我想说您的代码是许多最差做法的示例。让我来计算一下：
你走错了路。重新考虑一下。
我认为您会发现此代码更有用。
package persistence;
import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class DatabaseUtils
{
public static Connection createConnection(String driver, String url, String username, String password) throws ClassNotFoundException, sqlException
{
Class.forName(driver);
if ((username == null) || (password == null) || (username.trim().length() == 0) || (password.trim().length() == 0))
{
return DriverManager.getConnection(url);
}
else
{
return DriverManager.getConnection(url, username, password);
}
}
public static void close(Connection connection)
{
try
{
if (connection != null)
{
connection.close();
}
}
catch (sqlException e)
{
e.printStackTrace();
}
}
public static void close(Statement st)
{
try
{
if (st != null)
{
st.close();
}
}
catch (sqlException e)
{
e.printStackTrace();
}
}
public static void close(ResultSet rs)
{
try
{
if (rs != null)
{
rs.close();
}
}
catch (sqlException e)
{
e.printStackTrace();
}
}
public static void rollback(Connection connection)
{
try
{
if (connection != null)
{
connection.rollback();
}
}
catch (sqlException e)
{
e.printStackTrace();
}
}
public static List<Map<String, Object>> map(ResultSet rs) throws sqlException
{
List<Map<String, Object>> results = new ArrayList<Map<String, Object>>();
try
{
if (rs != null)
{
ResultSetMetaData Meta = rs.getMetaData();
int numColumns = Meta.getColumnCount();
while (rs.next())
{
Map<String, Object> row = new HashMap<String, Object>();
for (int i = 1; i <= numColumns; ++i)
{
String name = Meta.getColumnName(i);
Object value = rs.getObject(i);
row.put(name, value);
}
results.add(row);
}
}
}
finally
{
close(rs);
}
return results;
}
}
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