结对开发地铁

由于自身技术限制，目前只写出了对线路的查询和查出同一线路的信息，对于换乘问题还没有解决，接下来就谈谈我的理解。

List<Subway> subwayn = dao.getSubwayByNumber(number); 1
if(subwayn == null) {
req.setAttribute("info", "无此路线！");
req.getRequestDispatcher("road.jsp").forward(req,resp);
} else {
req.setAttribute("subwayn", subwayn); 2

2中的subwayn是获取1中的subwayn的值，2中的"subwayn"是设置一个节点，将subwayn的值赋予"subwayn"，且"subwayn"需要与jsp中<c:forEach items="${subwayn}" var="item" varStatus="status">中的加红字体一致。

查询线路信息：

public List<Subway> getSubwayByNumber(int number) {
String sql = "select * from subwayn where number = '" + number + "'";
List<Subway> list = new ArrayList<>();
Connection conn = Util.getConnection();
Statement state = null;
ResultSet rs = null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
Subway subwayn = null;
while (rs.next()) {
int id = rs.getInt("id");
String name = rs.getString("name");
String info = rs.getString("info");
subwayn = new Subway(id, number, name, info);
list.add(subwayn);
}

通过id查找同一线路的信息，并将其打印出来。

途经信息查询：

private void getSubwayByName(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String name1 = req.getParameter("name1");
String name2 = req.getParameter("name2");
Subway subwayn1 = dao.getSubwayByName(name1);
Subway subwayn2 = dao.getSubwayByName(name2);
List<Subway> subwayn3=new ArrayList<>();
subwayn3 = dao.search(name1,name2);
int m = 0;
if(subwayn1.getNumber()==subwayn2.getNumber()){
m = Math.abs(subwayn1.getId()-subwayn2.getId());
}

name1是起点站名，name2是终点站名，m为两站点id值得差表示途径几站，subwayn3为新建一个表，将途经站点信息储存。

String sql3 = "select * from subwayn where id between '" + subwayn1.getId() + "' and '" + subwayn2.getId() + "'";

查询id值在subwayn1和subwayn2之间的站点

还有就是通过对数据库的学习，我对SELECT语句的理解和运用更加深刻了。

对于换乘的问题，我们还将继续讨论。