如何使用@ConfigurationProperties进行列表值或数组值映射？

Question

我有一个项目，我想配置字符串键“组” 字符串键“命令”的字符串数组。也就是说，我想 能够表达的东西像config.yml以下，并通过 消费@ConfigurationProperties（PREFIX =“config.base”）：

--- 
config: 
    base: 
    "bin group": 
    - "Directory Listing": ["/bin/ls", "-la"] 
    - "Server Date/Time": ["/bin/date", "-u"] 
    "usr/bin group": 
    - "Find .txt Files": ["/usr/bin/find", ".", "-name", "*.txt"] 
    "usr/local/bin group": 
    - "Tree Listing": ["/usr/local/bin/tree"] 

理想的情况下，我d想@ConfigurationProperties对象是一个LinkedHashMap<String, LinkedHashMap<String, String[]>>

但我不知道如何做到这一点。或者任何合理的接近。 我已经得到最接近的是这样的：

package us.w7tek.bug; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.boot.SpringApplication; 
import org.springframework.boot.autoconfigure.SpringBootApplication; 
import org.springframework.boot.context.properties.ConfigurationProperties; 
import org.springframework.boot.context.properties.EnableConfigurationProperties; 
import org.springframework.context.annotation.Bean; 
import org.springframework.stereotype.Controller; 

import javax.annotation.PostConstruct; 
import java.util.LinkedHashMap; 

@EnableConfigurationProperties 
@SpringBootApplication 
public class MainApplication { 

    public static void main(String[] args) { 
     SpringApplication.run(MainApplication.class, args); 
    } 

    @ConfigurationProperties("someConfig") 
    @Bean 
    public ExternalizedConfig externalizedConfig() { return new ExternalizedConfig(); } 

    public static class ExternalizedConfig extends LinkedHashMap<String, String[]> { 
     // oops, @ConfigurationProperties ends up putting LinkedHashMap<String, String> in the values of the top-level mapping, 
     // and that second-level LinkedHashMap has keys that could have come from Integer#toString 
    } 

    @Controller 
    public static class ControllerThatConsumesConfig { 
     private static final String A_KEY_THAT_COULDNT_BE_A_PROPERTY_NAME = "this == config cannot be expressed as a bean with properties, because the keys cannot be made into Java language identifiers for bean property setters and getters"; 

     @Autowired 
     ExternalizedConfig config; 

     @PostConstruct 
     void init() { 
      String[] strings = config.get(A_KEY_THAT_COULDNT_BE_A_PROPERTY_NAME); // ClassCastException occurs here 

      // doesn't have to occur in @PostConstruct, that was just a convenient place for my demo. 
     } 
    } 
} 

用下面的例子application.yml项目：

--- 
someConfig: 
    "this is a key": ["this", "value", "is", "not", "an", "String[]"] 
    "this is another key": ["it", "is", "deserialized", "as", "LinkedHashMap", "having", "keys", "like", "\"0\"", "and", "\"1\"", "etc."] 
    "this == config cannot be expressed as a bean with properties, because the keys cannot be made into Java language identifiers for bean property setters and getters": ["thereby", "subverting", "Java's", "static", "typing", "and", "resulting", "in", "ClassCastException", "at", "runtime"] 

正如评论指出，该代码爆炸当弹簧引导@ConfigurationProperties粘结剂创建一个LinkedHashMap<String, LinkedHashMap<String, LinkedHashMap<String, String>>>类型的对象，并将其放在config字段中。当然，只要有任何方法根据其静态声明类型访问config，就会发生ClassCastException。我不确定是否相信这是一个使用@ConfigurationProperties所使用的属性联编程序代码的错误，或者只是我的重大误解。我认为上面的代码是展示问题的最简单的事情。也可在https://github.com/w7tek/demo-configproperties-bug.git找到，以防有人想编译并运行以查看堆栈跟踪。

有没有人有收集@ConfigurationProperties的任何例子？通过简单地将声明的类型与Spring已经反序列化的实际类型进行匹配，我可以从中找到前进的方向，但这最终导致使用起来不方便。如果可能的话，我真的很想获得这个配置的最内层的值，如列表<>或数组类型，但我不知道如何。

Answer 1

这里是你需要的东西：

不使用选项卡，使用2个空间，每个内部元件。

config: 
    base: 
    "bin group": 
     "Directory Listing": ["/bin/ls", "-la"] 
     "Server Date/Time": ["/bin/date", "-u"] 
    "usr/bin group": 
     "Find txt Files": ["/usr/bin/find", ".", "-name", "*.txt"] 
    "usr/local/bin group": 
     "Tree Listing": ["/usr/local/bin/tree"] 

，这里是配置类： “”

@Configuration 
@ConfigurationProperties(prefix = "config") 
public class Conf_Test { 

    private LinkedHashMap<String, LinkedHashMap<String, List<String>>> base; 

    public LinkedHashMap<String, LinkedHashMap<String, List<String>>> getBase() { 
    return base; 
    } 

    public void setBase(LinkedHashMap<String, LinkedHashMap<String, List<String>>> base) { 
    this.base = base; 
    } 

} 

Apperantly，你不能使用在地图键里面，它只是剪掉了键，所以我删除了“Find .txt Files”键中的那个键。此外，spring-boot不支持映射内部的自动格式化数组，因此String []现在不可能，但列表正在工作。