快速入门
依赖引入
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>dynamic-datasource-spring-boot-starter</artifactId>
<version>3.5.1</version>
</dependency>
配置文件
spring.datasource.druid.stat-view-servlet.enabled = true
spring.datasource.druid.stat-view-servlet.login-username = root
spring.datasource.druid.stat-view-servlet.login-password = root
spring.datasource.dynamic.druid.filters = stat,wall
spring.datasource.druid.aop-patterns = com.charles.mapper.*
spring.datasource.druid.web-stat-filter.enabled = true
spring.datasource.druid.filter.stat.enabled = true
spring.datasource.druid.filter.stat.log-slow-sql = true
spring.datasource.druid.filter.stat.slow-sql-millis = 1000
spring.datasource.dynamic.primary = db0
spring.datasource.dynamic.datasource.db1.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.dynamic.datasource.db1.url = jdbc:mysql://127.0.0.1:3306/eb-crm?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true
spring.datasource.dynamic.datasource.db1.username = app
spring.datasource.dynamic.datasource.db1.password = Ys@123456
spring.datasource.dynamic.datasource.db1.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.dynamic.datasource.db0.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.dynamic.datasource.db0.url = jdbc:mysql://127.0.0.1:3306/newcrm?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true
spring.datasource.dynamic.datasource.db0.username = app
spring.datasource.dynamic.datasource.db0.password = Ys@123456
spring.datasource.dynamic.datasource.db0.type = com.alibaba.druid.pool.DruidDataSource
使用注解拦截
@DS("db1")
public interface TbpExcelLogMapper extends BaseMapper<TbpExcelLog> {
}
源码解析
启动的时候，会加载在dynamic-datasource-spring-boot-starter的jar包中的spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.baomidou.dynamic.datasource.spring.boot.autoconfigure.DynamicDataSourceAutoConfiguration
数据源加载
在DynamicDataSourceAutoConfiguration会注入DynamicRoutingDataSource
@Bean
@ConditionalOnMissingBean
public DataSource dataSource() {
DynamicRoutingDataSource dataSource = new DynamicRoutingDataSource();
dataSource.setPrimary(properties.getPrimary());
dataSource.setStrict(properties.getStrict());
dataSource.setStrategy(properties.getStrategy());
dataSource.setP6spy(properties.getP6spy());
dataSource.setSeata(properties.getSeata());
return dataSource;
}
DynamicRoutingDataSource#afterPropertiesSet，系统启动的时候会加载所有的数据源
@Override
public void afterPropertiesSet() throws Exception {
// 检查开启了配置但没有相关依赖
checkEnv();
// 添加并分组数据源
Map<String, DataSource> dataSources = new HashMap<>(16);
for (DynamicDataSourceProvider provider : providers) {
dataSources.putAll(provider.loadDataSources());
}
for (Map.Entry<String, DataSource> dsItem : dataSources.entrySet()) {
addDataSource(dsItem.getKey(), dsItem.getValue());
}
// 检测默认数据源是否设置
if (groupDataSources.containsKey(primary)) {
log.info("dynamic-datasource initial loaded [{}] datasource,primary group datasource named [{}]", dataSources.size(), primary);
} else if (dataSourceMap.containsKey(primary)) {
log.info("dynamic-datasource initial loaded [{}] datasource,primary datasource named [{}]", dataSources.size(), primary);
} else {
log.warn("dynamic-datasource initial loaded [{}] datasource,Please add your primary datasource or check your configuration", dataSources.size());
}
}
在DynamicDataSourceAutoConfiguration会注入DynamicDataSourceProvider
@Bean
public DynamicDataSourceProvider ymlDynamicDataSourceProvider() {
return new YmlDynamicDataSourceProvider(properties.getDatasource());
}
AbstractDataSourceProvider#createDataSourceMap，根据配置文件中的信息创建数据源。
protected Map<String, DataSource> createDataSourceMap(
Map<String, DataSourceProperty> dataSourcePropertiesMap) {
Map<String, DataSource> dataSourceMap = new HashMap<>(dataSourcePropertiesMap.size() * 2);
for (Map.Entry<String, DataSourceProperty> item : dataSourcePropertiesMap.entrySet()) {
String dsName = item.getKey();
DataSourceProperty dataSourceProperty = item.getValue();
String poolName = dataSourceProperty.getPoolName();
if (poolName == null || "".equals(poolName)) {
poolName = dsName;
}
dataSourceProperty.setPoolName(poolName);
dataSourceMap.put(dsName, defaultDataSourceCreator.createDataSource(dataSourceProperty));
}
return dataSourceMap;
}
AbstractDataSourceCreator#createDataSource，模板方法。该方法会调用dataSourceInitEvent.beforeCreate(dataSourceProperty);。而doCreateDataSource交由每个子类来创建。
@Override
public DataSource createDataSource(DataSourceProperty dataSourceProperty) {
String publicKey = dataSourceProperty.getPublicKey();
if (StringUtils.isEmpty(publicKey)) {
publicKey = properties.getPublicKey();
dataSourceProperty.setPublicKey(publicKey);
}
Boolean lazy = dataSourceProperty.getLazy();
if (lazy == null) {
lazy = properties.getLazy();
dataSourceProperty.setLazy(lazy);
}
dataSourceInitEvent.beforeCreate(dataSourceProperty);
DataSource dataSource = doCreateDataSource(dataSourceProperty);
dataSourceInitEvent.afterCreate(dataSource);
this.runScrip(dataSource, dataSourceProperty);
return wrapDataSource(dataSource, dataSourceProperty);
}
DruidDataSourceCreator#doCreateDataSource，创建druid数据源。根据全局配置gConfig和定制化配置结合来生成DruidDataSource。spring.datasource.dynamic.datasource.xxx.type=com.alibaba.druid.pool.DruidDataSource可以进行定制化配置，也可以通过spring.datasource.dynamic.druid全局配置druid的属性
private DruidConfig gConfig;
@Override
public DataSource doCreateDataSource(DataSourceProperty dataSourceProperty) {
DruidDataSource dataSource = new DruidDataSource();
dataSource.setUsername(dataSourceProperty.getUsername());
dataSource.setPassword(dataSourceProperty.getPassword());
dataSource.setUrl(dataSourceProperty.getUrl());
dataSource.setName(dataSourceProperty.getPoolName());
String driverClassName = dataSourceProperty.getDriverClassName();
if (!StringUtils.isEmpty(driverClassName)) {
dataSource.setDriverClassName(driverClassName);
}
DruidConfig config = dataSourceProperty.getDruid();
Properties properties = config.toProperties(gConfig);
List<Filter> proxyFilters = this.initFilters(dataSourceProperty, properties.getProperty("druid.filters"));
dataSource.setProxyFilters(proxyFilters);
dataSource.configFromPropety(properties);
//连接参数单独设置
dataSource.setConnectProperties(config.getConnectionProperties());
//设置druid内置properties不支持的的参数
this.setParam(dataSource, config);
if (Boolean.FALSE.equals(dataSourceProperty.getLazy())) {
try {
dataSource.init();
} catch (SQLException e) {
throw new ErrorCreateDataSourceException("druid create error", e);
}
}
return dataSource;
}
切面修改数据源的key
在DynamicDataSourceAutoConfiguration会注入DynamicDataSourceAnnotationAdvisor
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
@Bean
@ConditionalOnProperty(prefix = DynamicDataSourceProperties.PREFIX + ".aop", name = "enabled", havingValue = "true", matchIfMissing = true)
public Advisor dynamicDatasourceAnnotationAdvisor(DsProcessor dsProcessor) {
DynamicDatasourceAopProperties aopProperties = properties.getAop();
DynamicDataSourceAnnotationInterceptor interceptor = new DynamicDataSourceAnnotationInterceptor(aopProperties.getAllowedPublicOnly(), dsProcessor);
DynamicDataSourceAnnotationAdvisor advisor = new DynamicDataSourceAnnotationAdvisor(interceptor, DS.class);
advisor.setOrder(aopProperties.getOrder());
return advisor;
}
DynamicDataSourceAnnotationAdvisor#buildPointcut，构造切面，对方法和类都拦截。
private Pointcut buildPointcut() {
Pointcut cpc = new AnnotationMatchingPointcut(annotation, true);
Pointcut mpc = new AnnotationMethodPoint(annotation);
return new ComposablePointcut(cpc).union(mpc);
}
如果使用@Aspect来切面的话，对注解进行切片，要注意@within和@annotation的区别。
1. @within 对象级别
2. @annotation 方法级别
DynamicDataSourceAnnotationInterceptor#invoke，获取方法上或者类上的注解中的key
@Override
public Object invoke(MethodInvocation invocation) throws Throwable {
String dsKey = determineDatasourceKey(invocation);
DynamicDataSourceContextHolder.push(dsKey);
try {
return invocation.proceed();
} finally {
DynamicDataSourceContextHolder.poll();
}
}
DynamicDataSourceAnnotationInterceptor#determineDatasourceKey，如果key以#开头，则返回dsProcessor.determineDatasource(invocation, key)，否则直接返回key。
private String determineDatasourceKey(MethodInvocation invocation) {
String key = dataSourceClassResolver.findKey(invocation.getMethod(), invocation.getThis());
return key.startsWith(DYNAMIC_PREFIX) ? dsProcessor.determineDatasource(invocation, key) : key;
}
DsProcessor
在DynamicDataSourceAutoConfiguration会注入DsProcessor，使用过滤器链的模式进行处理。
@Bean
@ConditionalOnMissingBean
public DsProcessor dsProcessor(BeanFactory beanFactory) {
DsHeaderProcessor headerProcessor = new DsHeaderProcessor();
DsSessionProcessor sessionProcessor = new DsSessionProcessor();
DsSpelExpressionProcessor spelExpressionProcessor = new DsSpelExpressionProcessor();
spelExpressionProcessor.setBeanResolver(new BeanFactoryResolver(beanFactory));
headerProcessor.setNextProcessor(sessionProcessor);
sessionProcessor.setNextProcessor(spelExpressionProcessor);
return headerProcessor;
}
DsHeaderProcessor#doDetermineDatasource，如果方法上的注解类似于@DS(#header=tenat_id)，那么切换路由的key是由header中tenat_id的值决定的。
@Override
public String doDetermineDatasource(MethodInvocation invocation, String key) {
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
return request.getHeader(key.substring(8));
}
spelExpressionProcessor是支持表达式的。
在注解中配置@DS("#header=tenantName")，则从header里面去寻找key；写了@DS("#session=tenantName")，就从session里面获取以tenantName为键的值。而@DS("#tenantName")和@DS("#user.tenantName")根据参数来获取。
获取数据源
获取连接，AbstractRoutingDataSource#getConnection()。首先获取数据源，从数据源中获取Connection
@Override
public Connection getConnection() throws SQLException {
String xid = TransactionContext.getXID();
if (StringUtils.isEmpty(xid)) {
return determineDataSource().getConnection();
} else {
String ds = DynamicDataSourceContextHolder.peek();
ds = StringUtils.isEmpty(ds) ? "default" : ds;
ConnectionProxy connection = ConnectionFactory.getConnection(ds);
return connection == null ? getConnectionProxy(ds, determineDataSource().getConnection()) : connection;
}
}
DynamicRoutingDataSource#determineDataSource，获取线程变量的数据，根据线程变量获取数据源。
@Override
public DataSource determineDataSource() {
String dsKey = DynamicDataSourceContextHolder.peek();
return getDataSource(dsKey);
}
DynamicRoutingDataSource#getDataSource，该key为空，获取默认数据源，优先从groupDataSources里面获取数据源，然后再从dataSourceMap里面获取。
public DataSource getDataSource(String ds) {
if (StringUtils.isEmpty(ds)) {
return determinePrimaryDataSource();
} else if (!groupDataSources.isEmpty() && groupDataSources.containsKey(ds)) {
log.debug("dynamic-datasource switch to the datasource named [{}]", ds);
return groupDataSources.get(ds).determineDataSource();
} else if (dataSourceMap.containsKey(ds)) {
log.debug("dynamic-datasource switch to the datasource named [{}]", ds);
return dataSourceMap.get(ds);
}
if (strict) {
throw new CannotFindDataSourceException("dynamic-datasource could not find a datasource named" + ds);
}
return determinePrimaryDataSource();
}
DynamicDataSourceStrategy，从群组里面获取数据源需要配置获取策略，从集合中决定是哪一个，有随机和轮询。
public class RandomDynamicDataSourceStrategy implements DynamicDataSourceStrategy {
@Override
public String determineKey(List<String> dsNames) {
return dsNames.get(ThreadLocalRandom.current().nextInt(dsNames.size()));
}
}
比对一下，spring-jdbc中的动态数据源切换。
AbstractRoutingDataSource#afterPropertiesSet，重写了InitializingBean#afterPropertiesSet的方法。
public void afterPropertiesSet() {
if (this.targetDataSources == null) {
throw new IllegalArgumentException("Property 'targetDataSources' is required");
} else {
this.resolvedDataSources = new HashMap(this.targetDataSources.size());
this.targetDataSources.forEach((key, value) -> {
Object lookupKey = this.resolveSpecifiedLookupKey(key);
DataSource dataSource = this.resolveSpecifiedDataSource(value);
this.resolvedDataSources.put(lookupKey, dataSource);
});
if (this.defaultTargetDataSource != null) {
this.resolvedDefaultDataSource = this.resolveSpecifiedDataSource(this.defaultTargetDataSource);
}
}
}
AbstractRoutingDataSource#getConnection()。获取lookupKey的方式由子类决定。
public Connection getConnection() throws SQLException {
return this.determineTargetDataSource().getConnection();
}
protected DataSource determineTargetDataSource() {
Assert.notNull(this.resolvedDataSources, "DataSource router not initialized");
Object lookupKey = this.determineCurrentLookupKey();
DataSource dataSource = (DataSource)this.resolvedDataSources.get(lookupKey);
if (dataSource == null && (this.lenientFallback || lookupKey == null)) {
dataSource = this.resolvedDefaultDataSource;
}
if (dataSource == null) {
throw new IllegalStateException("Cannot determine target DataSource for lookup key [" + lookupKey + "]");
} else {
return dataSource;
}
}
@Nullable
protected abstract Object determineCurrentLookupKey();
多数据源事务
在DynamicDataSourceAutoConfiguration会注入dynamicTransactionAdvisor，主要是拦截处理有DSTransactional注解的方法。
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
@Bean
@ConditionalOnProperty(prefix = DynamicDataSourceProperties.PREFIX, name = "seata", havingValue = "false", matchIfMissing = true)
public Advisor dynamicTransactionAdvisor() {
DynamicLocalTransactionInterceptor interceptor = new DynamicLocalTransactionInterceptor();
return new DynamicDataSourceAnnotationAdvisor(interceptor, DSTransactional.class);
}
DynamicLocalTransactionInterceptor，开启事务。
public class DynamicLocalTransactionInterceptor implements MethodInterceptor {
@Override
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
if (!StringUtils.isEmpty(TransactionContext.getXID())) {
return methodInvocation.proceed();
}
boolean state = true;
Object o;
LocalTxUtil.startTransaction();
try {
o = methodInvocation.proceed();
} catch (Exception e) {
state = false;
throw e;
} finally {
if (state) {
LocalTxUtil.commit();
} else {
LocalTxUtil.rollback();
}
}
return o;
}
}
LocalTxUtil#startTransaction
public static void startTransaction() {
if (!StringUtils.isEmpty(TransactionContext.getXID())) {
log.debug("dynamic-datasource exist local tx [{}]", TransactionContext.getXID());
} else {
String xid = UUID.randomUUID().toString();
TransactionContext.bind(xid);
log.debug("dynamic-datasource start local tx [{}]", xid);
}
}
AbstractRoutingDataSource#getConnection()，判断是否存在事务id，如果存在，则获取连接，并封装成ConnectionProxy。
@Override
public Connection getConnection() throws SQLException {
String xid = TransactionContext.getXID();
if (StringUtils.isEmpty(xid)) {
return determineDataSource().getConnection();
} else {
String ds = DynamicDataSourceContextHolder.peek();
ds = StringUtils.isEmpty(ds) ? "default" : ds;
ConnectionProxy connection = ConnectionFactory.getConnection(ds);
return connection == null ? getConnectionProxy(ds, determineDataSource().getConnection()) : connection;
}
}
private Connection getConnectionProxy(String ds, Connection connection) {
ConnectionProxy connectionProxy = new ConnectionProxy(connection, ds);
ConnectionFactory.putConnection(ds, connectionProxy);
return connectionProxy;
}
ConnectionFactory#putConnection，存储到线程变量中的concurrentHashMap。
public static void putConnection(String ds, ConnectionProxy connection) {
Map<String, ConnectionProxy> concurrentHashMap = CONNECTION_HOLDER.get();
if (!concurrentHashMap.containsKey(ds)) {
try {
connection.setAutoCommit(false);
} catch (SQLException e) {
e.printStackTrace();
}
concurrentHashMap.put(ds, connection);
}
}
提交事务，LocalTxUtil#commit
public static void commit() {
ConnectionFactory.notify(true);
log.debug("dynamic-datasource commit local tx [{}]", TransactionContext.getXID());
TransactionContext.remove();
}
ConnectionFactory#notify，对于线程变量中的连接全部处理（回滚或者提交），并清空线程变量。
public static void notify(Boolean state) {
try {
Map<String, ConnectionProxy> concurrentHashMap = CONNECTION_HOLDER.get();
for (ConnectionProxy connectionProxy : concurrentHashMap.values()) {
connectionProxy.notify(state);
}
} finally {
CONNECTION_HOLDER.remove();
}
}
配置文件加密
在DynamicDataSourceAutoConfiguration会注入EncDataSourceInitEvent
@Bean
@ConditionalOnMissingBean
public DataSourceInitEvent dataSourceInitEvent() {
return new EncDataSourceInitEvent();
}
EncDataSourceInitEvent#beforeCreate，对加密的字符串进行解密
@Override
public void beforeCreate(DataSourceProperty dataSourceProperty) {
String publicKey = dataSourceProperty.getPublicKey();
if (StringUtils.hasText(publicKey)) {
dataSourceProperty.setUrl(decrypt(publicKey, dataSourceProperty.getUrl()));
dataSourceProperty.setUsername(decrypt(publicKey, dataSourceProperty.getUsername()));
dataSourceProperty.setPassword(decrypt(publicKey, dataSourceProperty.getPassword()));
}
}
EncDataSourceInitEvent#decrypt，匹配正则表达式则进行解密。 Pattern ENC_PATTERN = Pattern.compile("^ENC\\((.*)\\)$");
private String decrypt(String publicKey, String cipherText) {
if (StringUtils.hasText(cipherText)) {
Matcher matcher = ENC_PATTERN.matcher(cipherText);
if (matcher.find()) {
try {
return CryptoUtils.decrypt(publicKey, matcher.group(1));
} catch (Exception e) {
log.error("DynamicDataSourceProperties.decrypt error ", e);
}
}
}
return cipherText;
}
脚本执行器
AbstractDataSourceCreator#runScrip，用对应的数据源执行脚本
private void runScrip(DataSource dataSource, DataSourceProperty dataSourceProperty) {
DatasourceInitProperties initProperty = dataSourceProperty.getInit();
String schema = initProperty.getSchema();
String data = initProperty.getData();
if (StringUtils.hasText(schema) || StringUtils.hasText(data)) {
ScriptRunner scriptRunner = new ScriptRunner(initProperty.isContinueOnError(), initProperty.getSeparator());
if (StringUtils.hasText(schema)) {
scriptRunner.runScript(dataSource, schema);
}
if (StringUtils.hasText(data)) {
scriptRunner.runScript(dataSource, data);
}
}
}
主从插件
MasterSlaveAutoRoutingPlugin。当进行查询的时候，切换数据源SLAVE；当进行更新的时候，切换数据源，MASTER。文章来源：https://www.toymoban.com/news/detail-420270.html
@Intercepts({
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class}),
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})})
@Slf4j
public class MasterSlaveAutoRoutingPlugin implements Interceptor {
@Autowired
protected DataSource dynamicDataSource;
@Override
public Object intercept(Invocation invocation) throws Throwable {
Object[] args = invocation.getArgs();
MappedStatement ms = (MappedStatement) args[0];
String pushedDataSource = null;
try {
String dataSource = SqlCommandType.SELECT == ms.getSqlCommandType() ? DdConstants.SLAVE : DdConstants.MASTER;
pushedDataSource = DynamicDataSourceContextHolder.push(dataSource);
return invocation.proceed();
} finally {
if (pushedDataSource != null) {
DynamicDataSourceContextHolder.poll();
}
}
}
@Override
public Object plugin(Object target) {
return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties properties) {
}
}
文章来源地址https://www.toymoban.com/news/detail-420270.html
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