spring属性配置PropertySource、@Value、Environment、@ConfigurationProperties的用法

绝地灬酷狼 2021-10-13 15:54 630阅读 0赞

# 1、@PropertySource注解根据不同环境动态加载自定义配置文件 #

## 1.1、自定义配置文件common-as-dev.properties ##

stu.name=zhangsan
    stu.age=18
    stu.sex=man

## 1.2、pom里配置环境 ##

## 1.3、application.properties里引用环境 ##

spring.profiles.active=@env@
    server.port=@port@
    server.servlet.context-path=@ctx@

## 1.4、@PropertySource加载 ##

@PropertySource("classpath:/common-${spring.profiles.active}.properties")
    @Configuration
    public class LoadProperties {
    
    }

## 1.5、@Value注解引用 ##

@Value("${stu.name}")
    	private String stuName;

# 2、@value和Environment #

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Scope;
    import org.springframework.core.env.Environment;
    import org.springframework.core.env.MapPropertySource;
    import org.springframework.core.env.MutablePropertySources;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.context.support.StandardServletEnvironment;
    
    import java.util.HashMap;
    import java.util.Map;
    
    
    @RestController
    /**
     * @RefreshScope
     * 要引入springcloud的config-server组件
     * 可以自定义注解，来实现等同于refreshScope注解等同的功能
     * @value注解动态刷新的关键是：@Scope注解的proxyMode属性，值默认为ScopedProxyMode.default
     * 当@Scope中proxyMode为TARGET_CLASS的时候，会给当前创建的bean通过cglib生成一个代理对象，通过这个代理对象来访问目标bean对象
     * 当配置修改的时候，调用这些bean的任意方法的时候，就会重新创建一个代理对象
     */
    @Scope
    public class EnvTestController {
    
        /**
         * 可以将配置信息放在db或者其他存储介质中，容器启动的时候，可以将这些信息加载到Environment中，
         * @Value注解 中应用的值最终是通过Environment来解析的，所以只需要扩展一下Environment就可以实现
         */
        @Autowired
        private Environment env;
    
        @Value("${host:0.0.0.0}")
        private String host;
        @Value("${port:0}")
        private Integer port;
    
        {
            //在实例代码块里获取到的env变量一定是null,因为此时bean还没有初始化完成，无法注入env
            if(null == env){
                System.out.println("env为null");
            }
        }
    
        /**
         * 通过代码设置自定义的PropertySource,通过这种方式，@value不能刷新，而env则是能实时获取到值的
         */
        @RequestMapping("/customPropertySource/set")
        public void setCustomPropertySource(){
            StandardServletEnvironment ssEnv = null;
            if(env instanceof StandardServletEnvironment){
                ssEnv = (StandardServletEnvironment)env;
            }
            MutablePropertySources mutablePropertySources = ssEnv.getPropertySources();
            Map<String, Object> map = new HashMap<>();
            map.put("host","192.168.32.1");
            map.put("port",8888);
            MapPropertySource mapPropertySource = new MapPropertySource("my_ps",map);
            mutablePropertySources.addLast(mapPropertySource);
        }
    
        @RequestMapping("/getProp/1/{key}")
        public String getProp1(@PathVariable String key){
            return env.getProperty(key);
        }
    
        @RequestMapping("/getProp/2/{key}")
        public String getProp2(@PathVariable String key){
            if("host".equals(key)){
                return host;
            }else if("port".equals(key)){
                return String.valueOf(port);
            }else{
                return null;
            }
        }
    
    }

# 3、@ConfigurationProperties #

## 3.1、用在类上 ##

import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.PropertySource;
    import org.springframework.stereotype.Component;
    
    @Component
    @PropertySource(value={"classpath:user.properties"},encoding="utf-8")
    @ConfigurationProperties(prefix = "my.user")
    public class UserBean {
       private String name;
       private String age;
       private String email;
    
       public String getName() {
          return name;
       }
    
       public void setName(String name) {
          this.name = name;
       }
    
       public String getAge() {
          return age;
       }
    
       public void setAge(String age) {
          this.age = age;
       }
    
       public String getEmail() {
          return email;
       }
    
       public void setEmail(String email) {
          this.email = email;
       }
    }

## 3.2、用在方法上 ##

import com.asiainfo.com.springboottest.entity.User;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.PropertySource;
    
    @Configuration
    @PropertySource(value={"classpath:user.properties"},encoding="utf-8")
    public class UserBeanConfig {
    
        @Bean
        @ConfigurationProperties(prefix = "my.user")
        public User getUser(){
            return new User();
        }
    
    }