Springboot如何实现将属性注入到bean类
今天就跟大家聊聊有关Springboot如何实现将属性注入到bean类,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
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一、@ConfigurationProperties注解的使用
看配置文件,我的是yaml格式的配置:
// file application.yml my: servers: - dev.bar.com - foo.bar.com - jiaobuchong.com
下面我要将上面的配置属性注入到一个Java Bean类中,看码:
import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.stereotype.Component; import java.util.ArrayList; import java.util.List; /** * file: MyConfig.java * Created by jiaobuchong on 12/29/15. */ @Component //不加这个注解的话, 使用@Autowired 就不能注入进去了 @ConfigurationProperties(prefix = "my") // 配置文件中的前缀 public class MyConfig { private Listservers = new ArrayList (); public List getServers() { return this.servers; } }
下面写一个Controller来测试一下:
/** * file: HelloController * Created by jiaobuchong on 2015/12/4. */ @RequestMapping("/test") @RestController public class HelloController { @Autowired private MyConfig myConfig; @RequestMapping("/config") public Object getConfig() { return myConfig.getServers(); } }
下面运行Application.java的main方法跑一下看看:
@Configuration //标注一个类是配置类,spring boot在扫到这个注解时自动加载这个类相关的功能,比如前面的文章中介绍的配置AOP和拦截器时加在类上的Configuration @EnableAutoConfiguration //启用自动配置 该框架就能够进行行为的配置,以引导应用程序的启动与运行, 根据导入的starter-pom 自动加载配置 @ComponentScan //扫描组件 @ComponentScan(value = "com.spriboot.controller") 配置扫描组件的路径 public class Application { public static void main(String[] args) { // 启动Spring Boot项目的唯一入口 SpringApplication app = new SpringApplication(Application.class); app.setBannerMode(Banner.Mode.OFF); app.run(args); }
在浏览器的地址栏里输入:
localhost:8080/test/config 得到:
[“dev.bar.com”,”foo.bar.com”,”jiaobuchong.com”]
二、@ConfigurationProperties和@EnableConfigurationProperties注解结合使用
在spring boot中使用yaml进行配置的一般步骤是,
1、yaml配置文件,这里假设:
my: webserver: #HTTP 监听端口 port: 80 #嵌入Web服务器的线程池配置 threadPool: maxThreads: 100 minThreads: 8 idleTimeout: 60000
2、
//file MyWebServerConfigurationProperties.java import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties(prefix = "my.webserver") public class MyWebServerConfigurationProperties { private int port; private ThreadPool threadPool; public int getPort() { return port; } public void setPort(int port) { this.port = port; } public ThreadPool getThreadPool() { return threadPool; } public void setThreadPool(ThreadPool threadPool) { this.threadPool = threadPool; } public static class ThreadPool { private int maxThreads; private int minThreads; private int idleTimeout; public int getIdleTimeout() { return idleTimeout; } public void setIdleTimeout(int idleTimeout) { this.idleTimeout = idleTimeout; } public int getMaxThreads() { return maxThreads; } public void setMaxThreads(int maxThreads) { this.maxThreads = maxThreads; } public int getMinThreads() { return minThreads; } public void setMinThreads(int minThreads) { this.minThreads = minThreads; } } }
3、
// file: MyWebServerConfiguration.java import org.springframework.context.annotation.Configuration; import org.springframework.boot.context.properties.EnableConfigurationProperties; @Configuration @EnableConfigurationProperties(MyWebServerConfigurationProperties.class) public class MyWebServerConfiguration { @Autowired private MyWebServerConfigurationProperties properties; /** *下面就可以引用MyWebServerConfigurationProperties类 里的配置了 */ public void setMyconfig() { String port = properties.getPort(); // ........... } }
The @EnableConfigurationProperties annotation is automatically applied to your project so that any beans annotated with @ConfigurationProperties will be configured from the Environment properties. This style of configuration works particularly well with the SpringApplication external YAML configuration.(引自spring boot官方手册)
三、@Bean配置第三方组件(Third-party configuration)
创建一个bean类:
// file ThreadPoolBean.java /** * Created by jiaobuchong on 1/4/16. */ public class ThreadPoolBean { private int maxThreads; private int minThreads; private int idleTimeout; public int getMaxThreads() { return maxThreads; } public void setMaxThreads(int maxThreads) { this.maxThreads = maxThreads; } public int getMinThreads() { return minThreads; } public void setMinThreads(int minThreads) { this.minThreads = minThreads; } public int getIdleTimeout() { return idleTimeout; } public void setIdleTimeout(int idleTimeout) { this.idleTimeout = idleTimeout; } }
引用前面第二部分写的配置类:MyWebServerConfiguration.java和MyWebServerConfigurationProperties.java以及yaml配置文件,现在修改MyWebServerConfiguration.java类:
import com.jiaobuchong.springboot.domain.ThreadPoolBean; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; /** * Created by jiaobuchong on 1/4/16. */ @Configuration //这是一个配置类,与@Service、@Component的效果类似。spring会扫描到这个类,@Bean才会生效,将ThreadPoolBean这个返回值类注册到spring上下文环境中 @EnableConfigurationProperties(MyWebServerConfigurationProperties.class) //通过这个注解, 将MyWebServerConfigurationProperties这个类的配置到上下文环境中,本类中使用的@Autowired注解注入才能生效 public class MyWebServerConfiguration { @SuppressWarnings("SpringJavaAutowiringInspection") //加这个注解让IDE 不报: Could not autowire @Autowired private MyWebServerConfigurationProperties properties; @Bean //@Bean注解在方法上,返回值是一个类的实例,并声明这个返回值(返回一个对象)是spring上下文环境中的一个bean public ThreadPoolBean getThreadBean() { MyWebServerConfigurationProperties.ThreadPool threadPool = properties.getThreadPool(); ThreadPoolBean threadPoolBean = new ThreadPoolBean(); threadPoolBean.setIdleTimeout(threadPool.getIdleTimeout()); threadPoolBean.setMaxThreads(threadPool.getMaxThreads()); threadPoolBean.setMinThreads(threadPool.getMinThreads()); return threadPoolBean; } }
被@Configuration注解标识的类,通常作为一个配置类,这就类似于一个xml文件,表示在该类中将配置Bean元数据,其作用类似于Spring里面application-context.xml的配置文件,而@Bean标签,则类似于该xml文件中,声明的一个bean实例。
写一个controller测试一下:
import com.jiaobuchong.springboot.domain.ThreadPoolBean; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; /** * Created by jiaobuchong on 2015/12/4. */ @RequestMapping("/first") @RestController public class HelloController { @Autowired private ThreadPoolBean threadPoolBean; @RequestMapping("/testbean") public Object getThreadBean() { return threadPoolBean; } }
运行Application.java的main方法,
在浏览器里输入:http://localhost:8080/first/testbean
得到的返回值是:
{“maxThreads”:100,”minThreads”:8,”idleTimeout”:60000}
看完上述内容,你们对Springboot如何实现将属性注入到bean类有进一步的了解吗?如果还想了解更多知识或者相关内容,请关注创新互联行业资讯频道,感谢大家的支持。
本文标题:Springboot如何实现将属性注入到bean类
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