Spring boot将配置属性注入到bean类中

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.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 List servers = 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、http://@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

http:// 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}

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