项目场景：

在项目Hutool-db-DSFactory-数据池及多源配置
更改配置文件时，mariadb成功连接，sqlserver提示错误
各依赖版本：

		<!--引入Hutool依赖-->
		<dependency>
			<groupId>cn.hutool</groupId>
			<artifactId>hutool-all</artifactId>
			<version>5.7.2</version>
		</dependency>

		<!--引入mariadb驱动依赖-->
		<dependency>
			<groupId>org.mariadb.jdbc</groupId>
			<artifactId>mariadb-java-client</artifactId>
			<version>2.1.2</version>
		</dependency>

		<!-- 引入druid依赖 -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid</artifactId>
			<version>1.2.6</version>
		</dependency>

		<!-- 引入sqlserver依赖 -->
		<dependency>
			<groupId>com.microsoft.sqlserver</groupId>
			<artifactId>mssql-jdbc</artifactId>
			<version>9.2.1.jre8</version>
		</dependency>

问题描述：

提示报错如下：
ERROR com.alibaba.druid.pool.DruidDataSource - create connection SQLException
java.sql.SQLException: validateConnection false

16:49:59.835 [Druid-ConnectionPool-Create-329645619] ERROR com.alibaba.druid.pool.DruidDataSource - create connection SQLException, url: jdbc:sqlserver://192.168.205.131:1433;DatabaseName=testmssql, errorCode 0, state null
java.sql.SQLException: validateConnection false
        at com.alibaba.druid.pool.DruidAbstractDataSource.validateConnection(DruidAbstractDataSource.java:1418)
        at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1733)
        at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2801)
Caused by: java.lang.NullPointerException: null
        at com.microsoft.sqlserver.jdbc.SQLServerStatement.ensureSQLSyntax(SQLServerStatement.java:778)
        at com.microsoft.sqlserver.jdbc.SQLServerStatement.doExecuteStatement(SQLServerStatement.java:822)
        at com.microsoft.sqlserver.jdbc.SQLServerStatement$StmtExecCmd.doExecute(SQLServerStatement.java:767)
        at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:7418)
        at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:3272)
        at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeCommand(SQLServerStatement.java:247)
        at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeStatement(SQLServerStatement.java:222)
        at com.microsoft.sqlserver.jdbc.SQLServerStatement.execute(SQLServerStatement.java:743)
        at com.alibaba.druid.pool.vendor.MSSQLValidConnectionChecker.isValidConnection(MSSQLValidConnectionChecker.java:50)
        at com.alibaba.druid.pool.DruidAbstractDataSource.validateConnection(DruidAbstractDataSource.java:1398)
        ... 2 common frames omitted

原因分析：

Druid 与 sqlserver 驱动不兼容

解决方案：

更换druid版本或者sqlserver驱动版本
最后成功方案为：降低druid版本：1.2.6 → 1.2.5

<!-- 引入druid依赖 -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid</artifactId>
			<version>1.2.5</version>
		</dependency>