@ConfigurationProperties可以用来将值从.properties(.yml也支持)映射到POJO。

考虑下面的示例文件。

. properties

cust.data.employee.name=Sachin
cust.data.employee.dept=Cricket

Employee.java

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@ConfigurationProperties(prefix = "cust.data.employee")
@Configuration("employeeProperties")
public class Employee {

    private String name;
    private String dept;

    //Getters and Setters go here
}

现在可以通过如下方式自动装配employeeProperties来访问属性值。

@Autowired
private Employee employeeProperties;

public void method() {

   String employeeName = employeeProperties.getName();
   String employeeDept = employeeProperties.getDept();

}

遵循以下步骤。 1:-创建你的配置类如下所示

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.beans.factory.annotation.Value;

@Configuration
public class YourConfiguration{

    // passing the key which you set in application.properties
    @Value("${userBucket.path}")
    private String userBucket;

   // getting the value from that key which you set in application.properties
    @Bean
    public String getUserBucketPath() {
        return userBucket;
    }
}

2:-当你有一个配置类时，然后从你需要的配置中注入变量。

@Component
public class YourService {

    @Autowired
    private String getUserBucketPath;

    // now you have a value in getUserBucketPath varibale automatically.
}

另一种在配置中找到键/值的方法。

...
import org.springframework.core.env.ConfigurableEnvironment;
...
@SpringBootApplication
public class MyApplication {

    @Autowired
    private ConfigurableEnvironment  myEnv;

...
  
    @EventListener(ApplicationReadyEvent.class)
    public void doSomethingAfterStartup() 
    throws Exception {
        
        LOG.info("myEnv (userBucket.path): " + myEnv.getProperty("userBucket.path"));
    }
} 

应用程序。Yml或application.properties

config.value1: 10
config.value2: 20
config.str: This is a simle str

MyConfig类

@Configuration
@ConfigurationProperties(prefix = "config")
public class MyConfig {
    int value1;
    int value2;
    String str;

    public int getValue1() {
        return value1;
    }

    // Add the rest of getters here...      
    // Values are already mapped in this class. You can access them via getters.
}

任何想要访问配置值的类

@Import(MyConfig.class)
class MyClass {
    private MyConfig myConfig;

    @Autowired
    public MyClass(MyConfig myConfig) {
        this.myConfig = myConfig;
        System.out.println( myConfig.getValue1() );
    }
}

另一种方法是将org.springframework.core. environment注入到bean中。

@Autowired
private Environment env;
....

public void method() {
    .....  
    String path = env.getProperty("userBucket.path");
    .....
}

可以使用@Value注释从应用程序中读取值。属性/ yml文件。

@Value("${application.name}")
private String applicationName;