Spring Boot系列 – 4. 读取配置文件（application.yml）中的属性值

在spring boot中，简单几步，读取配置文件（application.yml）中各种不同类型的属性值：

1、引入依赖：

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

2、配置文件（application.yml）中配置各个属性的值：

myProps: #自定义的属性和值  
  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 

3、创建一个bean来接收配置信息：

@Component  
@ConfigurationProperties(prefix="myProps") //接收application.yml中的myProps下面的属性  
public class MyProps {  
    private String simpleProp;  
    private String[] arrayProps;  
    private List<Map<String, String>> listProp1 = new ArrayList<>(); //接收prop1里面的属性值  
    private List<String> listProp2 = new ArrayList<>(); //接收prop2里面的属性值  
    private Map<String, String> mapProps = new HashMap<>(); //接收prop1里面的属性值  
      
    public String getSimpleProp() {  
        return simpleProp;  
    }  
      
    //String类型的一定需要setter来接收属性值；maps, collections, 和 arrays 不需要  
    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;  
    }  
}

启动后，这个bean里面的属性就会自动接收配置的值了。

4、单元测试用例：

@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()));  
    }  

测试结果：

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"}  

源代码参考：https://github.com/xujijun/my-spring-boot

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