异常信息如下：

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.alibaba.druid.wall.WallProvider.checkInternal(WallProvider.java:707)
	at com.alibaba.druid.wall.WallProvider.check(WallProvider.java:584)
	at com.alibaba.druid.wall.WallFilter.checkInternal(WallFilter.java:826)
	at com.alibaba.druid.wall.WallFilter.check(WallFilter.java:821)
	at com.alibaba.druid.wall.WallFilter.statement_execute(WallFilter.java:454)
	at com.alibaba.druid.filter.FilterChainImpl.statement_execute(FilterChainImpl.java:3008)
	at com.alibaba.druid.filter.FilterAdapter.statement_execute(FilterAdapter.java:2484)
	at com.alibaba.druid.filter.FilterEventAdapter.statement_execute(FilterEventAdapter.java:188)
	at com.alibaba.druid.filter.FilterChainImpl.statement_execute(FilterChainImpl.java:3008)
	at com.alibaba.druid.proxy.jdbc.StatementProxyImpl.execute(StatementProxyImpl.java:147)
	at com.alibaba.druid.pool.vendor.MSSQLValidConnectionChecker.isValidConnection(MSSQLValidConnectionChecker.java:50)
	at com.alibaba.druid.pool.DruidAbstractDataSource.validateConnection(DruidAbstractDataSource.java:1398)

跟进去这个方法：com.alibaba.druid.pool.DruidAbstractDataSource.validateConnection

result = validConnectionChecker.isValidConnection(conn, validationQuery, validationQueryTimeout);

发现是这行代码报的异常，进入这个方法

找到这个实现类的方法（因为是sqlserver）

public boolean isValidConnection(final Connection c, String validateQuery, int validationQueryTimeout) throws Exception {
        if (c.isClosed()) {
            return false;
        }

        Statement stmt = null;

        try {
            stmt = c.createStatement();
            if (validationQueryTimeout > 0) {
                stmt.setQueryTimeout(validationQueryTimeout);
            }
            stmt.execute(validateQuery);
            return true;
        } catch (SQLException e) {
            throw e;
        } finally {
            JdbcUtils.close(stmt);
        }
    }

最终发现方法参数validateQuery是null，所以报了空指针，那我们回去看为什么是null

protected volatile String                          validationQuery                           = DEFAULT_VALIDATION_QUERY;

类定义了validationQuery等于DEFAULT_VALIDATION_QUERY，而DEFAULT_VALIDATION_QUERY初始化定义为null，其实这个参数来源与springboot配置文件

在springboot数据源配置文件新增下面这个配置：

druid:
                        validation-query: SELECT 1

就可以啦！

PS，数据源配置：

driver-class-name: com.microsoft.sqlserver.jdbc.SQLServerDriver
url: jdbc:sqlserver://IP:PORT;DatabaseName=库名
username: 数据库用户名
password: 密码
druid:
    validation-query: SELECT 1