详解Spring Boot读取配置文件与配置文件优先级
SpringBoot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。
packagecom.ivan.config.controller;
importorg.springframework.beans.factory.annotation.Autowired;
importorg.springframework.context.ApplicationContext;
importorg.springframework.core.env.Environment;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.RequestMethod;
importorg.springframework.web.bind.annotation.RestController;
@RestController
publicclassConfigController{
@Autowired
ApplicationContextcontext;
@Autowired
Environmentenvironment;
@RequestMapping(value="/config",method={RequestMethod.GET})
publicStringgetConfigContent(){
Stringname=context.getEnvironment().getProperty("db.user.name");
returnname;
}
@RequestMapping(value="/configEnv",method={RequestMethod.GET})
publicStringgetConfigEnvironment(){
Stringname=environment.getProperty("db.user.name");
returnname;
}
}
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：
packagecom.ivan.config.entity;
importorg.springframework.boot.context.properties.ConfigurationProperties;
importorg.springframework.context.annotation.Configuration;
importorg.springframework.context.annotation.PropertySource;
@Configuration
@PropertySource("classpath:config/druid.properties")
@ConfigurationProperties(prefix="druid")
publicclassDruidConfig{
privateintinitialSize;
privateintminIdle;
privateintmaxActive;
privateintmaxWait;
privateStringvalidationQuery;
privatebooleantestWhileIdle;
privatebooleantestOnBorrow;
privatebooleantestOnReturn;
publicintgetInitialSize(){
returninitialSize;
}
publicvoidsetInitialSize(intinitialSize){
this.initialSize=initialSize;
}
publicintgetMinIdle(){
returnminIdle;
}
publicvoidsetMinIdle(intminIdle){
this.minIdle=minIdle;
}
publicintgetMaxActive(){
returnmaxActive;
}
publicvoidsetMaxActive(intmaxActive){
this.maxActive=maxActive;
}
publicintgetMaxWait(){
returnmaxWait;
}
publicvoidsetMaxWait(intmaxWait){
this.maxWait=maxWait;
}
publicStringgetValidationQuery(){
returnvalidationQuery;
}
publicvoidsetValidationQuery(StringvalidationQuery){
this.validationQuery=validationQuery;
}
publicbooleanisTestWhileIdle(){
returntestWhileIdle;
}
publicvoidsetTestWhileIdle(booleantestWhileIdle){
this.testWhileIdle=testWhileIdle;
}
publicbooleanisTestOnBorrow(){
returntestOnBorrow;
}
publicvoidsetTestOnBorrow(booleantestOnBorrow){
this.testOnBorrow=testOnBorrow;
}
publicbooleanisTestOnReturn(){
returntestOnReturn;
}
publicvoidsetTestOnReturn(booleantestOnReturn){
this.testOnReturn=testOnReturn;
}
@Override
publicStringtoString(){
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
packagecom.ivan.config.controller;
importorg.springframework.beans.factory.annotation.Autowired;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.RequestMethod;
importorg.springframework.web.bind.annotation.RestController;
importcom.ivan.config.entity.DruidConfig;
@RestController
publicclassDruidConfigController{
@Autowired
publicDruidConfigdruidConfig;
@RequestMapping(value="/druidConfig",method={RequestMethod.GET})
publicStringgetDruidConfig(){
returndruidConfig.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
packagecom.ivan.config.entity;
importorg.springframework.beans.factory.annotation.Value;
importorg.springframework.context.annotation.Configuration;
@Configuration
publicclassValueTest{
@Value("${db.user.name}")
privateStringusername;
publicStringgetUsername(){
returnusername;
}
publicvoidsetUsername(Stringusername){
this.username=username;
}
}
2：测试Controller类通过@Autowired注入实体类
packagecom.ivan.config.controller;
importorg.springframework.beans.factory.annotation.Autowired;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.RequestMethod;
importorg.springframework.web.bind.annotation.RestController;
importcom.ivan.config.entity.ValueTest;
@RestController
publicclassValueController{
@Autowired
privateValueTestvalue;
@RequestMapping(value="/configValue",method={RequestMethod.GET})
publicStringgetConfig(){
returnvalue.getUsername();
}
}
Springboot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。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持毛票票。