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详解Spring Boot读取配置文件与配置文件优先级

程序员文章站 2024-02-22 11:08:34
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。 packag...

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;

@restcontroller

public 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;
@restcontroller
public 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;
@configuration

public 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;
@restcontroller
public 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。

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。