Spring Boot 2 读取配置文件

2019-09-30 06:49:24来源:博客园 阅读 ()

Spring Boot 2 读取配置文件

开发环境:IntelliJ IDEA 2019.2.2
Spring Boot版本:2.1.8

新建一个名称为demo的Spring Boot项目。

一、默认配置文件

Spring Boot会读取名称application.properties(yml)的配置文件。
如果有多个同名文件,默认情况下,按照下面顺序读取:
(1)项目根目录的config目录
(2)项目根目录
(3)项目classpath下的config目录
(4)项目classpath根目录
如果同一个配置项出现在多份配置文件中,后面读取的值不会覆盖前面的。

测试:
在项目的4个位置各建立application.properties,内容如下:
(1)config/application.properties

test = config/application.properties
test1 = test1

(2)application.properties

test = application.properties
test2 = test2

(3)src/main/resources/config/application.properties

test = src/main/resources/config/application.properties
test3 = test3

(4)src/main/resources/application.properties

test = src/main/resources/application.properties
test4 = test4

 修改默认生成的启动类 DemoApplication.java 代码:

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Autowired
    private Environment env;

    @RequestMapping("/")
    public String getProp(){
        String test = env.getProperty("test");
        String test1 = env.getProperty("test1");
        String test2 = env.getProperty("test2");
        String test3 = env.getProperty("test3");
        String test4 = env.getProperty("test4");
        return test + "," + test1 + "," + test2 + "," + test3 + "," + test4;
    }
}

访问 http://localhost:8080/
输出:config/application.properties,test1,test2,test3,test4

二、指定配置文件

读取指定的配置文件,不使用默认的application.properties。

测试:
(1)src/main/resources/application.properties 内容:

test1 = application.properties

(2)在项目的src/main/resources新建目录config,新建配置文件myConfig.properties,内容:

test2= myConfig.properties

修改默认生成的启动类 DemoApplication.java 代码:

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class DemoApplication {

    public static void main(String[] args) {
        //SpringApplication.run(DemoApplication.class, args);
        new SpringApplicationBuilder(DemoApplication.class).properties(
                "spring.config.location=classpath:/config/myConfig.properties"
        ).run(args);
    }

    @Autowired
    private Environment env;

    @RequestMapping("/")
    public String getProp(){
        String test1 = env.getProperty("test1");
        String test2 = env.getProperty("test2");
        return test1 + "," + test2;
    }
}

访问 http://localhost:8080/
输出:null,myConfig.properties
可见application.properties已读取不到,成功读取到配置文件myConfig.properties。

也可以使用spring.config.name指定配置文件的名称,如下面代码指定了myConfig,Spring Boot会到classpath下寻找myConfig.properties(yml)。

    public static void main(String[] args) {
        //SpringApplication.run(DemoApplication.class, args);
        /*new SpringApplicationBuilder(DemoApplication.class).properties(
                "spring.config.location=classpath:/config/myConfig.properties"
        ).run(args);*/
        new SpringApplicationBuilder(DemoApplication.class).properties(
                "spring.config.name=myConfig").run(args);
    }

三、使用profile指定配置

使用profile可以根据特定的环境来激活不同的配置。

src/main/resources/application.yml 内容如下:

spring:
  profiles: mysql
jdbc:
  driver:
    com.mysql.jdbc.Driver
---
spring:
  profiles: oracle
jdbc:
  driver:
    oracle.jdbc.driver.OracleDriver

修改默认生成的启动类 DemoApplication.java 代码:

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Scanner;

@SpringBootApplication
@RestController
public class DemoApplication {

    public static void main(String[] args) {
        //SpringApplication.run(DemoApplication.class, args);

        Scanner scan = new Scanner(System.in);
        String profile = scan.nextLine();
        new SpringApplicationBuilder(DemoApplication.class).properties(
                "spring.config.location=classpath:/application.yml"
        ).profiles(profile).run(args);
    }

    @Autowired
    private Environment env;

    @RequestMapping("/")
    public String getProp(){
        String res = env.getProperty("jdbc.driver");
        return res;
    }
}

在IDEA中点击Run按钮后,在控制台先敲回车再输入oracle,
访问 http://localhost:8080/ 输出:oracle.jdbc.driver.OracleDriver
重新Run,在控制台先敲回车再输入mysql,
访问 http://localhost:8080/ 输出:com.mysql.jdbc.Driver

还可以通过不同配置文件的名称来设置profile,创建下面3个文件。
(1)src/main/resources/application.yml 内容:

spring:
  profiles:
    active: oracle

(2)src/main/resources/application-mysql.yml 内容:

jdbc:
  driver:
    com.mysql.jdbc.Driver

(3)src/main/resources/application-oracle.yml 内容:

jdbc:
  driver:
    oracle.jdbc.driver.OracleDriver

 修改默认生成的启动类 DemoApplication.java 代码:

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Scanner;

@SpringBootApplication
@RestController
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);     
    }

    @Autowired
    private Environment env;

    @RequestMapping("/")
    public String getProp(){
        String res = env.getProperty("jdbc.driver");
        return res;
    }
}

访问 http://localhost:8080/ 输出:oracle.jdbc.driver.OracleDriver


原文链接:https://www.cnblogs.com/gdjlc/p/11575743.html
如有疑问请与原作者联系

标签:QwebIEmysqlSQLHTTP

版权申明:本站文章部分自网络,如有侵权,请联系:west999com@outlook.com
特别注意:本站所有转载文章言论不代表本站观点,本站所提供的摄影照片,插画,设计作品,如需使用,请与原作者联系,版权归原作者所有

上一篇:浅谈JVM

下一篇:SpringBoot整合SSM