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这篇文章主要介绍“sharding-jdbc中AbstractDataSourceAdapter的用法”，在日常操作中，相信很多人在sharding-jdbc中AbstractDataSourceAdapter的用法问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”sharding-jdbc中AbstractDataSourceAdapter的用法”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
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本文主要研究一下sharding-jdbc的AbstractDataSourceAdapter
incubator-shardingsphere-4.0.0-RC1/sharding-jdbc/sharding-jdbc-core/src/main/java/org/apache/shardingsphere/shardingjdbc/jdbc/unsupported/AbstractUnsupportedOperationDataSource.java
public abstract class AbstractUnsupportedOperationDataSource extends WrapperAdapter implements DataSource {
@Override
public final int getLoginTimeout() throws SQLException {
throw new SQLFeatureNotSupportedException("unsupported getLoginTimeout()");
}
@Override
public final void setLoginTimeout(final int seconds) throws SQLException {
throw new SQLFeatureNotSupportedException("unsupported setLoginTimeout(int seconds)");
}
}AbstractUnsupportedOperationDataSource继承了WrapperAdapter，声明实现javax.sql.DataSource接口，其覆盖了getLoginTimeout、setLoginTimeout方法，抛出SQLFeatureNotSupportedException异常
incubator-shardingsphere-4.0.0-RC1/sharding-jdbc/sharding-jdbc-core/src/main/java/org/apache/shardingsphere/shardingjdbc/jdbc/adapter/AbstractDataSourceAdapter.java
@Getter
@Setter
public abstract class AbstractDataSourceAdapter extends AbstractUnsupportedOperationDataSource implements AutoCloseable {
private final DatabaseType databaseType;
private final Map dataSourceMap;
private ShardingTransactionManagerEngine shardingTransactionManagerEngine = new ShardingTransactionManagerEngine();
private PrintWriter logWriter = new PrintWriter(System.out);
public AbstractDataSourceAdapter(final Map dataSourceMap) throws SQLException {
databaseType = getDatabaseType(dataSourceMap.values());
shardingTransactionManagerEngine.init(databaseType, dataSourceMap);
this.dataSourceMap = dataSourceMap;
}
protected final DatabaseType getDatabaseType(final Collection dataSources) throws SQLException {
DatabaseType result = null;
for (DataSource each : dataSources) {
DatabaseType databaseType = getDatabaseType(each);
Preconditions.checkState(null == result || result.equals(databaseType), String.format("Database type inconsistent with '%s' and '%s'", result, databaseType));
result = databaseType;
}
return result;
}
private DatabaseType getDatabaseType(final DataSource dataSource) throws SQLException {
if (dataSource instanceof AbstractDataSourceAdapter) {
return ((AbstractDataSourceAdapter) dataSource).databaseType;
}
try (Connection connection = dataSource.getConnection()) {
return DatabaseType.valueFrom(connection.getMetaData().getDatabaseProductName());
}
}
@Override
public final Logger getParentLogger() {
return Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
}
@Override
public final Connection getConnection(final String username, final String password) throws SQLException {
return getConnection();
}
@Override
public void close() throws Exception {
for (DataSource each : dataSourceMap.values()) {
try {
Method method = each.getClass().getDeclaredMethod("close");
method.setAccessible(true);
method.invoke(each);
} catch (final ReflectiveOperationException ignored) {
}
}
shardingTransactionManagerEngine.close();
}
} AbstractDataSourceAdapter继承了AbstractUnsupportedOperationDataSource，实现了AutoCloseable接口；它的构造器接收一个DataSource的map，并执行shardingTransactionManagerEngine.init；close方法会遍历dataSourceMap，挨个反射调用执行close方法
incubator-shardingsphere-4.0.0-RC1/sharding-transaction/sharding-transaction-core/src/main/java/org/apache/shardingsphere/transaction/ShardingTransactionManagerEngine.java
@Slf4j
public final class ShardingTransactionManagerEngine {
private final Map transactionManagerMap = new HashMap<>();
public ShardingTransactionManagerEngine() {
loadShardingTransactionManager();
}
private void loadShardingTransactionManager() {
for (ShardingTransactionManager each : ServiceLoader.load(ShardingTransactionManager.class)) {
if (transactionManagerMap.containsKey(each.getTransactionType())) {
log.warn("Find more than one {} transaction manager implementation class, use `{}` now",
each.getTransactionType(), transactionManagerMap.get(each.getTransactionType()).getClass().getName());
continue;
}
transactionManagerMap.put(each.getTransactionType(), each);
}
}
/**
* Initialize sharding transaction managers.
*
* @param databaseType database type
* @param dataSourceMap data source map
*/
public void init(final DatabaseType databaseType, final Map dataSourceMap) {
for (Entry entry : transactionManagerMap.entrySet()) {
entry.getValue().init(databaseType, getResourceDataSources(dataSourceMap));
}
}
private Collection getResourceDataSources(final Map dataSourceMap) {
List result = new LinkedList<>();
for (Map.Entry entry : dataSourceMap.entrySet()) {
result.add(new ResourceDataSource(entry.getKey(), entry.getValue()));
}
return result;
}
/**
* Get sharding transaction manager.
*
* @param transactionType transaction type
* @return sharding transaction manager
*/
public ShardingTransactionManager getTransactionManager(final TransactionType transactionType) {
ShardingTransactionManager result = transactionManagerMap.get(transactionType);
if (TransactionType.LOCAL != transactionType) {
Preconditions.checkNotNull(result, "Cannot find transaction manager of [%s]", transactionType);
}
return result;
}
/**
* Close sharding transaction managers.
*
* @throws Exception exception
*/
public void close() throws Exception {
for (Entry entry : transactionManagerMap.entrySet()) {
entry.getValue().close();
}
}
} ShardingTransactionManagerEngine维护了ShardingTransactionManager的map，其构造器执行loadShardingTransactionManager方法，它会使用ServiceLoader.load(ShardingTransactionManager.class)加载，然后放入transactionManagerMap中；init方法会遍历transactionManagerMap，然后挨个执行init方法；close方法则遍历transactionManagerMap，挨个执行close方法
AbstractDataSourceAdapter继承了AbstractUnsupportedOperationDataSource，实现了AutoCloseable接口；它的构造器接收一个DataSource的map，并执行shardingTransactionManagerEngine.init；close方法会遍历dataSourceMap，挨个反射调用执行close方法
到此，关于“sharding-jdbc中AbstractDataSourceAdapter的用法”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注创新互联网站，小编会继续努力为大家带来更多实用的文章！