按照boot的通用习惯，为了引入某个组件的功能，就会在spring.factories引入这个组件的配置类，一般的这个配置类的名称就叫xxxAutoConfiguration,果不其然在spring-boot-autoconfigure 这个jar包的spring.factories文件夹下发现了这样一句
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration
示意图14.png
其中FlywayProperties不用讲，就是我们上一章讲的加载配置信息的bean
主要看下FlywayAutoConfiguration类的相关代码，如下
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(Flyway.class)
@Conditional(FlywayDataSourceCondition.class)
@ConditionalOnProperty(prefix = "spring.flyway", name = "enabled", matchIfMissing = true)
@AutoConfigureAfter({ DataSourceAutoConfiguration.class, JdbcTemplateAutoConfiguration.class,
HibernateJpaAutoConfiguration.class }) 必须DataSource,JdbcTemplate,或是HibernateJpa加载之后
@Import({ FlywayEntityManagerFactoryDependsOnPostProcessor.class, FlywayJdbcOperationsDependsOnPostProcessor.class,
FlywayNamedParameterJdbcOperationsDependencyConfiguration.class })
public class FlywayAutoConfiguration {
@Bean
//自定义的转化器，会将string或是数字转成MigrationVersion
@ConfigurationPropertiesBinding
public StringOrNumberToMigrationVersionConverter stringOrNumberMigrationVersionConverter() {
return new StringOrNumberToMigrationVersionConverter();
}
@Bean
public FlywaySchemaManagementProvider flywayDefaultDdlModeProvider(ObjectProvider<Flyway> flyways) {
return new FlywaySchemaManagementProvider(flyways);
}
@Configuration(proxyBeanMethods = false)
@ConditionalOnMissingBean(Flyway.class)
@EnableConfigurationProperties({ DataSourceProperties.class, FlywayProperties.class })
@Import({ FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor.class,
FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor.class,
FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor.class })
public static class FlywayConfiguration {
@Bean
public Flyway flyway(FlywayProperties properties, DataSourceProperties dataSourceProperties,
ResourceLoader resourceLoader, ObjectProvider<DataSource> dataSource,
@FlywayDataSource ObjectProvider<DataSource> flywayDataSource,
ObjectProvider<FlywayConfigurationCustomizer> fluentConfigurationCustomizers,
ObjectProvider<JavaMigration> javaMigrations, ObjectProvider<Callback> callbacks) {
FluentConfiguration configuration = new FluentConfiguration(resourceLoader.getClassLoader());
//如果Flyway配置了DataSource信息，就使用，不然使用配置的项目的DataSource信息
DataSource dataSourceToMigrate = configureDataSource(configuration, properties, dataSourceProperties,
flywayDataSource.getIfAvailable(), dataSource.getIfUnique());
checkLocationExists(dataSourceToMigrate, properties, resourceLoader);
//将properties赋值到configuration
configureProperties(configuration, properties);
List<Callback> orderedCallbacks = callbacks.orderedStream().collect(Collectors.toList());
//注册callbacks
configureCallbacks(configuration, orderedCallbacks);
fluentConfigurationCustomizers.orderedStream().forEach((customizer) -> customizer.customize(configuration));
configureFlywayCallbacks(configuration, orderedCallbacks);
List<JavaMigration> migrations = javaMigrations.stream().collect(Collectors.toList());
//注册JavaMigration，我们基本都是用的sql的写法，这个可以忽略
configureJavaMigrations(configuration, migrations);
return configuration.load();
}
private DataSource configureDataSource(FluentConfiguration configuration, FlywayProperties properties,
DataSourceProperties dataSourceProperties, DataSource flywayDataSource, DataSource dataSource) {
if (properties.isCreateDataSource()) {
String url = getProperty(properties::getUrl, dataSourceProperties::determineUrl);
String user = getProperty(properties::getUser, dataSourceProperties::determineUsername);
String password = getProperty(properties::getPassword, dataSourceProperties::determinePassword);
configuration.dataSource(url, user, password);
if (!CollectionUtils.isEmpty(properties.getInitSqls())) {
String initSql = StringUtils.collectionToDelimitedString(properties.getInitSqls(), "\n");
configuration.initSql(initSql);
}
}
else if (flywayDataSource != null) {
configuration.dataSource(flywayDataSource);
}
else {
configuration.dataSource(dataSource);
}
return configuration.getDataSource();
}
private void checkLocationExists(DataSource dataSource, FlywayProperties properties,
ResourceLoader resourceLoader) {
if (properties.isCheckLocation()) {
List<String> locations = new LocationResolver(dataSource).resolveLocations(properties.getLocations());
if (!hasAtLeastOneLocation(resourceLoader, locations)) {
throw new FlywayMigrationScriptMissingException(locations);
}
}
}
private void configureProperties(FluentConfiguration configuration, FlywayProperties properties) {
PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
String[] locations = new LocationResolver(configuration.getDataSource())
.resolveLocations(properties.getLocations()).toArray(new String[0]);
map.from(locations).to(configuration::locations);
map.from(properties.getEncoding()).to(configuration::encoding);
map.from(properties.getConnectRetries()).to(configuration::connectRetries);
map.from(properties.getSchemas()).as(StringUtils::toStringArray).to(configuration::schemas);
map.from(properties.getTable()).to(configuration::table);
// No method reference for compatibility with Flyway 5.x
map.from(properties.getTablespace()).whenNonNull().to((tablespace) -> configuration.tablespace(tablespace));
map.from(properties.getBaselineDescription()).to(configuration::baselineDescription);
map.from(properties.getBaselineVersion()).to(configuration::baselineVersion);
map.from(properties.getInstalledBy()).to(configuration::installedBy);
map.from(properties.getPlaceholders()).to(configuration::placeholders);
map.from(properties.getPlaceholderPrefix()).to(configuration::placeholderPrefix);
map.from(properties.getPlaceholderSuffix()).to(configuration::placeholderSuffix);
map.from(properties.isPlaceholderReplacement()).to(configuration::placeholderReplacement);
map.from(properties.getSqlMigrationPrefix()).to(configuration::sqlMigrationPrefix);
map.from(properties.getSqlMigrationSuffixes()).as(StringUtils::toStringArray)
.to(configuration::sqlMigrationSuffixes);
map.from(properties.getSqlMigrationSeparator()).to(configuration::sqlMigrationSeparator);
map.from(properties.getRepeatableSqlMigrationPrefix()).to(configuration::repeatableSqlMigrationPrefix);
map.from(properties.getTarget()).to(configuration::target);
map.from(properties.isBaselineOnMigrate()).to(configuration::baselineOnMigrate);
map.from(properties.isCleanDisabled()).to(configuration::cleanDisabled);
map.from(properties.isCleanOnValidationError()).to(configuration::cleanOnValidationError);
map.from(properties.isGroup()).to(configuration::group);
map.from(properties.isIgnoreMissingMigrations()).to(configuration::ignoreMissingMigrations);
map.from(properties.isIgnoreIgnoredMigrations()).to(configuration::ignoreIgnoredMigrations);
map.from(properties.isIgnorePendingMigrations()).to(configuration::ignorePendingMigrations);
map.from(properties.isIgnoreFutureMigrations()).to(configuration::ignoreFutureMigrations);
map.from(properties.isMixed()).to(configuration::mixed);
map.from(properties.isOutOfOrder()).to(configuration::outOfOrder);
map.from(properties.isSkipDefaultCallbacks()).to(configuration::skipDefaultCallbacks);
map.from(properties.isSkipDefaultResolvers()).to(configuration::skipDefaultResolvers);
map.from(properties.isValidateOnMigrate()).to(configuration::validateOnMigrate);
// Pro properties
map.from(properties.getBatch()).whenNonNull().to(configuration::batch);
map.from(properties.getDryRunOutput()).whenNonNull().to(configuration::dryRunOutput);
map.from(properties.getErrorOverrides()).whenNonNull().to(configuration::errorOverrides);
map.from(properties.getLicenseKey()).whenNonNull().to(configuration::licenseKey);
map.from(properties.getOracleSqlplus()).whenNonNull().to(configuration::oracleSqlplus);
// No method reference for compatibility with Flyway 5.x
map.from(properties.getOracleSqlplusWarn()).whenNonNull()
.to((oracleSqlplusWarn) -> configuration.oracleSqlplusWarn(oracleSqlplusWarn));
map.from(properties.getStream()).whenNonNull().to(configuration::stream);
map.from(properties.getUndoSqlMigrationPrefix()).whenNonNull().to(configuration::undoSqlMigrationPrefix);
}
private void configureCallbacks(FluentConfiguration configuration, List<Callback> callbacks) {
if (!callbacks.isEmpty()) {
configuration.callbacks(callbacks.toArray(new Callback[0]));
}
}
private void configureFlywayCallbacks(FluentConfiguration flyway, List<Callback> callbacks) {
if (!callbacks.isEmpty()) {
flyway.callbacks(callbacks.toArray(new Callback[0]));
}
}
private void configureJavaMigrations(FluentConfiguration flyway, List<JavaMigration> migrations) {
if (!migrations.isEmpty()) {
try {
flyway.javaMigrations(migrations.toArray(new JavaMigration[0]));
}
catch (NoSuchMethodError ex) {
// Flyway 5.x
}
}
}
private String getProperty(Supplier<String> property, Supplier<String> defaultValue) {
String value = property.get();
return (value != null) ? value : defaultValue.get();
}
private boolean hasAtLeastOneLocation(ResourceLoader resourceLoader, Collection<String> locations) {
for (String location : locations) {
if (resourceLoader.getResource(normalizePrefix(location)).exists()) {
return true;
}
}
return false;
}
private String normalizePrefix(String location) {
return location.replace("filesystem:", "file:");
}
//这个bean很重要，会在下一章讲到
@Bean
@ConditionalOnMissingBean
public FlywayMigrationInitializer flywayInitializer(Flyway flyway,
ObjectProvider<FlywayMigrationStrategy> migrationStrategy) {
return new FlywayMigrationInitializer(flyway, migrationStrategy.getIfAvailable());
}
}
/**
* Post processor to ensure that {@link EntityManagerFactory} beans depend on any
* {@link FlywayMigrationInitializer} beans.
*/
@ConditionalOnClass(LocalContainerEntityManagerFactoryBean.class)
@ConditionalOnBean(AbstractEntityManagerFactoryBean.class)
static class FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor
extends EntityManagerFactoryDependsOnPostProcessor {
FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor() {
super(FlywayMigrationInitializer.class);
}
}
/**
*此BeanFactoryPostProcessor保证了JdbcOperations depends on
*FlywayMigrationInitializer，如下的两个也是这个意思，保证了在对db做任何的操作前
*先会完成Flyway的migrate操作
* Post processor to ensure that {@link JdbcOperations} beans depend on any
* {@link FlywayMigrationInitializer} beans.
*/
@ConditionalOnClass(JdbcOperations.class)
@ConditionalOnBean(JdbcOperations.class)
static class FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor
extends JdbcOperationsDependsOnPostProcessor {
FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor() {
super(FlywayMigrationInitializer.class);
}
}
/**
* Post processor to ensure that {@link NamedParameterJdbcOperations} beans
*depend on
* any {@link FlywayMigrationInitializer} beans.
*/
@ConditionalOnClass(NamedParameterJdbcOperations.class)
@ConditionalOnBean(NamedParameterJdbcOperations.class)
static class FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor
extends NamedParameterJdbcOperationsDependsOnPostProcessor {
FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor() {
super(FlywayMigrationInitializer.class);
}
}
/**
* Post processor to ensure that {@link EntityManagerFactory} beans depend on any
* {@link Flyway} beans.
*/
@ConditionalOnClass(LocalContainerEntityManagerFactoryBean.class)
@ConditionalOnBean(AbstractEntityManagerFactoryBean.class)
static class FlywayEntityManagerFactoryDependsOnPostProcessor extends EntityManagerFactoryDependsOnPostProcessor {
FlywayEntityManagerFactoryDependsOnPostProcessor() {
super(Flyway.class);
}
}
/**
* Post processor to ensure that {@link JdbcOperations} beans depend on any
* {@link Flyway} beans.
*/
@ConditionalOnClass(JdbcOperations.class)
@ConditionalOnBean(JdbcOperations.class)
static class FlywayJdbcOperationsDependsOnPostProcessor extends JdbcOperationsDependsOnPostProcessor {
FlywayJdbcOperationsDependsOnPostProcessor() {
super(Flyway.class);
}
}
/**
* Post processor to ensure that {@link NamedParameterJdbcOperations} beans depend on
* any {@link Flyway} beans.
*/
@ConditionalOnClass(NamedParameterJdbcOperations.class)
@ConditionalOnBean(NamedParameterJdbcOperations.class)
protected static class FlywayNamedParameterJdbcOperationsDependencyConfiguration
extends NamedParameterJdbcOperationsDependsOnPostProcessor {
public FlywayNamedParameterJdbcOperationsDependencyConfiguration() {
super(Flyway.class);
}
}
private static class LocationResolver {
private static final String VENDOR_PLACEHOLDER = "{vendor}";
private final DataSource dataSource;
LocationResolver(DataSource dataSource) {
this.dataSource = dataSource;
}
List<String> resolveLocations(List<String> locations) {
if (usesVendorLocation(locations)) {
DatabaseDriver databaseDriver = getDatabaseDriver();
return replaceVendorLocations(locations, databaseDriver);
}
return locations;
}
private List<String> replaceVendorLocations(List<String> locations, DatabaseDriver databaseDriver) {
if (databaseDriver == DatabaseDriver.UNKNOWN) {
return locations;
}
String vendor = databaseDriver.getId();
return locations.stream().map((location) -> location.replace(VENDOR_PLACEHOLDER, vendor))
.collect(Collectors.toList());
}
private DatabaseDriver getDatabaseDriver() {
try {
String url = JdbcUtils.extractDatabaseMetaData(this.dataSource, "getURL");
return DatabaseDriver.fromJdbcUrl(url);
}
catch (MetaDataAccessException ex) {
throw new IllegalStateException(ex);
}
}
private boolean usesVendorLocation(Collection<String> locations) {
for (String location : locations) {
if (location.contains(VENDOR_PLACEHOLDER)) {
return true;
}
}
return false;
}
}
/**
* Convert a String or Number to a {@link MigrationVersion}.
*/
private static class StringOrNumberToMigrationVersionConverter implements GenericConverter {
private static final Set<ConvertiblePair> CONVERTIBLE_TYPES;
static {
Set<ConvertiblePair> types = new HashSet<>(2);
types.add(new ConvertiblePair(String.class, MigrationVersion.class));
types.add(new ConvertiblePair(Number.class, MigrationVersion.class));
CONVERTIBLE_TYPES = Collections.unmodifiableSet(types);
}
@Override
public Set<ConvertiblePair> getConvertibleTypes() {
return CONVERTIBLE_TYPES;
}
@Override
public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
String value = ObjectUtils.nullSafeToString(source);
return MigrationVersion.fromVersion(value);
}
}
static final class FlywayDataSourceCondition extends AnyNestedCondition {
FlywayDataSourceCondition() {
super(ConfigurationPhase.REGISTER_BEAN);
}
@ConditionalOnBean(DataSource.class)
private static final class DataSourceBeanCondition {
}
@ConditionalOnProperty(prefix = "spring.flyway", name = "url", matchIfMissing = false)
private static final class FlywayUrlCondition {
}
}
}
上面这个configuration主要就是创建了一个叫flyway的bean，并在创建的过程中对配置属性做了check和相关的callback的注册
flyway从入门到精通（八）：spring boot中flyway执行源码分析
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