之所以把数据库的连接、结构、最小初始化等检查项放到SpringBoot监听器而不是Spring容器的初始过程。是有原因的。
1：SpringBoot监听器是SpringBoot初始化过程中，最先被执行的那一批周期函数。
2：数据库连接测试能很快的获得结果。
3：Spring容器初始化时，里面的ApplicationListener,ApplicationRunner,初始化方法等有部分实现是异步预热缓存数据。如果不前置检查数据表结构，很容易报sql异常。当产品有更新表结构时，项目发布时，很容易出现该问题。

public class PrepareTableCheckListener implements SpringApplicationRunListener {private static List<String> MYSQL_PRODUCT_NAMES = new ArrayList<>();static {MYSQL_PRODUCT_NAMES.add("kingbase8");MYSQL_PRODUCT_NAMES.add("mysql");}public PrepareTableCheckApplicationRunListener(SpringApplication application, String[] args) {}@Overridepublic void contextPrepared(ConfigurableApplicationContext context) {ConfigurableEnvironment environment = context.getEnvironment();String jdbcDriver = environment.getProperty("spring.datasource.driver-class-name");String jdbcUrl = environment.getProperty("spring.datasource.url");String jdbcUserName = environment.getProperty("spring.datasource.username");String jdbcUserPassword = environment.getProperty("spring.datasource.password");String testNetworkSQL = environment.getProperty("spring.datasource.hikari.connection-test-query");if (null == jdbcUrl || null == jdbcUserPassword || null == jdbcUserName) {return;}loadDriverClass(jdbcDriver);// 数据库连接检查DriverManager.setLoginTimeout(2);try (Connection conn = DriverManager.getConnection(jdbcUrl, jdbcUserName, jdbcUserPassword)) {Statement statement = conn.createStatement();statement.execute(testNetworkSQL);} catch (Exception e) {log.warn("+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+");log.warn("...................★");log.warn("..................▍..★");log.warn("..................▍.一 .☆");log.warn("................. ▍ ..帆. ★");log.warn("..................▍ ... 风. ☆");log.warn("..................▍ ... ..顺. ★");log.warn("................. ▍.万 事 如 意. ☆");log.warn("..................▍☆ .★ .☆ .★. ☆");log.warn("..................▍");log.warn("..▍∵ ☆ ★．．．▍▍．..．█▍ ☆ ★∵▍..");log.warn("◥█▅▅██▅▅██▅▅▅▅▅███◤");log.warn("．◥███████████████◤");log.warn("～～～～◥█████████████◤～～～～");log.warn("～～～～～～～～～～～～～～～～～～～～～～～～～");log.warn("～～～哦豁，连不上数据库，哈哈哈哈哈～～～～～～～");log.warn("～～～～～～～～～～～～～～～～～～～～～～～～～");log.warn("+jdbcDriver={}", jdbcDriver);log.warn("+jdbcUrl={}", jdbcUrl);log.warn("+jdbcUserName={}", jdbcUserName);log.warn("+jdbcUserPassword={}", jdbcUserPassword);log.warn("+testNetworkSQL={}", testNetworkSQL);log.warn("+exception class =" + e.getClass().getName());log.warn("+exception message =" + e.getMessage());log.warn("+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+");System.exit(0);}// 预定义表结构检查Set<String> prepareSqls;String urlLower = jdbcUrl.toLowerCase();if (ZYListUtils.anyMatch(MYSQL_PRODUCT_NAMES, urlLower::contains)) {prepareSqls = readSql("db_prepare_mysql");} else {prepareSqls = readSql("db_prepare_oracle");}if (prepareSqls.isEmpty()) {return;}try (Connection conn = DriverManager.getConnection(jdbcUrl, jdbcUserName, jdbcUserPassword)) {conn.setAutoCommit(true);Statement stmt = conn.createStatement();for (String prepareSql : prepareSqls) {try {stmt.executeUpdate(prepareSql);} catch (Exception e) {log.warn("execute table check sql 【{}】 false ,the column or table may exit!", prepareSql);}}} catch (Exception e) {log.warn("execute table check sql  false ,the Connection get false!");}}public Set<String> readSql(String dir) {Set<String> sqls = new HashSet<>();Resource[] resources;try {resources = new PathMatchingResourcePatternResolver().getResources("classpath*:/" + dir + "/**/*.sql");} catch (IOException e) {return sqls;}if (resources.length == 0) {return sqls;}for (Resource resource : resources) {try (InputStream inputStream = resource.getInputStream()) {String sqlText = IoUtil.read(inputStream, Charset.defaultCharset());String[] sqlArr = sqlText.split(";");for (String sql : sqlArr) {List<String> sqlItems = new ArrayList<>();StringTokenizer stringTokenizer = new StringTokenizer(sql);while (stringTokenizer.hasMoreTokens()) {String item = stringTokenizer.nextToken();sqlItems.add(item);}String finalSql = ZYStrUtils.join(sqlItems, " ");sqls.add(finalSql);}} catch (Exception e) {log.warn("sql read false");}}return sqls;}private void loadDriverClass(String jdbcDriver) {try {Class.forName(jdbcDriver);} catch (ClassNotFoundException ex) {throw new LocalException("数据库驱动文件不存在，请检查是否缺少驱动包或spring.datasource.driver-class-name配置不正确!");}}
}

spring.factories配置

org.springframework.boot.SpringApplicationRunListener =xxx.framework.mybatis.PrepareTableCheckListener