Spring Boot读取配置文件
1）通过注入ApplicationContext 或者 Environment对象来读取配置文件里的配置信息。
package com.ivan.config.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationContext;import org.springframework.core.env.Environment;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class ConfigController { @Autowired
ApplicationContext context; @Autowired
Environment environment; @RequestMapping(value="/config", method={RequestMethod.GET}) public String getConfigContent(){
String name = context.getEnvironment().getProperty("db.user.name"); return name;
} @RequestMapping(value="/configEnv", method={RequestMethod.GET}) public String getConfigEnvironment(){
String name = environment.getProperty("db.user.name"); return name;
}
}2）通过@ConfigurationProperties配合@PropertySource读取配置文件里的配置信息。
1：通过@PropertySource指定当前类里属性的配置文件地址，ConfigurationProperties可以指定配置的前缀，@Configuration用于定义一个配置类：
package com.ivan.config.entity;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.PropertySource;@Configuration@PropertySource("classpath:config/druid.properties")@ConfigurationProperties(prefix = "druid")public class DruidConfig { private int initialSize; private int minIdle; private int maxActive; private int maxWait; private String validationQuery; private boolean testWhileIdle; private boolean testOnBorrow; private boolean testOnReturn; public int getInitialSize() { return initialSize;
} public void setInitialSize(int initialSize) { this.initialSize = initialSize;
} public int getMinIdle() { return minIdle;
} public void setMinIdle(int minIdle) { this.minIdle = minIdle;
} public int getMaxActive() { return maxActive;
} public void setMaxActive(int maxActive) { this.maxActive = maxActive;
} public int getMaxWait() { return maxWait;
} public void setMaxWait(int maxWait) { this.maxWait = maxWait;
} public String getValidationQuery() { return validationQuery;
} public void setValidationQuery(String validationQuery) { this.validationQuery = validationQuery;
} public boolean isTestWhileIdle() { return testWhileIdle;
} public void setTestWhileIdle(boolean testWhileIdle) { this.testWhileIdle = testWhileIdle;
} public boolean isTestonBorrow() { return testOnBorrow;
} public void setTestonBorrow(boolean testOnBorrow) { this.testOnBorrow = testOnBorrow;
} public boolean isTestonReturn() { return testOnReturn;
} public void setTestonReturn(boolean testOnReturn) { this.testOnReturn = testOnReturn;
} @Override
public String toString() { return "DruidConfig [initialSize=" + initialSize + ", minIdle=" + minIdle + ", maxActive=" + maxActive + ", maxWait=" + maxWait + ", validationQuery=" + validationQuery + ", testWhileIdle=" + testWhileIdle + ", testonBorrow=" + testOnBorrow + ", testonReturn=" + testOnReturn + "]";
}
}2：对应的配置文件：
druid.initialSize=5 druid.minIdle=5 druid.maxActive=20 druid.maxWait=60000 druid.validationQuery=select 'x'druid.testWhileIdle=true druid.testonBorrow=true druid.testonReturn=true
3：在需要用到的类通过@Autowired注入
package com.ivan.config.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;import com.ivan.config.entity.DruidConfig;@RestControllerpublic class DruidConfigController { @Autowired
public DruidConfig druidConfig; @RequestMapping(value="/druidConfig", method={RequestMethod.GET}) public String getDruidConfig(){ return druidConfig.toString();
}
}3）通过@Value注解
1：需要得到配置属性的类如下，可以在任何需要得到配置的地方用@Value注解
package com.ivan.config.entity;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Configuration;@Configurationpublic class ValueTest { @Value("${db.user.name}") private String username; public String getUsername() { return username;
} public void setUsername(String username) { this.username = username;
}
}2：测试Controller类通过@Autowired注入实体类
package com.ivan.config.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;import com.ivan.config.entity.ValueTest;@RestControllerpublic class ValueController { @Autowired
private ValueTest value; @RequestMapping(value="/configValue", method={RequestMethod.GET}) public String getConfig(){ return value.getUsername();
}
}Spring boot 配置文件优先级:1：命令行参数。（以--开头的参数,比如可以设置：--server.port对同一套代码设置不同的参数）
2： 通过 System.getProperties() 获取的 Java 系统参数。
3：操作系统环境变量（这解释了为什么你通过application.properties设置的user.name取的是系统的用户名了）
4：从 java:comp/env 得到的 JNDI 属性。
5： 应用 Jar 文件之外的属性文件（系统的application.properties文件）
6：应用 Jar 文件内部的属性文件。
7： 在应用配置 Java 类（包含“@Configuration”注解的 Java 类）中通过“@PropertySource”注解声明的属性文件。
8： 通过“SpringApplication.setDefaultProperties”声明的默认属性。
作者：良辰美景TT
链接：https://www.jianshu.com/p/6fcd33551532
