Spring Boot系列 – 4. 讀取配置文件（application.yml）中的屬性值

在spring boot中，簡單幾步，讀取配置文件（application.yml）中各類不一樣類型的屬性值：

一、引入依賴：

<!-- 支持 @ConfigurationProperties 註解 -->  
<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-configuration-processor</artifactId>  
    <optional>true</optional>  
</dependency>

二、配置文件（application.yml）中配置各個屬性的值：

myProps: #自定義的屬性和值  
  simpleProp: simplePropValue  
  arrayProps: 1,2,3,4,5  
  listProp1:  
    - name: abc  
      value: abcValue  
    - name: efg  
      value: efgValue  
  listProp2:  
    - config2Value1  
    - config2Vavlue2  
  mapProps:  
    key1: value1  
    key2: value2

三、建立一個bean來接收配置信息：

@Component  
@ConfigurationProperties(prefix="myProps") //接收application.yml中的myProps下面的屬性  
public class MyProps {  
    private String simpleProp;  
    private String[] arrayProps;  
    private List<Map<String, String>> listProp1 = new ArrayList<>(); //接收prop1裏面的屬性值  
    private List<String> listProp2 = new ArrayList<>(); //接收prop2裏面的屬性值  
    private Map<String, String> mapProps = new HashMap<>(); //接收prop1裏面的屬性值  
      
    public String getSimpleProp() {  
        return simpleProp;  
    }  
      
    //String類型的必定須要setter來接收屬性值；maps, collections, 和 arrays 不須要  
    public void setSimpleProp(String simpleProp) {  
        this.simpleProp = simpleProp;  
    }  
      
    public List<Map<String, String>> getListProp1() {  
        return listProp1;  
    }  
    public List<String> getListProp2() {  
        return listProp2;  
    }  
  
    public String[] getArrayProps() {  
        return arrayProps;  
    }  
  
    public void setArrayProps(String[] arrayProps) {  
        this.arrayProps = arrayProps;  
    }  
  
    public Map<String, String> getMapProps() {  
        return mapProps;  
    }  
  
    public void setMapProps(Map<String, String> mapProps) {  
        this.mapProps = mapProps;  
    }  
}

啓動後，這個bean裏面的屬性就會自動接收配置的值了。

四、單元測試用例：

@Autowired  
    private MyProps myProps;   
      
    @Test  
    public void propsTest() throws JsonProcessingException {  
        System.out.println("simpleProp: " + myProps.getSimpleProp());  
        System.out.println("arrayProps: " + objectMapper.writeValueAsString(myProps.getArrayProps()));  
        System.out.println("listProp1: " + objectMapper.writeValueAsString(myProps.getListProp1()));  
        System.out.println("listProp2: " + objectMapper.writeValueAsString(myProps.getListProp2()));  
        System.out.println("mapProps: " + objectMapper.writeValueAsString(myProps.getMapProps()));  
    }

測試結果：

simpleProp: simplePropValue  
arrayProps: ["1","2","3","4","5"]  
listProp1: [{"name":"abc","value":"abcValue"},{"name":"efg","value":"efgValue"}]  
listProp2: ["config2Value1","config2Vavlue2"]  
mapProps: {"key1":"value1","key2":"value2"}

源代碼參考：https://github.com/xujijun/my-spring-boot 歡迎關注 [Java架構師社區][1]公衆號

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