mysql:
  driver: com.mysql.jdbc.Driver
  url: jdbc:mysql://localhost:3306/test?characterEncoding=utf8
  username: root
  password: 4545222   
  #一般為了信息安全，密碼都會(huì)配置成密文的，比如：password: PASSWORD[ 加密后的密文 ]

mysql:
  driver: com.mysql.jdbc.Driver
  url: jdbc:mysql://localhost:3306/test?characterEncoding=utf8
  username: root
  # BR23C92223KKDNUIQMPLS0009 為經(jīng)過(guò)加密處理的密碼
  password: PASSWORD[BR23C92223KKDNUIQMPLS0009]

package cn.yjh.listener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
import org.springframework.boot.env.OriginTrackedMapPropertySource;
import org.springframework.context.ApplicationListener;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import cn.yjh.util.EncryptUtil;
/**
 * @author YouJinhua
 * @since 2021/9/13 10:21
 */
public class EnvironmentPreparedListener implements ApplicationListener<ApplicationEnvironmentPreparedEvent> {
    @Override
    public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
        ConfigurableEnvironment env = event.getEnvironment();
        MutablePropertySources pss = env.getPropertySources();
        List<PropertySource> list = new ArrayList<>();
        for(PropertySource ps : pss){
            Map<String,Object>  map = new HashMap<>();
            if(ps instanceof OriginTrackedMapPropertySource){
                OriginTrackedMapPropertySource propertySource = new OriginTrackedMapPropertySource(ps.getName(),map);
                Map<String,Object> src = (Map<String,Object>)ps.getSource();
                src.forEach((k,v)->{
                    String strValue = String.valueOf(v);
                    if(strValue.startsWith("PASSWORD[") && strValue.endsWith("]")) {
                        // 此處進(jìn)行截取出對(duì)應(yīng)的密文 BR23C92223KKDNUIQMPLS0009 ,然后調(diào)用對(duì)應(yīng)的解密算法進(jìn)行解密操作
                        v = EncryptUtil.decrypt("work0", strValue.substring(9, strValue.length()-1));
                    }
                    map.put(k,v);
                });
                list.add(propertySource);
            }
        }
        /** 
            此處是刪除原來(lái)的 OriginTrackedMapPropertySource 對(duì)象，
            把解密后新生成的放入到 Environment,為什么不直接修改原來(lái)的
            OriginTrackedMapPropertySource 對(duì)象，此處不做過(guò)多解釋
            不懂的可以去看看它對(duì)應(yīng)的源碼，也算是留一個(gè)懸念，也是希望大家
            能夠沒(méi)事多看一看源碼。
        */
        list.forEach(ps->{
            pss.remove(ps.getName());
            pss.addLast(ps);
        });
    }
}

org.springframework.context.ApplicationListener=cn.yjh.listener.EnvironmentPreparedListener

# Application Listeners
org.springframework.context.ApplicationListener=cn.yjh.listener.EnvironmentPreparedListener

// 這個(gè)注解說(shuō)明是一個(gè)配置類(lèi)
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ TextEncryptor.class })
@EnableConfigurationProperties({ KeyProperties.class })
public class EncryptionBootstrapConfiguration {
	@Autowired(required = false)
	// 這個(gè)地方會(huì)從IOC容器中獲取上面我們提到的那個(gè)接口的實(shí)現(xiàn)類(lèi)，由于是required = false，所以不一定獲取得到，因?yàn)榭赡苋萜髦袥](méi)有這個(gè)對(duì)象
	private TextEncryptor encryptor;
	@Autowired
	private KeyProperties key;
	
	// 這里 spring IOC 容器添加一個(gè) EnvironmentDecryptApplicationInitializer  組件
	@Bean
	public EnvironmentDecryptApplicationInitializer environmentDecryptApplicationListener() {		
		// 這里判斷上面注入的 TextEncryptor  對(duì)象是否為空
		if (this.encryptor == null) {
			//為null，就創(chuàng)建一個(gè)默認(rèn)的
			this.encryptor = new FailsafeTextEncryptor();
		}
		// 否則使用上面注入的那個(gè) TextEncryptor  
		EnvironmentDecryptApplicationInitializer listener = new EnvironmentDecryptApplicationInitializer(
				this.encryptor);
		listener.setFailOnError(this.key.isFailOnError());
		return listener;
	}
	/**
		省略其他代碼，只看關(guān)鍵的
	*/
}

public class EnvironmentDecryptApplicationInitializer implements
		ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
	/** 
	    這里的 {cipher} 相當(dāng)于我們 springboot配置文件解密 的 PASSWORD[]
		  springcloud的配置格式是： '{cipher}BR23C92223KKDNUIQMPLS0009'
		  而我們的配置格式是：				PASSWORD[BR23C92223KKDNUIQMPLS0009]
		 	注意： '' 必須要加，不然yaml解析器，解析不了，會(huì)報(bào)錯(cuò)。
	*/
	public static final String ENCRYPTED_PROPERTY_PREFIX = "{cipher}";
	// 解密的對(duì)象
	private TextEncryptor encryptor;
	// 構(gòu)造函數(shù)，傳入解密對(duì)象，前一個(gè)配置類(lèi)傳入的
	public EnvironmentDecryptApplicationInitializer(TextEncryptor encryptor) {
		// 進(jìn)行屬性賦值
		this.encryptor = encryptor;
	}
	
	// 這個(gè)方法，我們看關(guān)鍵點(diǎn)
	private void merge(PropertySource<?> source, Map<String, Object> properties) {
		if (source instanceof CompositePropertySource) {
			List<PropertySource<?>> sources = new ArrayList<>(
					((CompositePropertySource) source).getPropertySources());
			Collections.reverse(sources);
			for (PropertySource<?> nested : sources) {
				merge(nested, properties);
			}
		}
		else if (source instanceof EnumerablePropertySource) {
			Map<String, Object> otherCollectionProperties = new LinkedHashMap<>();
			boolean sourceHasDecryptedCollection = false;
			EnumerablePropertySource<?> enumerable = (EnumerablePropertySource<?>) source;
			for (String key : enumerable.getPropertyNames()) {
				Object property = source.getProperty(key);
				if (property != null) {
					String value = property.toString();
					// 這里決定了我們，要使用 {cipher} 開(kāi)頭，表面我們是一個(gè)加密項(xiàng)
					if (value.startsWith(ENCRYPTED_PROPERTY_PREFIX)) {
						// 如何是加密項(xiàng)，放入properties對(duì)象中存起來(lái)，方便后面解密
						properties.put(key, value);
						if (COLLECTION_PROPERTY.matcher(key).matches()) {
							sourceHasDecryptedCollection = true;
						}
					}
					else if (COLLECTION_PROPERTY.matcher(key).matches()) {
						// put non-encrypted properties so merging of index properties
						// happens correctly
						otherCollectionProperties.put(key, value);
					}
					else {
						// override previously encrypted with non-encrypted property
						properties.remove(key);
					}
				}
			}
			// copy all indexed properties even if not encrypted
			if (sourceHasDecryptedCollection && !otherCollectionProperties.isEmpty()) {
				properties.putAll(otherCollectionProperties);
			}
		}
	}
	private void decrypt(Map<String, Object> properties) {
		properties.replaceAll((key, value) -> {
			String valueString = value.toString();
			if (!valueString.startsWith(ENCRYPTED_PROPERTY_PREFIX)) {
				return value;
			}
			return decrypt(key, valueString);
		});
	}
	
	// 這里是真正調(diào)用解密方法進(jìn)行解密了
	private String decrypt(String key, String original) {
		String value = original.substring(ENCRYPTED_PROPERTY_PREFIX.length());
		try {
			// 這里的 encryptor 對(duì)象就是構(gòu)造函數(shù)傳入的 TextEncryptor 
			value = this.encryptor.decrypt(value);
			if (logger.isDebugEnabled()) {
				logger.debug("Decrypted: key=" + key);
			}
			return value;
		}
		catch (Exception e) {
			String message = "Cannot decrypt: key=" + key;
			if (logger.isDebugEnabled()) {
				logger.warn(message, e);
			}
			else {
				logger.warn(message);
			}
			if (this.failOnError) {
				throw new IllegalStateException(message, e);
			}
			return "";
		}
	}
}

package cn.yjh.listener;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.context.event.ApplicationPreparedEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.security.crypto.encrypt.TextEncryptor;
/**
 * @author YouJinhua
 * @since 2021/9/13 9:10
 */
public class RegisterTextEncryptorListener implements ApplicationListener<ApplicationPreparedEvent>, Ordered {
    @Override
    public void onApplicationEvent(ApplicationPreparedEvent event) {
        ConfigurableApplicationContext applicationContext = event.getApplicationContext();
        // 這里回往spring IOC 中添加好幾次，是因?yàn)楦缸尤萜鞯脑?，所以要判斷一?
        if(applicationContext instanceof AnnotationConfigApplicationContext){
            ConfigurableListableBeanFactory beanFactory = applicationContext.getBeanFactory();
            // 這里判斷是否已經(jīng)添加過(guò)我們自己的解密算法了，沒(méi)添加才添加，否則跳過(guò)
            if(!beanFactory.containsBean("textEncryptor")){
                beanFactory.registerSingleton("textEncryptor",new TextEncryptor(){
                    @Override
                    public String encrypt(String text) {
                        System.out.println("=====================================加密");
                        return "加密"+text;
                    }
                    @Override
                    public String decrypt(String encryptedText) {
                    	  //這里解密就直接輸出日志，然后直接解密返回
                        System.out.println("=====================================解密");
                        return EncryptUtil.decrypt("work0", encryptedText);
                    }
                });
            }
        }
    }
    @Override
    public int getOrder() {
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

org.springframework.context.ApplicationListener=cn.yjh.listener.RegisterTextEncryptorListener

mysql:
  driver: com.mysql.jdbc.Driver
  url: jdbc:mysql://localhost:3306/test?characterEncoding=utf8
  username: root
  # BR23C92223KKDNUIQMPLS0009 為經(jīng)過(guò)加密處理的密碼,注意一定要加 '' 否則解析yaml會(huì)報(bào)錯(cuò)  
  password: '{cipher}BR23C92223KKDNUIQMPLS0009'