继承PropertyPlaceholderConfigurer 以动态改变配置文件内容

package com.light.ac.common.configuration;

import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;

import com.light.ac.common.util.DESUtil;

public class EncryptPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer {
	// 需要解密的字段
	private String[] encryptPropNames = { "jdbc.username", "jdbc.password" };

	@Override
	protected String convertProperty(String propertyName, String propertyValue) {
		if (isEncryptProp(propertyName)) {
			String decryptValue = DESUtil.getDecryptString(propertyValue);
			return decryptValue;
		} else {
			return propertyValue;
		}
	}

	private boolean isEncryptProp(String propertyName) {
		for (String encryptpropertyName : encryptPropNames) {
			if (encryptpropertyName.equals(propertyName))
				return true;
		}
		return false;
	}
}

<bean class="com.light.ac.common.configuration.EncryptPropertyPlaceholderConfigurer">
		<property name="locations">
			<list>
				<value>classpath:db.properties</value>
			</list>
		</property>
		<property name="fileEncoding" value="UTF-8"/>
	</bean>

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/authority-control?characterEncoding=utf-8&allowMultiQueries=true&serverTimezone=UTC
jdbc.username=WnplV/ietfQ=
jdbc.password=WnplV/ietfQ=

package com.light.ac.common.util;

import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class DESUtil {

	private static Key key;
	private static String KEY_STR = "myKey";
	private static String CHARSETNAME = "UTF-8";
	private static String ALGORITHM = "DES";

	static {
		try {
			KeyGenerator generator = KeyGenerator.getInstance(ALGORITHM);
			SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
			secureRandom.setSeed(KEY_STR.getBytes());
			generator.init(secureRandom);
			key = generator.generateKey();
			generator = null;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * 加密
	 * @param str
	 * @return
	 */
	public static String getEncryptString(String str) {
		BASE64Encoder base64encoder = new BASE64Encoder();
		try {
			byte[] bytes = str.getBytes(CHARSETNAME);
			Cipher cipher = Cipher.getInstance(ALGORITHM);
			cipher.init(Cipher.ENCRYPT_MODE, key);
			byte[] doFinal = cipher.doFinal(bytes);
			return base64encoder.encode(doFinal);
		} catch (Exception e) {
			// TODO: handle exception
			throw new RuntimeException(e);
		}
	}

	/**
	 * 解密
	 * @param str
	 * @return
	 */
	public static String getDecryptString(String str) {
		BASE64Decoder base64decoder = new BASE64Decoder();
		try {
			byte[] bytes = base64decoder.decodeBuffer(str);
			Cipher cipher = Cipher.getInstance(ALGORITHM);
			cipher.init(Cipher.DECRYPT_MODE, key);
			byte[] doFinal = cipher.doFinal(bytes);
			return new String(doFinal, CHARSETNAME);
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	public static void main(String[] args) {
		System.out.println(getEncryptString("root"));
		System.out.println(getEncryptString("tiger"));
		System.out.println(getDecryptString("WnplV/ietfQ="));
		System.out.println(getDecryptString("xyHEykQVHqA="));
	}

}