我自己跟著視頻寫的代碼。調(diào)用的是mysql自帶的數(shù)據(jù)庫(kù)world。

這個(gè)是CityDAo里面的

public ArrayList<City>getAllCities(){

Connection conn=null;

PreparedStatement stmt=null;

ResultSet rs=null;

ArrayList<City> list=new ArrayList<City>();//城市集合

try{

conn=DBHelper.getConnection();

String sql="select *from city where Name='Shanghai';"; ? //SQL

stmt=conn.prepareStatement(sql);

rs=stmt.executeQuery();

//Statement stmt = conn.createStatement(); ?

//ResultSet rs = stmt.executeQuery(sql); ?

while(rs.next()){

City city=new City();

city.setId(rs.getInt("ID"));

city.setName(rs.getString("Name"));

city.setCountryCode(rs.getString("CountryCode"));

city.setDistrict(rs.getString("District"));

city.setPopulation(rs.getInt("Population"));

list.add(city); ?//每次遍歷加一個(gè)城市

}

return list; ? //返回

index.jsp文件

? <h1>數(shù)據(jù)庫(kù)city展示</h1>

? <hr>

<center>

<table>

<thead>

<tr><th>ID</th><th>名字</th><th>國(guó)家</th><th>地區(qū)</th><th>人口數(shù)量</th></tr>

</thead>

<tbody>

<%

CityDAO cityDao=new CityDAO();

ArrayList<City>list=cityDao.getAllCities();

if(list!=null&&list.size()>0){

for(int i=0;i<list.size();i++){

City city=list.get(i);

%>

?

<tr><td><%=city.getId() %></td><td><%=city.getName() %></td><td><%=city.getCountryCode() %></td><td><%=city.getDistrict() %></td><td><%=city.getPopulation() %></td></tr>

<%

}

}

%>

</tbody>

</table>

</center>

數(shù)據(jù)庫(kù)連接正常，網(wǎng)頁(yè)顯示只有第一行的表頭，沒有數(shù)據(jù)。求解答