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)