從Spring Boot 1.3開始,我們可以在應(yīng)用程序上下文刷新之前使用EnvironmentPostProcessor
來自定義應(yīng)用程序的Environment
。Environment
表示當(dāng)前應(yīng)用程序運行的環(huán)境,它可以統(tǒng)一訪問各種屬性源中的屬性,如屬性文件、JVM系統(tǒng)屬性、系統(tǒng)環(huán)境變量和Servlet上下文參數(shù)。使用EnvironmentPostProcessor
可以在bean初始化之前對Environment
進(jìn)行修改。
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讓我們設(shè)想一個需求,配置文件中的數(shù)據(jù)庫密碼是加密后的密文,如:
spring.datasource.password=js8sbAwkduzPTEWQrlDbTw==
在應(yīng)用啟動時,對密文進(jìn)行解密后再進(jìn)行數(shù)據(jù)庫的連接。
針對這種需求,就可以通過EnvironmentPostProcessor
對密文進(jìn)行解密,重新放到Environment
中。
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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
按照特定的順序被調(diào)用,可以實現(xiàn)Ordered
接口,或者使用@Order
注解。
想要在Spring Boot啟動過程中調(diào)用這個實現(xiàn)類,我們還需要在META-INF/ Spring .factories
中注冊這個實現(xiàn)類:
org.springframework.boot.env.EnvironmentPostProcessor= one.more.DecodeEnvironmentPostProcessor
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下面介紹本文的重點:怎么做EnvironmentPostProcessor
實現(xiàn)類的單元測試,話不多說,直接上代碼:
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)); } /** * 獲取一個經(jīng)過EnvironmentPostProcessor處理過的Environment * * @param processor EnvironmentPostProcessor實現(xiàn)類的實例 * @param properties 預(yù)置準(zhǔn)備做單元測試的屬性 * @return 處理過的Environment */ private ConfigurableEnvironment getEnvironment(EnvironmentPostProcessor processor, Properties properties) { // 創(chuàng)建一個SpringApplication SpringApplication springApplication = new SpringApplicationBuilder() .sources(DecodeEnvironmentPostProcessor.class) .web(WebApplicationType.NONE).build(); // 獲取應(yīng)用上下文 ConfigurableApplicationContext context = springApplication.run(); // 獲取Environment ConfigurableEnvironment environment = context.getEnvironment(); //添加準(zhǔn)備做單元測試的屬性 environment.getPropertySources() .addFirst(new PropertiesPropertySource("test", properties)); processor.postProcessEnvironment(environment, springApplication); context.close(); return environment; }}
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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; }}