spring boot对flyway提供了丰富的配置能力，我们只需要在yaml文件添加配置信息，如下
spring:
flyway:
enabled: true
schemas: lex
默认会下载到如下的配置类
@ConfigurationProperties(prefix = "spring.flyway")
public class FlywayProperties {
/**
* 是否开启flyway，默认是开启的
*/
private boolean enabled = true;
/**
* 是否检查 migration 脚本是否存在，默认是检查的.
*/
private boolean checkLocation = true;
/**
* Locations of migrations scripts. Can contain the special "{vendor}" placeholder to
* use vendor-specific locations.
*如下，默认会在db/migration的classpath下查找migrations 文件
*/
private List<String> locations = new ArrayList<>(Collections.singletonList("classpath:db/migration"));
/**
* SQL migrations文件默认编码方式为UTF_8
*/
private Charset encoding = StandardCharsets.UTF_8;
/**
* 尝试连接数据库的最大的次数
*/
private int connectRetries;
/**
* 指定flyway执行的schemas，逗号隔离，区分大小写
*/
private List<String> schemas = new ArrayList<>();
/**
* schema history table的名字，默认为flyway_schema_history
*/
private String table = "flyway_schema_history";
/**
* Tablespace in which the schema history table is created. Ignored when using a
* database that does not support tablespaces. Defaults to the default tablespace of
* the connection used by Flyway.
*/
private String tablespace;
/**
* 当对一个已存在的schema使用baseline能力时，控制台输出的描述性
*/
private String baselineDescription = "<< Flyway Baseline >>";
/**
* 执行baseline，已存在的schema设置的版本信息，如果待添加的sql的版本信息设置的
*大于此版本信息，那么就会执行migration，否则忽略
*/
private String baselineVersion = "1";
/**
* Username recorded in the schema history table as having applied the migration.
*/
private String installedBy;
/**
* Placeholders and their replacements to apply to sql migration scripts.
*/
private Map<String, String> placeholders = new HashMap<>();
/**
* Prefix of placeholders in migration scripts.
*/
private String placeholderPrefix = "${";
/**
* Suffix of placeholders in migration scripts.
*/
private String placeholderSuffix = "}";
/**
* 是否进行占位符替换，默认是true
*/
private boolean placeholderReplacement = true;
/**
* File name prefix for SQL migrations.
*/
private String sqlMigrationPrefix = "V";
/**
* SQL migrations文件后缀名，默认是.sql
*/
private List<String> sqlMigrationSuffixes = new ArrayList<>(Collections.singleton(".sql"));
/**
* SQL migrations文件分隔符
*/
private String sqlMigrationSeparator = "__";
/**
* File name prefix for repeatable SQL migrations.
*/
private String repeatableSqlMigrationPrefix = "R";
/**
* Target version up to which migrations should be considered.
*/
private String target;
/**
* JDBC url of the database to migrate. If not set, the primary configured data source
* is used.
*/
private String url;
/**
* Login user of the database to migrate.
*/
private String user;
/**
* Login password of the database to migrate.
*/
private String password;
/**
* SQL statements to execute to initialize a connection immediately after obtaining
* it.
*/
private List<String> initSqls = new ArrayList<>();
/**
* Whether to automatically call baseline when migrating a non-empty schema.
*对一和非空的schema执行migration时是否执行baseline
*/
private boolean baselineOnMigrate;
/**
* 是否关闭clean操作，个人建议设置为true，防止意外情况出现
*/
private boolean cleanDisabled;
/**
* Whether to automatically call clean when a validation error occurs.
*/
private boolean cleanOnValidationError;
/**
*是否将所有的migration sql放在同一个事务里面执行，要看db是否支持
*/
private boolean group;
/**
* 是否忽略丢失的migretion文件，保持默认，为了文件的安全性，建议设置为false
*/
private boolean ignoreMissingMigrations;
/**
* Whether to ignore ignored migrations when reading the schema history table.
*/
private boolean ignoreIgnoredMigrations;
/**
* Whether to ignore pending migrations when reading the schema history table.
*/
private boolean ignorePendingMigrations;
/**
* Whether to ignore future migrations when reading the schema history table.
*/
private boolean ignoreFutureMigrations = true;
/**
* Whether to allow mixing transactional and non-transactional statements within the
* same migration.
*/
private boolean mixed;
/**
* 建议设置为 false，按照order来执行
*/
private boolean outOfOrder;
/**
* Whether to skip default callbacks. If true, only custom callbacks are used.
*/
private boolean skipDefaultCallbacks;
/**
* Whether to skip default resolvers. If true, only custom resolvers are used.
*/
private boolean skipDefaultResolvers;
/**
* Whether to automatically call validate when performing a migration.
*/
private boolean validateOnMigrate = true;
/**
* Whether to batch SQL statements when executing them. Requires Flyway Pro or Flyway
* Enterprise.
*/
private Boolean batch;
/**
* File to which the SQL statements of a migration dry run should be output. Requires
* Flyway Pro or Flyway Enterprise.
*/
private File dryRunOutput;
/**
* Rules for the built-in error handling to override specific SQL states and error
* codes. Requires Flyway Pro or Flyway Enterprise.
*/
private String[] errorOverrides;
/**
* Licence key for Flyway Pro or Flyway Enterprise.
*/
private String licenseKey;
/**
* Whether to enable support for Oracle SQL*Plus commands. Requires Flyway Pro or
* Flyway Enterprise.
*/
private Boolean oracleSqlplus;
/**
* Whether to issue a warning rather than an error when a not-yet-supported Oracle
* SQL*Plus statement is encountered. Requires Flyway Pro or Flyway Enterprise.
*/
private Boolean oracleSqlplusWarn;
/**
* 是否流化执行，需要flyway专业版本的支持
*/
private Boolean stream;
/**
* File name prefix for undo SQL migrations. Requires Flyway Pro or Flyway Enterprise.
*/
private String undoSqlMigrationPrefix;
}
从上可以看到，针对老的数据库，flyway也可以使用baseline的能力，对数据库做升级管理，用户可以针对各自的项目做到非常定制化的配置，如下
spring:
datasource:
username: root
password: 123456
url: jdbc:mysql://127.0.0.1:3306/lexdemo?useUnicode=true&characterEncoding=UTF-8
driver-class-name: com.mysql.jdbc.Driver
flyway:
enabled: true
schemas: lex
baseline-on-migrate: true
baseline-version: 0
clean-disabled: true
通过分析配置属性，我们可以大概看到flyway提供了callback和resolver两个扩展点，可以让我们定制化回调函数和解析器对sql进行个性化的解析。
flyway从入门到精通（七）：spring boot中flyway执行源码分析
