spring boot 注入bean Spring boot将配置属性注入到bean类中
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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 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")
@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}
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