通过自定义配置源可以接入自己的配置服务，配合ContextRefresher可以让应用运行中自动更新配置。
实现PropertySourceLocator
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public class MyPropertySourceLocator implements PropertySourceLocator {
@Override
public PropertySource<?> locate(Environment environment) {
String msg = new SimpleDateFormat("HH:mm:ss").format(new Date());
Map<String, Object> map = new HashMap<>();
map.put("demo.diy.msg", msg);
System.err.println("MyPropertySourceLocator, demo.diy.msg = " + msg);
MapPropertySource source = new MapPropertySource("my-source", map);
return source;
}
}
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配置类
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| @Configuration
public class MyConfigBootstrapConfiguration {
@Bean
public MyPropertySourceLocator myPropertySourceLocator() {
return new MyPropertySourceLocator();
}
}
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用Java代码声明bean，还需要在resources/META-INF/spring.factories中声明
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| org.springframework.cloud.bootstrap.BootstrapConfiguration=\
com.netease.ag.demoweb.MyConfigBootstrapConfiguration
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Spring中类似与Java SPI的加载机制。它在META-INF/spring.factories文件中配置接口的实现类名称，然后在程序中读取这些配置文件并实例化。这种自定义的SPI机制是Spring Boot Starter实现的基础。
使用自定义配置
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| @RefreshScope
@Component
@Data
public class ValueConfig {
@Value("${demo.copy.msg}")
private String copyMsg;
@Value("${demo.diy.msg}")
private String diyMsg;
public ValueConfig() {
System.err.println("ValueConfig init");
}
}
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application.properties中可以引用自定义配置
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| demo.copy.msg=${demo.diy.msg}
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springboot应用启动
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| @SpringBootApplication
@RestController
public class DemowebApplication {
@Resource
private ValueConfig valueConfig;
@Resource
private ContextRefresher contextRefresher;
public DemowebApplication() {
System.err.println("DemowebApplication init");
}
public static void main(String[] args) {
SpringApplication.run(DemowebApplication.class, args);
}
@RequestMapping("/t")
public String t() {
return valueConfig.toString();
}
@RequestMapping("/r")
public Object r() {
return contextRefresher.refresh();
}
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启动日志
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| . ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.2.RELEASE)
MyPropertySourceLocator, demo.diy.msg = 17:18:22
...
DemowebApplication init
...
ValueConfig init
...Tomcat started on port(s): 8080 (http)
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查询，多次请求返回一致
请求：http://localhost:8080/t
响应：ValueConfig(copyMsg=17:18:22, diyMsg=17:18:22)
更新
请求：http://localhost:8080/r
响应：[“demo.diy.msg”]
日志输出：
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| MyPropertySourceLocator, demo.diy.msg = 17:27:44
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再次调用查询接口，发现值改变，并且输出日志
证明更新字段实际是重新生成了一个bean
