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

public class JDBCConn {
    public static final String DRIVER = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
    public static final String URL = "jdbc:sqlserver://localhost:1433;DatabaseName=books";
    public static final String USER = "sa";
    public static final String PWD = "ok";
    private Connection conn = null;

    public Connection getConn() {
        try {
            Class.forName(DRIVER);
            conn = DriverManager.getConnection(URL,USER,PWD);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return conn;
    }
}

------解决方案--------------------
   你的数据库端口配置自己改成8080了吗，8080一般是给mysql预留的端口？SQLServer应该是1443吧！

------解决方案--------------------
   打开配置工具SQL server Configuration Manager,SQLEXPRESS协议中启动tic/ip.  

双击打开tip/ip属性。ipAll部分把tcp端口设置为1433.重新启动电脑  


------解决方案--------------------
url写的有问题
应该是
url = “jdbc:microsoft:sqlserver://localhost:1433;databaseName=数据库名”；