数据源

package edu.sdkd.datasource;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.Properties;

import edu.sdkd.utils.Utils;

public class MyDataSource {

 private static Properties properties = Utils.readProperties("db.properties");

 private static String driver = properties.getProperty("driver");
 private static String url = properties.getProperty("url");
 private static String user = properties.getProperty("user");
 private static String password = properties.getProperty("password");

 private static int initCount = Integer.valueOf(properties.getProperty("initCount"));
 private static int maxCount = Integer.valueOf(properties.getProperty("maxCount"));
 private static int currentCount = Integer.valueOf(properties.getProperty("currentCount"));
 
 LinkedList<Connection> connectionsPool = new LinkedList<Connection>();

 {
  for (int i = 0; i < initCount; i++) {
   try {
    this.connectionsPool.addLast(this.createConnection());
    this.currentCount++;
   } catch (SQLException e) {
    throw new ExceptionInInitializerError();
   }
  }
 }
 
 static{
  try {
   Class.forName(driver);
  } catch (ClassNotFoundException e) {
   new RuntimeException("加载驱动失败");
  }
 }
 
 private static final MyDataSource myDataSource = new MyDataSource();

 private MyDataSource() {

 }

 public static MyDataSource getMyDataSource() {
  return myDataSource;
 }

 public Connection getConnection() throws SQLException {
  synchronized (connectionsPool) {
   if (this.connectionsPool.size() > 0)
    return this.connectionsPool.removeFirst();
   if (this.currentCount < this.maxCount) {
    this.currentCount++;
    return this.createConnection();
   }
   throw new SQLException("已没有连接");
  }
 }

 public void free(Connection conn) {
  this.connectionsPool.addLast(conn);
 }

 private Connection createConnection() throws SQLException {
  Connection realConn = DriverManager.getConnection(url, user, password);
  MyConnectionHandler proxy = new MyConnectionHandler(this);
  return proxy.bind(realConn);

 }
}

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package edu.sdkd.datasource;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;

class MyConnectionHandler implements InvocationHandler {

 private Connection realConnection;
 private Connection warpedConnection;
 private MyDataSource dataSource;
 
 MyConnectionHandler(MyDataSource dataSource) {
  this.dataSource = dataSource;
 }

 Connection bind(Connection realConn) {
  this.realConnection = realConn;
  this.warpedConnection = (Connection)Proxy.newProxyInstance(this.getClass().getClassLoader(),
    new Class[] { Connection.class }, this);
  return warpedConnection;
 }

 public Object invoke(Object proxy, Method method, Object[] args)
   throws Throwable {
  if("close".equals(method.getName())){
   this.dataSource.connectionsPool.addLast(this.warpedConnection);
  }
  return method.invoke(this.realConnection, args);
 }

}

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package edu.sdkd.datasource;

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 MyConnection implements Connection{
 private Connection realConnection;
 private MyDataSource dataSource;
 
 MyConnection(Connection realConnection, MyDataSource dataSource){
  this.realConnection = realConnection;
  this.dataSource = dataSource;
 }

 public void clearWarnings() throws SQLException {
  this.realConnection.clearWarnings();
 }

 public void close() throws SQLException {
  this.dataSource.connectionsPool.addLast(this);
 }

 public void commit() throws SQLException {
  this.realConnection.commit();
 }

 public Array createArrayOf(String typeName, Object[] elements)
   throws SQLException {
  return this.realConnection.createArrayOf(typeName, elements);
 }

 public Blob createBlob() throws SQLException {
  return this.realConnection.createBlob();
 }

 public Clob createClob() throws SQLException {
  return this.realConnection.createClob();
 }

 public NClob createNClob() throws SQLException {
  return this.realConnection.createNClob();
 }

 public SQLXML createSQLXML() throws SQLException {
  return this.realConnection.createSQLXML();
 }

 public Statement createStatement() throws SQLException {
  return this.realConnection.createStatement();
 }

 public Statement createStatement(int resultSetType, int resultSetConcurrency)
   throws SQLException {
  return this.realConnection.createStatement();
 }

 public void abort(Executor executor) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
   throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public Struct createStruct(String typeName, Object[] attributes) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public boolean getAutoCommit() throws SQLException {
  // TODO Auto-generated method stub
  return false;
 }

 public String getCatalog() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public Properties getClientInfo() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public String getClientInfo(String name) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public int getHoldability() throws SQLException {
  // TODO Auto-generated method stub
  return 0;
 }

 public DatabaseMetaData getMetaData() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public int getNetworkTimeout() throws SQLException {
  // TODO Auto-generated method stub
  return 0;
 }

 public String getSchema() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public int getTransactionIsolation() throws SQLException {
  // TODO Auto-generated method stub
  return 0;
 }

 public Map<String, Class<?>> getTypeMap() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public SQLWarning getWarnings() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public boolean isClosed() throws SQLException {
  // TODO Auto-generated method stub
  return false;
 }

 public boolean isReadOnly() throws SQLException {
  // TODO Auto-generated method stub
  return false;
 }

 public boolean isValid(int timeout) throws SQLException {
  // TODO Auto-generated method stub
  return false;
 }

 public String nativeSQL(String sql) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public CallableStatement prepareCall(String sql) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency,
   int resultSetHoldability) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql, int[] columnIndexes) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql, String[] columnNames) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
   throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency,
   int resultSetHoldability) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public void releaseSavepoint(Savepoint savepoint) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void rollback() throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void rollback(Savepoint savepoint) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setAutoCommit(boolean autoCommit) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setCatalog(String catalog) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setClientInfo(Properties properties) throws SQLClientInfoException {
  // TODO Auto-generated method stub
  
 }

 public void setClientInfo(String name, String value) throws SQLClientInfoException {
  // TODO Auto-generated method stub
  
 }

 public void setHoldability(int holdability) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setReadOnly(boolean readOnly) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public Savepoint setSavepoint() throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public Savepoint setSavepoint(String name) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }

 public void setSchema(String schema) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setTransactionIsolation(int level) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
  // TODO Auto-generated method stub
  
 }

 public boolean isWrapperFor(Class<?> iface) throws SQLException {
  // TODO Auto-generated method stub
  return false;
 }

 public <T> T unwrap(Class<T> iface) throws SQLException {
  // TODO Auto-generated method stub
  return null;
 }
}

 

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