在SpringBoot中使用@Value注解来设置默认值的方法

@Value("${app.port:8080}")
private int port;
@Value("${app.name:MyApp}")
private String appName;

@Value("${app.names:John,Doe}")
private String[] appNames;
@Value("${app.tags:tag1,tag2,tag3}")
private List<String> appTags;

@Value("#{${app.properties:{key1:'value1', key2:'value2'}}}")
private Map<String, String> appProperties;

@Component
public class MyComponent {
    @Value("${app.port:8080}")
    private int port;
    @Value("${app.name:MyApp}")
    private String appName;
    @Value("${app.names:John,Doe}")
    private String[] appNames;
    @Value("${app.tags:tag1,tag2,tag3}")
    private List<String> appTags;
    @Value("#{${app.properties:{key1:'value1', key2:'value2'}}}")
    private Map<String, String> appProperties;
    public void displayValues() {
        System.out.println("Port: " + port);
        System.out.println("App Name: " + appName);
        System.out.println("App Names: " + Arrays.toString(appNames));
        System.out.println("App Tags: " + appTags);
        System.out.println("App Properties: " + appProperties);
    }
}

import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.env.Environment;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Component;
@Component
public class MyComponent {
    @Value("${my.property}")
    private String myProperty;
    @Value("${my.array}")
    private String[] myArray;
    @Value("${my.list}")
    private List<String> myList;
    @Value("${my.environment.property}")
    private String environmentProperty;
    @Value("classpath:path/to/myfile.txt")
    private Resource resource;
    // getter and setter methods
    public void printValues() {
        System.out.println("myProperty: " + myProperty);
        System.out.println("myArray: " + Arrays.toString(myArray));
        System.out.println("myList: " + myList);
        System.out.println("environmentProperty: " + environmentProperty);
        System.out.println("resource: " + resource);
    }
}

my.property=Hello World
my.array=value1,value2,value3
my.list=value1,value2,value3
my.environment.property=my.environment.value

my:
  property: Hello World
  array: value1,value2,value3
  list: value1,value2,value3
  environment:
    property: my.environment.value