【数工】问题来了

package edu.jmi.booksmanage.dbo;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DBOperation {
private static final String URL="jdbc:sqlserver://localhost:1433;databasename=Booksmanager";
private static final String USERNAME="sa";
private static final String PASSWORD="199555";
public static Connection getConnection(){
Connection conn=null;
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
public static void closeConnection(Connection conn){
try {
if(conn!=null && !conn.isClosed())
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void closeStatement(Statement st){
try {
if(st!=null && !st.isClosed())
st.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void closeResultSet(ResultSet rs){
try {
if(rs!=null && !rs.isClosed())
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
getConnection();
}
}

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 edu.jmi.booksmanage.dbo.DBOperation.getConnection(DBOperation.java:18)
at edu.jmi.booksmanage.dbo.DBOperation.main(DBOperation.java:53)