Mybatis+Spring实现Mysql读写分离
2024-10-08 00:34:32
使用spring AbstractRoutingDatasource实现多数据源
public class DynamicDataSource extends AbstractRoutingDataSource {
//写数据源
private Object writeDataSource;
//读数据源
private Object readDataSource; @Override
public void afterPropertiesSet() {
Assert.isNull(writeDataSource, "Property 'writeDataSource' is required");
setDefaultTargetDataSource(writeDataSource);
Map<Object, Object> targetDataSources = new HashMap<Object, Object>();
targetDataSources.put(DBTypeEnum.WRITE.name(), writeDataSource);
if (null != readDataSource)
targetDataSources.put(DBTypeEnum.READ.name(), readDataSource);
setTargetDataSources(targetDataSources);
super.afterPropertiesSet();
}
/**
* 获取当前使用那个数据源
*/
@Override
protected Object determineCurrentLookupKey() {
DBTypeEnum dataSource = DbContextHolder.getDbType();
if (null == dataSource || dataSource == DBTypeEnum.WRITE)
return DBTypeEnum.WRITE.name();
return DBTypeEnum.READ.name();
}
public Object getWriteDataSource() {
return writeDataSource;
}
public void setWriteDataSource(Object writeDataSource) {
this.writeDataSource = writeDataSource;
}
public Object getReadDataSource() {
return readDataSource;
}
public void setReadDataSource(Object readDataSource) {
this.readDataSource = readDataSource;
}
}
读写数据库类型
public enum DBTypeEnum {
WRITE, READ;
}
当前数据库配置上下文
public class DbContextHolder {
private static final ThreadLocal<DBTypeEnum> DATASOURCES = new ThreadLocal<DBTypeEnum>();
private DbContextHolder() {
}
/**
* 设置数据源
*
* @param dbType
*/
public static void setDbType(DBTypeEnum dbType) {
DATASOURCES.set(dbType.WRITE);
}
/*
* 获取当前数据源
* @return DBTypeEnum
* */
public static DBTypeEnum getDbType() {
return DATASOURCES.get();
}
/**
* 清除上下文数据
*/
public static void clearDbType() {
DATASOURCES.remove();
}
}
自定义事务管理器
public class DynamicDataSourceTransactionManager extends DataSourceTransactionManager {
/**
* 设置数据源
*/
@Override
protected void doBegin(Object transaction, TransactionDefinition definition) {
boolean readOnly = definition.isReadOnly();
if (readOnly)
DbContextHolder.setDbType(DBTypeEnum.READ);
DbContextHolder.setDbType(DBTypeEnum.WRITE);
super.doBegin(transaction, definition);
}
/**
* 清理本地线程数据源
*/
@Override
protected void doCleanupAfterCompletion(Object transaction) {
super.doCleanupAfterCompletion(transaction);
DbContextHolder.clearDbType();
}
}
mybatis插件(拦截器)
@Intercepts({
@Signature(type = Executor.class, method = "update", args = {
MappedStatement.class, Object.class}),
@Signature(type = Executor.class, method = "query", args = {
MappedStatement.class, Object.class, RowBounds.class,
ResultHandler.class})})
public class DynamicPlugin implements Interceptor {
private static final Logger _log = LoggerFactory.getLogger(DynamicPlugin.class);
private static final String REGEX = ".*insert\\u0020.*|.*delete\\u0020.*|.*update\\u0020.*";
private static final Map<String, DBTypeEnum> cachaMap = new HashMap<String, DBTypeEnum>();
@Override
public Object intercept(Invocation invocation) throws Throwable {
boolean isSynchronizationActive = TransactionSynchronizationManager.isSynchronizationActive();
if (!isSynchronizationActive) {
MappedStatement ms = (MappedStatement) invocation.getArgs()[0];
DBTypeEnum dbTypeEnum = null;
if ((dbTypeEnum = cachaMap.get(ms.getId())) == null) {
//读方法
if (ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
//!selectKeu为自增id查询主键(SELECT LAST_INSERT_ID)方法，使用主库
if (ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX))
dbTypeEnum = DBTypeEnum.WRITE;
else {
BoundSql boundSql = ms.getSqlSource().getBoundSql(invocation.getArgs()[1]);
String sql = boundSql.getSql().toLowerCase(Locale.CHINA).replaceAll("[\\t\\n\\r]", " ");
if (sql.matches(REGEX))
dbTypeEnum = DBTypeEnum.WRITE;
dbTypeEnum = DBTypeEnum.READ;
}
} else {
dbTypeEnum = DBTypeEnum.WRITE;
}
_log.warn("设置方法[{}] use [{}] Strategy, SqlCommandType [{}]..", ms.getId(), dbTypeEnum.name(), ms.getSqlCommandType().name());
cachaMap.put(ms.getId(), dbTypeEnum);
}
DbContextHolder.setDbType(dbTypeEnum);
}
return invocation.proceed();
}
@Override
public Object plugin(Object target) {
if (target instanceof Executor) {
return Plugin.wrap(target, this);
} else {
return target;
}
}
@Override
public void setProperties(Properties properties) {
}
}
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