java当中JDBC当中请给出一个SQLServer DataSource and SingleTon例子

Posted 2022-12-22 haima1949

[学习笔记]

5.SQLServer DataSource and SingleTon：

import net.sourceforge.jtds.jdbcx.*;
import java.sql.*;
import javax.sql.*;

public class SqlserverSingletonDataSource
static private JtdsDataSource ds;
private Connection con;
private SqlserverSingletonDataSource()

try
ds = new JtdsDataSource();
ds.setServerName("localhost");
ds.setDatabaseName("pubs");
ds.setUser("sa");
ds.setPassword("");

catch (Exception e)



public static Connection getConnection() throws Exception
if (ds == null)
new SqlserverSingletonDataSource();

Connection con =null;
try
con = ds.getConnection();
catch (SQLException ex)


return con;

测试程序：

/*when you use single step to debug the program, you can find that Singleton only
is executed once.*/
import java.sql.*;
import javax.sql.*;

public class testSqlserverSingletonDataSource

public static void main(String args[])
Connection con;

try
con = SqlserverSingletonDataSource.getConnection();
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from authors");
while (rs.next())
System.out.print(rs.getString("au_id") + " ");
System.out.println(rs.getString("au_lname"));



catch (Exception e)


System.out.println("the following is the second time ");

try
con = SqlserverSingletonDataSource.getConnection();
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from authors");
while (rs.next())
System.out.print(rs.getString("au_id") + " ");
System.out.println(rs.getString("au_lname"));



catch (Exception e)

文章转载自原文：https://blog.csdn.net/qq_43650923/article/details/100655993