如何只用4步，实现一个自定义JDBC驱动？
Posted 麒思妙想
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了如何只用4步，实现一个自定义JDBC驱动？相关的知识，希望对你有一定的参考价值。
如何只用4步，实现一个自定义JDBC驱动？ 那么今天就让我们尝试来完成一个csv-jdbc驱动，并完成简单查询。
JqDriver.java
首先创建驱动类，这里将 jdbc url 里的路径截取出来，在创建 connection 的时候传递进去。
package com.dafei1288.jimsql.jdbc;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.DriverPropertyInfo;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.Properties;
import java.util.logging.Logger;
public class JqDriver implements Driver
private static final JqDriver INSTANCE = new JqDriver();
private static final String DEFAULT_URL = "jdbc:jimsql:";
private static String DATADIR = "/tmp";
private static final ThreadLocal<Connection> DEFAULT_CONNECTION =
new ThreadLocal<>();
private static boolean registered;
static
load();
private static JqDriver load()
try
if (!registered)
registered = true;
DriverManager.registerDriver(INSTANCE);
catch (SQLException e)
e.printStackTrace();
return INSTANCE;
@Override
public Connection connect(String url, Properties info) throws SQLException
System.out.println(url);
System.out.println(info);
String filepath = url.replace(DEFAULT_URL,"");
System.out.println(filepath);
return new JqConnection(filepath);
@Override
public boolean acceptsURL(String url) throws SQLException
System.out.println("acceptsURL ? "+url);
return false;
@Override
public DriverPropertyInfo[] getPropertyInfo(String url, Properties info) throws SQLException
return new DriverPropertyInfo[0];
@Override
public int getMajorVersion()
return 0;
@Override
public int getMinorVersion()
return 0;
@Override
public boolean jdbcCompliant()
return false;
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException
return null;
JqConnection.java
接下来我们要实现connection类，接受文本库的基础路径，并实现创建 createStatement方法
package com.dafei1288.jimsql.jdbc;
import java.sql.Array;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.NClob;
import java.sql.PreparedStatement;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;
public class JqConnection implements Connection
private String datapath;
JqConnection(String datapath)
this.datapath = datapath;
@Override
public Statement createStatement() throws SQLException
return new JqStatement(datapath);
@Override
public PreparedStatement prepareStatement(String sql) throws SQLException
return null;
@Override
public CallableStatement prepareCall(String sql) throws SQLException
return null;
@Override
public String nativeSQL(String sql) throws SQLException
return null;
@Override
public void setAutoCommit(boolean autoCommit) throws SQLException
@Override
public boolean getAutoCommit() throws SQLException
return false;
@Override
public void commit() throws SQLException
@Override
public void rollback() throws SQLException
@Override
public void close() throws SQLException
@Override
public boolean isClosed() throws SQLException
return false;
@Override
public DatabaseMetaData getMetaData() throws SQLException
return null;
@Override
public void setReadOnly(boolean readOnly) throws SQLException
@Override
public boolean isReadOnly() throws SQLException
return false;
@Override
public void setCatalog(String catalog) throws SQLException
@Override
public String getCatalog() throws SQLException
return null;
@Override
public void setTransactionIsolation(int level) throws SQLException
@Override
public int getTransactionIsolation() throws SQLException
return 0;
@Override
public SQLWarning getWarnings() throws SQLException
return null;
@Override
public void clearWarnings() throws SQLException
@Override
public Statement createStatement(int resultSetType, int resultSetConcurrency)
throws SQLException
return null;
@Override
public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
throws SQLException
return null;
@Override
public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency)
throws SQLException
return null;
@Override
public Map<String, Class<?>> getTypeMap() throws SQLException
return null;
@Override
public void setTypeMap(Map<String, Class<?>> map) throws SQLException
@Override
public void setHoldability(int holdability) throws SQLException
@Override
public int getHoldability() throws SQLException
return 0;
@Override
public Savepoint setSavepoint() throws SQLException
return null;
@Override
public Savepoint setSavepoint(String name) throws SQLException
return null;
@Override
public void rollback(Savepoint savepoint) throws SQLException
@Override
public void releaseSavepoint(Savepoint savepoint) throws SQLException
@Override
public Statement createStatement(int resultSetType, int resultSetConcurrency,
int resultSetHoldability) throws SQLException
return null;
@Override
public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
int resultSetHoldability) throws SQLException
return null;
@Override
public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
int resultSetHoldability) throws SQLException
return null;
@Override
public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException
return null;
@Override
public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException
return null;
@Override
public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException
return null;
@Override
public Clob createClob() throws SQLException
return null;
@Override
public Blob createBlob() throws SQLException
return null;
@Override
public NClob createNClob() throws SQLException
return null;
@Override
public SQLXML createSQLXML() throws SQLException
return null;
@Override
public boolean isValid(int timeout) throws SQLException
return false;
@Override
public void setClientInfo(String name, String value) throws SQLClientInfoException
@Override
public void setClientInfo(Properties properties) throws SQLClientInfoException
@Override
public String getClientInfo(String name) throws SQLException
return null;
@Override
public Properties getClientInfo() throws SQLException
return null;
@Override
public Array createArrayOf(String typeName, Object[] elements) throws SQLException
return null;
@Override
public Struct createStruct(String typeName, Object[] attributes) throws SQLException
return null;
@Override
public void setSchema(String schema) throws SQLException
@Override
public String getSchema() throws SQLException
return null;
@Override
public void abort(Executor executor) throws SQLException
@Override
public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException
@Override
public int getNetworkTimeout() throws SQLException
return 0;
@Override
public <T> T unwrap(Class<T> iface) throws SQLException
return null;
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException
return false;
JqStatement.java
接下来，我们实现statement类，接受connection传递下来的数据库路径，实现查询方法 executeQuery, 接收到 sql以后，进行简单分析，将表名，列名，以及数据库路径传递给 resultset
package com.dafei1288.jimsql.jdbc;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class JqStatement implements Statement
private String datapath;
JqStatement(String datapath)
this.datapath = datapath;
@Override
public ResultSet executeQuery(String sql) throws SQLException
Pattern pattern = Pattern.compile("^select (\\\\*|[a-z0-9,]*) from ([a-z]+)");
Matcher matcher = pattern.matcher(sql);
String tableName = "";
List<String> cols = null;
if(matcher.find())
String cs = matcher.group(1);
if(cs.equals("*"))
else
String[] cns =cs.split(",");
cols = Arrays.stream(cns).toList();
tableName = matcher.group(2);
JqResultSet jqResultSet = new JqResultSet(datapath,cols,tableName);
return jqResultSet;
@Override
public int executeUpdate(String sql) throws SQLException
return 0;
@Override
public void close(以上是关于如何只用4步，实现一个自定义JDBC驱动？的主要内容，如果未能解决你的问题，请参考以下文章
如何使用 JDBC 驱动程序为 django 编写自定义数据库适配器？