标签：min end 获取 oid logs idle .com cep wait
1.读取环境变量
凡是被spring管理的类，实现接口EnvironmentAware 重写方法 setEnvironment 可以在工程启动时，获取到系统环境变量和application配置文件中的变量。
主要是@Configuration，实现接口：EnvironmentAware就能获取到系统环境信息
package me.shijunjie.config; import org.springframework.beans.factory.annotation.Value; import org.springframework.boot.bind.RelaxedPropertyResolver; import org.springframework.context.EnvironmentAware; import org.springframework.context.annotation.Configuration; import org.springframework.core.env.Environment; @Configuration public class MyEnvironmentAware implements EnvironmentAware { @Value("${spring.datasource.url}") private String url; @Override public void setEnvironment(Environment env) { //打印注入的属性信息. System.out.println(url); //通过 environment 获取到系统属性. System.out.println(env.getProperty("JAVA_HOME")); //通过 environment 同样能获取到application.properties配置的属性. System.out.println(env.getProperty("spring.datasource.url")); //获取到前缀是"spring.datasource." 的属性列表值. RelaxedPropertyResolver relaxedPropertyResolver = new RelaxedPropertyResolver(env, "spring.datasource."); System.out.println("spring.datasource.url="+relaxedPropertyResolver.getProperty("url")); System.out.println("spring.datasource.driverClassName="+relaxedPropertyResolver.getProperty("driverClassName")); } }
启动应用
@Controller@Service 等被Spring管理的类都支持，注意重写的方法setEnvironment 是在系统启动的时候被执行。
或者如下Controller：
package me.shijunjie.controller; import org.springframework.context.EnvironmentAware; import org.springframework.core.env.Environment; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController @RequestMapping("/test2") public class TestController implements EnvironmentAware { /*@Resource(name="TestAutoConfiguration2") private TestAutoConfiguration testAutoConfiguration;*/ @Override public void setEnvironment(Environment env) { String s= env.getProperty("JAVA_HOME"); System.out.println("JAVA_HOME2"+s); } @RequestMapping("/hello") public String test() { /*System.out.println(testAutoConfiguration.getDataSourceProperties().getName()); System.out.println(testAutoConfiguration.getDataSourceProperties().getPassword()); System.out.println(testAutoConfiguration.getDataSourceProperties().getUrl());*/ return "hello"; } }
启动应用
2.绑定属性对象
我们还可以通过@ConfigurationProperties 读取application属性配置文件中的属性。
package me.shijunjie.config; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import me.shijunjie.properties.DataSourceProperties; @Configuration @ConditionalOnClass(DataSourceProperties.class) @EnableConfigurationProperties(DataSourceProperties.class) public class TestAutoConfiguration { @Autowired private DataSourceProperties dataSourceProperties; @Bean(name="TestAutoConfiguration2") public TestAutoConfiguration setTestAutoConfiguration() { return this; } public DataSourceProperties getDataSourceProperties() { return dataSourceProperties; } public void setDataSourceProperties(DataSourceProperties dataSourceProperties) { this.dataSourceProperties = dataSourceProperties; } }
package me.shijunjie.properties; import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties(prefix = "spring.datasource") public class DataSourceProperties { private String url; private String name = "testName"; private String password; public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
@ConditionOnClass表明该@Configuration仅仅在一定条件下才会被加载，这里的条件是DataSourceProperties.class位于类路径上
@EnableConfigurationProperties将Spring Boot的配置文件（application.properties）中的spring.datasource.*属性映射为DataSourceProperties并注入到TestAutoConfiguration中。
@ConditionalOnMissingBean说明Spring Boot仅仅在当前上下文中不存在指定对象时，才会实例化一个Bean。这个逻辑也体现了Spring Boot的另外一个特性——自定义的Bean优先于框架的默认配置，我们如果显式的在业务代码中定义了一个对象，那么Spring Boot就不再创建。
测试
package me.shijunjie.controller; import javax.annotation.Resource; import org.springframework.context.EnvironmentAware; import org.springframework.core.env.Environment; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import me.shijunjie.config.TestAutoConfiguration; @RestController @RequestMapping("/test2") public class TestController implements EnvironmentAware { @Resource(name="TestAutoConfiguration2") private TestAutoConfiguration testAutoConfiguration; @Override public void setEnvironment(Environment env) { String s= env.getProperty("JAVA_HOME"); System.out.println("JAVA_HOME2"+s); } @RequestMapping("/hello") public String test() { System.out.println(testAutoConfiguration.getDataSourceProperties().getName()); System.out.println(testAutoConfiguration.getDataSourceProperties().getPassword()); System.out.println(testAutoConfiguration.getDataSourceProperties().getUrl()); return "hello"; } }
打开浏览器，输入地址http://localhost:8080/test2/hello
这里告诉我们DataSourceProperties就是以spring.datasource作为前缀的属性，然后通过名字直接映射为对象的属性，同时还包含了一些默认值。如果不配置，那么spring.datasource.username就是jdbc:mysql://123.206.228.200:3306/test
网上资料上写绑定属性对象需要添加依赖（我没有加）
<!--spring-boot-configuration:springboot 配置处理器; -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
这边是我的application.properties文件
########################################################
###datasource
########################################################
spring.datasource.url = jdbc:mysql://123.206.228.200:3306/test
spring.datasource.username = shijunjie
spring.datasource.password = *****
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.max-maxWait=100
spring.datasource.min-idle=8
spring.datasource.initial-size=10
[十六]SpringBoot 之 读取环境变量和绑定属性对象
标签：min end 获取 oid logs idle .com cep wait
原文地址：http://www.cnblogs.com/s648667069/p/6509258.html
