com.microsoft.sqlserver.jdbc.SQLServerException: 到主机 的 TCP/IP 连接失败。 java.net.ConnectException: Connection refused: connect

package sqlconnect;
import java.sql.*;
public class sqlconnect {
    public static void main(String[] args) {
        String user = "zcj";
        String password = "123";
        String url = "jdbc:sqlserver://localhost:1433;DatabaseName=lol";
        String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String tableName = "lol";
        String sqlstr;
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;
        try{
            Class.forName(driver);
            con = DriverManager.getConnection(url,user,password);
            stmt = con.createStatement();
            sqlstr = "insert into " + tableName + " values(‘333‘,‘333‘)";
            stmt.executeUpdate(sqlstr);
            sqlstr = "select * from " + tableName;
            rs = stmt.executeQuery(sqlstr);
            ResultSetMetaData rsmd = rs.getMetaData();
            int j = 0;
            j = rsmd.getColumnCount();
            for(int k=0;k<j;j++){
                System.out.print(rsmd.getColumnName(k+1));
                System.out.print("/t");
            }
            System.out.println();
            while(rs.next()){
                for(int i=0;i<j;i++){
                    System.out.print(rs.getString(i+1));
                    System.out.print("/t");
                }
                System.out.println();
            }
        } 
        catch(ClassNotFoundException e1){
            System.out.println("数据库驱动不存在");
            System.out.println(e1.toString());
        }
        catch(SQLException e2){
            System.out.println("数据库存在异常");
            System.out.println(e2.toString());
        }
        finally{
            try{
                if(rs != null)
                    rs.close();
                if(stmt != null)
                    stmt.close();
                if(con != null)
                    con.close();
            }
            catch(SQLException e){
                System.out.println(e.toString());
            }
        }
    }
}