如何通过servlet在jsp中显示用户定义的arraylist，如下所示。 我已经创建了用户定义的arraylist并传递给了jsp

Question

我应该怎么做？ 使用桌子吗？ 你能举个例子吗？ 我刚来这地方！ 帮助将不胜感激。输出应如下所示：

2018-07-30        2018-07-31     2018-08-01
min temp:27       min temp:30    min temp:28
max temp:29       max temp:34    max temp:32
humidity:74       humidity:70    humidity:75

在Forecast.jsp页面中

  <c:forEach var="weather" items="${weatherList}">                       
         <c:out value="${weather.date}"/><br> 
         <c:out value="${weather.minTemp}"/><br>
         <c:out value="${weather.maxTemp}"/><br>
         <c:out value="${weather.humidity} "/><br>
        </c:forEach>        

在Servlet类中，im从数据库获取值并将其添加到arraylist

     ArrayList<WeatherDataDto> weatherList = new ArrayList<>();
        try {
            String query = "select * from weather_data where date>='2018-07-30'";
            Statement stmt = connection.createStatement();
            ResultSet rs = stmt.executeQuery(query);    
            while (rs.next()) {
                String date = rs.getString(1);
                int minTemp = rs.getInt(2);
                int maxTemp = rs.getInt(3);
                int humidity = rs.getInt(4);
                WeatherDataDto weatherDto = new WeatherDataDto(date, minTemp, maxTemp, humidity);
                weatherList.add(weatherDto);
        }
            rs.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }

request.setAttribute("weatherList", weatherList);
        RequestDispatcher dispatcher = request.getRequestDispatcher("/forecast.jsp");
        dispatcher.forward(request, response);

//这是我的bean类

public class WeatherDataDto {

    private String date;
    private int minTemp;
    private int maxTemp;
    private int humidity;


    public WeatherDataDto(){        
    }

    public WeatherDataDto(String date, int minTemp,int maxTemp, int humidity) {
        super();
        this.date = date;
        this.minTemp = minTemp;
        this.maxTemp = maxTemp;
        this.humidity = humidity;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public int getMinTemp() {
        return minTemp;
    }

    public void setMinTemp(int minTemp) {
        this.minTemp = minTemp;
    }

    public int getMaxTemp() {
        return maxTemp;
    }

    public void setMaxTemp(int maxTemp) {
        this.maxTemp = maxTemp;
    }

    public int getHumidity() {
        return humidity;
    }

    public void setHumidity(int humidity) {
        this.humidity = humidity;
    }

我只想显示上述格式的清单。 帮帮我

Answer 1

<table>
          <c:forEach var="weather" items="${weatherList}" varStatus="index">                       
            <tr>
              <c:forEach begin="0" end="${fn:length(weatherList)" varStatus="loop">
                 <td><c:out value="${weatherList[loop].date}"/></td> 
              </c:forEach>
            </tr>
            <tr>
              <c:forEach begin="0" end="${fn:length(weatherList)" varStatus="loop">
                 <td><c:out value="${weatherList[loop].minTemp}"/></td> 
              </c:forEach>
            </tr>
           <tr>
              <c:forEach begin="0" end="${fn:length(weatherList)" varStatus="loop">
                 <td><c:out value="${weatherList[loop].maxTemp}"/></td> 
              </c:forEach>
            </tr>
          <tr>
              <c:forEach begin="0" end="${fn:length(weatherList)" varStatus="loop">
                 <td><c:out value="${weatherList[loop].humidity}"/></td> 
              </c:forEach>
            </tr>
        </c:forEach> 
        </table>

尝试这个