EnvironmentPostProcessor怎么做单元测试？阿里P7解答
简介
从Spring Boot 1.3开始，我们可以在应用程序上下文刷新之前使用EnvironmentPostProcessor来自定义应用程序的Environment。Environment表示当前应用程序运行的环境，它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、系统环境变量和Servlet上下文参数。使用EnvironmentPostProcessor可以在bean初始化之前对Environment进行修改。
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使用示例
让我们设想一个需求，配置文件中的数据库密码是加密后的密文，如：
spring.datasource.password=js8sbAwkduzPTEWQrlDbTw==
在应用启动时，对密文进行解密后再进行数据库的连接。
针对这种需求，就可以通过EnvironmentPostProcessor对密文进行解密，重新放到Environment中。
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1.实现EnvironmentPostProcessor
package one.more;import org.springframework.boot.SpringApplication;import org.springframework.boot.env.EnvironmentPostProcessor;import org.springframework.core.env.ConfigurableEnvironment;import org.springframework.core.env.PropertiesPropertySource;import java.util.Properties;public class DecodeEnvironmentPostProcessor implements EnvironmentPostProcessor { public static final String SPRING_DATASOURCE_PASSWORD = "spring.datasource.password"; public static final String AES_SECRET = "OneMore"; @Override public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) { String password = environment.getProperty(SPRING_DATASOURCE_PASSWORD); Properties properties = new Properties(); properties.setProperty(SPRING_DATASOURCE_PASSWORD, AESUtil.decrypt(password, AES_SECRET)); PropertiesPropertySource propertiesPropertySource = new PropertiesPropertySource(SPRING_DATASOURCE_PASSWORD, properties); environment.getPropertySources().addFirst(propertiesPropertySource); }}
如果你希望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
想要在Spring Boot启动过程中调用这个实现类，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
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单元测试
下面介绍本文的重点：怎么做EnvironmentPostProcessor实现类的单元测试，话不多说，直接上代码：
package one.more;import org.junit.Assert;import org.junit.Test;import org.springframework.boot.SpringApplication;import org.springframework.boot.WebApplicationType;import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.boot.env.EnvironmentPostProcessor;import org.springframework.context.ConfigurableApplicationContext;import org.springframework.core.env.ConfigurableEnvironment;import org.springframework.core.env.PropertiesPropertySource;import java.util.Properties;public class DecodeEnvironmentPostProcessorTest { @Test public void testPostProcessEnvironment() { DecodeEnvironmentPostProcessor processor = new DecodeEnvironmentPostProcessor(); String password = "one-more"; Properties properties = new Properties(); properties.setProperty(DecodeEnvironmentPostProcessor.SPRING_DATASOURCE_PASSWORD, AESUtil.encrypt(password, DecodeEnvironmentPostProcessor.AES_SECRET)); ConfigurableEnvironment environment = getEnvironment(processor, properties); Assert.assertEquals(password, environment.getProperty(DecodeEnvironmentPostProcessor.SPRING_DATASOURCE_PASSWORD)); } /** * 获取一个经过EnvironmentPostProcessor处理过的Environment * * @param processor EnvironmentPostProcessor实现类的实例 * @param properties 预置准备做单元测试的属性 * @return 处理过的Environment */ private ConfigurableEnvironment getEnvironment(EnvironmentPostProcessor processor, Properties properties) { // 创建一个SpringApplication SpringApplication springApplication = new SpringApplicationBuilder() .sources(DecodeEnvironmentPostProcessor.class) .web(WebApplicationType.NONE).build(); // 获取应用上下文 ConfigurableApplicationContext context = springApplication.run(); // 获取Environment ConfigurableEnvironment environment = context.getEnvironment(); //添加准备做单元测试的属性 environment.getPropertySources() .addFirst(new PropertiesPropertySource("test", properties)); processor.postProcessEnvironment(environment, springApplication); context.close(); return environment; }}
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附：加解密工具类代码
package one.more;import org.apache.commons.codec.binary.Base64;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;import java.security.NoSuchAlgorithmException;import java.security.SecureRandom;public class AESUtil { private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding"; private static final String KEY_ALGORITHM = "AES"; public static String encrypt(String content, String password) { try { Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM); byte[] byteContent = content.getBytes("utf-8"); cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(password)); byte[] result = cipher.doFinal(byteContent); return Base64.encodeBase64String(result); } catch (Exception ex) { } return null; } public static String decrypt(String content, String password) { try { Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, getSecretKey(password)); byte[] result = cipher.doFinal(Base64.decodeBase64(content)); return new String(result, "utf-8"); } catch (Exception ex) { } return null; } private static SecretKeySpec getSecretKey(final String password) { KeyGenerator kg = null; try { kg = KeyGenerator.getInstance(KEY_ALGORITHM); kg.init(128, new SecureRandom(password.getBytes())); SecretKey secretKey = kg.generateKey(); return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM); } catch (NoSuchAlgorithmException ex) { } return null; }}
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