Spring——15使用@PropertySource加载配置文件

Posted 2022-12-18

文章目录

• ​​1、PropertySource介绍​​
• ​​2、使用​​

• ​​2.1、pom​​
• ​​2.2、yml​​
• ​​2.3、后置处理器​​
• ​​2.4、启动类​​

1、PropertySource介绍

通过@PropertySource注解可以将properties配置文件中的key/value存储到Spring的Environment中，Environment接口提供了方法去读取配置文件中的值，参数是properties配置文件中定义的key值。

其源代码如下:

细心的朋友，应该发现其里面还有个@PropertySources注解了吧，是不是跟@ComponentScan一样了，具体的大家可以回顾前面讲的@ComponentScan的详解，他就是个复用注解，代表我们的@PropertySource可以用多个。

2、使用

• PropertySource

• 添加 PropertySource

• context:property-placeholder
• PropertySourcesPlaceholderConfigurer

• PropertyPlaceholderConfigurer

• @PropertySource
• @PropertySources

• Spring Boot 中的 @ConfigurationProperties

• 可以将属性绑定到结构化对象上
• ⽀持 Relaxed Binding
• ⽀持安全的类型转换
• @EnableConfigurationProperties

• 定制 PropertySource

• 主要步骤

• 实现 PropertySource
• 从 Environment 取得 PropertySources
• 将⾃⼰的 PropertySource 添加到合适的位置

• 切⼊位置

• EnvironmentPostProcessor
• BeanFactoryPostProcessor

作用：可以用于读取配置文件，比如我们正常的nacos就是用这个做的。

2.1、pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.zhz</groupId>
    <artifactId>spring-boot-property-source-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-property-source-demo</name>
    <description>Spring Boot集成PropertySource</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.2、yml

resource/yapf.properties

spring.boot.zhz.property.source=hello

resource/META-INF/spring.factories

org.springframework.boot.env.EnvironmentPostProcessor=com.zhz.springbootpropertysourcedemo.processor.YapfEnvironmentPostProcessor

2.3、后置处理器

package com.zhz.springbootpropertysourcedemo.processor;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.env.EnvironmentPostProcessor;
import org.springframework.boot.env.PropertiesPropertySourceLoader;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

/**
 * @author zhouhengzhe
 * @Description: TODO
 * @sign: 代码虐我千百遍，我视代码如初恋
 * @date 2021/8/25上午12:51
 */
@Slf4j
public class YapfEnvironmentPostProcessor implements EnvironmentPostProcessor 
    private PropertiesPropertySourceLoader loader=new PropertiesPropertySourceLoader();

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) 
        MutablePropertySources propertySources = environment.getPropertySources();
        Resource resource = new ClassPathResource("yapf.properties");
        try 
            PropertySource ps = loader.load("YetAnotherPropertiesFile", resource).get(0);
            propertySources.addFirst(ps);
         catch (Exception e) 
            log.error("Exception!", e);
        
    

2.4、启动类

package com.zhz.springbootpropertysourcedemo;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author mac
 */
@Slf4j
@SpringBootApplication
public class SpringBootPropertySourceDemoApplication implements ApplicationRunner 

    @Value("$spring.boot.zhz.property.source")
    private String propertySource;

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

    @Override
    public void run(ApplicationArguments args) throws Exception 
        log.info("",propertySource);