Spring boot将配置属性注入到bean类中

一、@ConfigurationProperties注解的使用

看配置文件，我的是yaml格式的配置：

// file application.ymlmy:  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 List<String> servers = new ArrayList<String>();    public List<String> 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")@RestControllerpublic 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.javaimport 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.javaimport 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")@RestControllerpublic 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}

ok，fucking nice