springboot启动时替换配置参数

SpringBoot启动时配置参数替换

一.背景

SpringBoot项目启动的时候，在不使用配置中心等的前提下或者有公司强制使用指定的"密码箱"情况下，需要远程获取关键配置信息，比如数据库密码，则需要在项目启动前获取配置并且进行本地配置替换。

二.Demo实现

1.maven依赖

xml 复制代码

<dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

2.application.yml

yml 复制代码

spring:
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        druid:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
            username: root
            password: root
            initial-size: 10
            max-active: 100
            min-idle: 10
            max-wait: 60000
            pool-prepared-statements: true
            max-pool-prepared-statement-per-connection-size: 20
            time-between-eviction-runs-millis: 60000
            min-evictable-idle-time-millis: 300000
            #Oracle需要打开注释
            #validation-query: SELECT 1 FROM DUAL
            test-while-idle: true
            test-on-borrow: false
            test-on-return: false
            stat-view-servlet:
                enabled: true
                url-pattern: /druid/*
                #login-username: admin
                #login-password: admin
            filter:
                stat:
                    log-slow-sql: true
                    slow-sql-millis: 1000
                    merge-sql: false
                wall:
                    config:
                        multi-statement-allow: true

3.代码实现

实现SpringBoot的接口EnvironmentPostProcessor

java 复制代码

package com.zzc.config;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.env.EnvironmentPostProcessor;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.MutablePropertySources;
import java.util.HashMap;
import java.util.Map;

@Configuration
public class TestConfigEnvironmentProcessor implements EnvironmentPostProcessor {

    private static final Logger log = LoggerFactory.getLogger(TestConfigEnvironmentProcessor.class);

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
        String password = environment.getProperty("spring.datasource.druid.password");
        System.out.println("System TestConfigEnvironmentProcessor password: " + password);
        MutablePropertySources mutablePropertySources = environment.getPropertySources();
        //TODO 创建单例等http请求工具，获取密码箱等配置，替换本地关键的配置
        Map<String, Object> map = new HashMap<>();
        map.put("spring.datasource.druid.password", "123456");
        mutablePropertySources.addFirst(new MapPropertySource("test", map));//自定的配置名称和配置项
        password = environment.getProperty("spring.datasource.druid.password");
        System.out.println("System TestConfigEnvironmentProcessor password: " + password);
    }
}

4.spring.factories配置

在src/main/resources目录下创建文件夹META-INF，再创建文件spring.factories文件，新增配置项

base 复制代码

org.springframework.boot.env.EnvironmentPostProcessor=\
com.zzc.config.TestConfigEnvironmentProcessor