简介从SpringBoot1.3开始，我们可以在应用上下文刷新之前，使用EnvironmentPostProcessor自定义应用的Environment。Environment表示当前应用程序运行的环境，可以统一访问各种属性源中的属性，如属性文件、JVM系统属性、系统环境变量、Servlet上下文参数等。EnvironmentPostProcessor可用于在bean初始化之前修改环境。示例让我们想象一个需求。配置文件中的数据库密码为加密密文，如：spring.datasource.password=js8sbAwkduzPTEWQrlDbTw==应用启动时，先解密密文再连接数据库。针对这个需求，可以通过EnvironmentPostProcessor对密文进行解密，放回Environment中。1.实际环境后处理器包一.更多；导入org.springframework.boot.SpringApplication；导入org.springframework.boot.env.EnvironmentPostProcessor；导入org.springframework.core.env.ConfigurableEnvironment；导入org.springframework.core.env.PropertiesPropertySource；importjava.util.Properties;publicclassDecodeEnvironmentPostProcessorimplementsEnvironmentPostProcessor{publicstaticfinalStringSPRING_DATASOURCE_PASSWORD="spring.datasource.password";publicstaticfinalStringAES_SECRET="OneMore";@OverridepublicvoidpostProcessEnvironment(ConfigurableEnvironmentenvironment,SpringApplicationapplication){Stringpassword=environment.getProperty(SPRING_DATASOURCE_PASSWORD);属性properties=newProperties();properties.setProperty(SPRING_DATASOURCE_PASSWORD,AESUtil.decrypt(密码,AES_SECRET));PropertiesPropertySourcepropertiesPropertySource=新PpropertiesPropertySource（SPRING_DATASOURCE_PASSWORD，属性）；environment.getPropertySources().addFirst(propertiesPropertySource);}}如果希望EnvironmentPostProcessor按照特定的顺序被调用，可以实现Ordered接口，或者使用@Order注解2.注册实现类在SpringBoot启动过程中要调用这个实现类，我们还需要在META-INF/Spring.factories中注册这个实现类：org.springframework.boot.env.EnvironmentPostProcessor=one.more.DecodeEnvironmentPostProcessor单元测试下面介绍本文的重点：如何对EnvironmentPostProcessor实现类进行单元测试，废话少说，直接上传代码：packageone.more;importorg.junit.Assert;importorg.junit。测试；导入org.springframework。boot.SpringApplication；导入org.springframework.boot.WebApplicationType；导入org.springframework.boot.builder.SpringApplicationBuilder；导入org.springframework.boot.env.EnvironmentPostProcessor；导入org.springframework.context.ConfigurableApplicationContext；导入orgwork.springreframe.env.ConfigurableEnvironment；导入org.springframework.core.env.PropertiesPropertySource；导入java.util.Properties；公共类DecodeEnvironmentPostProcessorTest{@TestpublicvoidtestPostProcessEnvironment(){DecodeEnvironmentPostProcessor处理器=newDecodeEncvironment=newDecodeEncvironment;多一个";Propertiesproperties=newProperties();properties.setProperty(DecodeEnvironmentPostProcessor.SPRING_DATASOURCE_PASSWORD,AESUtil.encrypt(password,DecodeEnvironmentPostProcessor.AES_SECRET));ConfigurableEnvironmentenvironmentpro=getEnvironment.Asspert,Assperts(processor)environment.getProperty(DecodeEnvironmentPostProcessor.SPRING_DATASOURCE_PASSWORD));}/***得到一个EnvironmentPostProcessor处理过的Environment**@paramprocessorEnvironmentPostProcessor实现类的一个实例*@parampropertiespresetpropertiesreadyforunittesting*@returnprocessedEnvironment*/privateConfigurableEnvironmentgetEnvironment(EnvironmentPostProcessorprocessor,Propertiesproperties){//创建一个SpringApplicationSpringApplicationspringApplication=newSpringApplicationBuilder().sources(DecodeEnvironmentPostProcessor.class).web(WebApplicationType.NONE).build();//获取应用上下文ConfigurableApplicationContextcontext=springApplication.run();//获取环境ConfigurableEnvironmentenvironment=context.getEnvironment();//添加单元测试的属性environment.getPropertySources().addFirst(newPropertiesPropertySource("test",properties));processor.postProcessEnvironment（环境，springApplication）；上下文.close();回归环境；}}附：加解密工具类代码包one.more;importorg.apache.commons.codec.binary.Base64;importjavax.crypto.Cipher;importjavax.crypto.KeyGenerator;importjavax.crypto.SecretKey;importjavax.crypto.spec.SecretKeySpec；导入java.security.NoSuchAlgorithmException；导入java.security.SecureRandom；publicclassAESUtil{privatestaticfinalStringDEFAULT_CIPHER_ALGORITHM="AES/ECB/PKCS5Padding";私人静态最终字符串KEY_ALGORITHM=“AES”；publicstaticStringencrypt(Stringcontent,Stringpassword){try{Ciphercipher=Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);byte[]byteContent=content.getBytes("utf-8");cipher.init(Cipher.ENCRYPT_MODE,getSecretKey(密码));byte[]result=cipher.doFinal(byteContent);返回Base64.encodeBase64String（结果）；}catch(Exceptionex){}返回null；}publicstaticStringdecrypt(Stringcontent,Stringpassword){try{Ciphercipher=Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE,getSecretKey(密码));byte[]result=cipher.doFinal(Base64.decodeBase64(content));返回新字符串（结果，“utf-8”）；}catch(Exceptionex){}返回null；}privatestaticSecretKeySpecgetSecretKey（最终字符串密码）{密钥生成器kg=null；尝试{kg=KeyGenerator.getInstance(KEY_ALGORITHM);kg.init(128,newSecureRandom(password.getBytes()));SecretKeysecretKey=kg.generateKey();返回新的SecretKeySpec(secretKey.getEncoded(),KEY_ALGORITHM);}catch(NoSuchAlgorithmExceptionex){}返回null；}}
