如何避免在tomcat的server.xml中以明文形式存储密码？DataSource的资源定义？

keytool -genkey -alias tomcat -storetype JKS -keyalg RSA -keysize 2048 -keystore keystore.jks

keytool -genseckey -alias dbpassword -storetype JKS -keyalg AES -keysize 128 -keystore keystore.jks

<CredentialHandler className="org.apache.tomcat.util.buf.DigesterCredentialHandler"
                    algorithm="AES"
                    keyStoreFile="conf/keystore.jks"
                    keyStoreType="JKS"
                    keyAlias="dbpassword"
                    keyPass="your_key_pass" />

<Credential
    className="org.apache.tomcat.util.buf.DigesterCredentialHandler"
    algorithm="AES"
    keyStoreFile="conf/keystore.jks"
    keyStoreType="JKS"
    keyAlias="dbpassword"
    keyPass="your_key_pass" />

          auth="Container"
          type="javax.sql.DataSource"
          driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://localhost:3306/yourDatabase"
          username="yourUsername"
          password="yourPassword"
          factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
          initialSize="10"
          maxActive="100"
          maxIdle="20"
          minIdle="15"
          removeAbandoned="true"
          removeAbandonedTimeout="60"
          logAbandoned="true"
          validationQuery="SELECT 1"
          testOnBorrow="true"
          testWhileIdle="true"
          timeBetweenEvictionRunsMillis="30000"
          minEvictableIdleTimeMillis="60000"
          jmxEnabled="true"
          jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;
                              org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer" />