JAVA 连接SQLserver数据库报错解决思路

package com.em.junit;

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

public class Sqlconnention {
    public static void main(String[] args) {
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            try {
                Connection con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=ExaManager", "sa", "hekunlun");
                String sql = "select ?, ? from tb_studentLogin";
                PreparedStatement pstmt = null;
                pstmt = con.prepareStatement(sql);
                pstmt.setString(1, "studentNumber");
                pstmt.setString(2, "studentPassword");
                ResultSet rs = pstmt.executeQuery();
                while(rs.next()){
                    System.out.println(rs.getString(1));
                    System.out.println(rs.getString(2));
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
}

com.microsoft.sqlserver.jdbc.SQLServerException: 到主机  的 TCP/IP 连接失败。 java.net.ConnectException: Connection refused: connect
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(Unknown Source)
    at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(Unknown Source)
    at java.sql.DriverManager.getConnection(DriverManager.java:582)
    at java.sql.DriverManager.getConnection(DriverManager.java:185)
    at com.em.junit.Sqlconnention.main(Sqlconnention.java:16)