foo2, http://foo3

(我知道我可以将这些值作为单行读取并按 "," 拆分它们，但我还不想寻求解决方法)

(I know that I could read the values as a single line and split them by "," but I do not want to go for a workaround yet)

这也不起作用(尽管我认为根据 snakeyamls docs):

This does not work either (although I think this should be valid according to snakeyamls docs):

cors:
    hosts:
        allow: !!seq [ "http://foo1", "http://foo2" ] 

(跳过 !!seq 而只使用 [/] 也是失败的)

(Skipping the !!seq and just using the [ / ] is a failure too)

我阅读了这里的建议，其中涉及使用 @ConfigurationProperties 并将示例传输到 Java 并与您在示例 1 中看到的 yaml 文件一起使用:

I read the suggestion here which involves using @ConfigurationProperties and transferred the example to Java and used it with the yaml file you see in Example1:

@Configuration
@EnableWebMvc
@ConfigurationProperties(prefix = "cors.hosts")
public class CorsConfiguration extends WebMvcConfigurerAdapter {
    @NotNull
    public List<String> allow;
...

当我运行它时，我收到了这样的投诉:

When I run this I get this complaint:

org.springframework.validation.BindException:org.springframework.boot.bind.RelaxedDataBinder$RelaxedBeanPropertyBindingResult:1 错误字段允许"上的对象cors.hosts"中的字段错误:被拒绝值[空]；代码 [NotNull.cors.hosts.allow,NotNull.allow,NotNull];论据[org.springframework.context.support.DefaultMessageSourceResolvable:代码 [cors.hosts.allow,allow]；参数 ts [];默认消息[允许]];

org.springframework.validation.BindException: org.springframework.boot.bind.RelaxedDataBinder$RelaxedBeanPropertyBindingResult: 1 errors Field error in object 'cors.hosts' on field 'allow': rejected value [null]; codes [NotNull.cors.hosts.allow,NotNull.allow,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [cors.hosts.allow,allow]; argumen ts []; default message [allow]];

我搜索了其他方式让我的 CORS 主机可配置，并找到了这个 Spring Boot问题，但由于尚未完成，我无法将其用作解决方案.所有这些都是通过 Spring Boot 1.3 RC1 完成的

I searched for other means to have my CORS hosts configurable and found this Spring Boot issue but as this is not yet finished I can't use it as a solution. All of this is done with Spring Boot 1.3 RC1

推荐答案

在application.yml中使用逗号分隔值

use comma separated values in application.yml

corsHostsAllow: http://foo1/, http://foo2/, http://foo3/

用于访问的java代码

java code for access

@Value("${corsHostsAllow}")    
String[] corsHostsAllow

我试过了，成功了；)

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