关于springboot:springbootmybatisplusdruid数据源SQLException问题

当我尝试应用数据源拜访mysql时，产生了这样的异样：

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:965) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3978) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3914) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1714) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1224) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2199) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_181]    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_181]    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_181]    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_181]    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) ~[mysql-connector-java-5.1.47.jar:5.1.47]    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1596) ~[druid-1.1.16.jar:1.1.16]    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1662) ~[druid-1.1.16.jar:1.1.16]    at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2601) ~[druid-1.1.16.jar:1.1.16]2022-05-27 17:45:02.559 ERROR 31428 --- [eate-1875532039] com.alibaba.druid.pool.DruidDataSource   : create connection SQLException, url: jdbc:mysql://localhost:3306/db2022?useUnicode=true&characterEncoding=utf-8&useSSL=false, errorCode 1045, state 28000

起因很低级：application.yml内容：

spring:  datasource:    driver-class-name: com.mysql.jdbc.Driver    url: jdbc:mysql://localhost:3306/db2022?useUnicode=true&characterEncoding=utf-8&useSSL=false    username: root    password: 0123    type: com.alibaba.druid.pool.DruidDataSource

改成 application.properties就能够，那是什么起因呢？
很简略： 0123这个明码，被yml解析成非字符串了， 加个双引号就好了，e不easy?
password: "0123"