数据库连接池

package AnLi;

import java.sql.Connection;

public interface IDBConnection {
//初始化连接
    void init();
//获取连接
    Connection getConnection();
//关闭连接
    void close(Connection con);
}

package AnLi;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class MySQLConnection {
    private static String DRIVER="com.mysql.jdbc.Driver";
    private static String URL="jdbc:mysql://127.0.0.1:3306/nc";
    private static String USER="root";
    private static String PASSWORD="";

    public Connection getConnection(){
        Connection con=null;

        try {
            Class.forName(DRIVER);
            con= DriverManager.getConnection(URL,USER,PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }

        return con;

    }

}

package AnLi;

import java.sql.Connection;
import java.util.LinkedList;

public class MySQLConnectionPool implements IDBConnection{
    private static final int minConnection=1;

    private static final int maxConnection=10;

    private static final LinkedList<Connection> pools=new LinkedList<Connection>();
    private MySQLConnection mySQLConnection=new MySQLConnection();

   @Override
    public void init() {
        Connection con=null;
        for (int i=0;i<minConnection;i++){
        con=mySQLConnection.getConnection();
        pools.add(con);
        }
    }
@Override
    public synchronized Connection getConnection() {
       @SuppressWarnings("ubused")
               Connection con=null;
       if(pools.size()==0){
           con=mySQLConnection.getConnection();
       }else{
           con=pools.remove();

       }
        return con;
    }
@Override
    public synchronized void close(Connection con) {
        if(pools.size()<maxConnection){
            pools.add(con);
        }
    }
}

package AnLi;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class TestCustonConnection {
    public static void main(String[] args) {
        IDBConnection dbCon=new MySQLConnectionPool();
        dbCon.init();
        long start=System.currentTimeMillis();

            try {
                for(int i=0;i<100;i++) {
                    Connection con = dbCon.getConnection();
                    String sql = "select * from employees";
                    PreparedStatement ps = con.prepareStatement(sql);
                    ResultSet rs=ps.executeQuery();
                    System.out.println(rs);
                    ps.close();
                    dbCon.close(con);
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            long end =System.currentTimeMillis();
             System.out.println(end-start);

    }
}