Question

如何在下面重写我的代码，直接在我的网页上而不是在控制台上打印结果？

public Observable<LinkedList<WeatherInfo>> getWeatherData(final String payload, final TempUnit tempUnit) {

        PublishSubject weatherInfoPublisher = PublishSubject.create();

        RetrofitProvider.getInstance().getCurrentWeather(payload + ",us", translateTempUnit(tempUnit))
            .flatMap(new Function<String, ObservableSource<String>>() {
                @Override
                public ObservableSource<String> apply(String todayResponse) throws Exception {

                    Log.d(TAG, "Received today weather: " + todayResponse);

                    parseTodayData(todayResponse, weatherDataList);
                    return RetrofitProvider.getInstance().getForecastWeather(
                            payload + ",us", translateTempUnit(tempUnit), FORECAST_DAYS);
                }
            })
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribeWith(new DisposableObserver<String>() {
                @Override
                public void onNext(String futureResponse) {

                    Log.d(TAG, "Received future weather: " + futureResponse);
                    parseFutureData(futureResponse, weatherDataList);

                    weatherInfoPublisher.onNext(weatherDataList);
                    weatherInfoPublisher.onComplete();
                }

                @Override
                public void onError(Throwable e) {
                    Log.e(TAG, "The error is, " + e.getMessage());
                }

                @Override
                public void onComplete() {

                }
            });

        return weatherInfoPublisher;
    }

Answer 1

一种方法是从servlet响应中获取编写器，然后编写所需的HTML内容。我对您的doSQL()方法进行了轻微的重构，以接受PrintWriter作为参数。

public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
    PrintWriter pw = response.getWriter();
    doSQL(pw);
}

public static void doSQL(PrintWriter pw) {
    try {
        String url = "jdbc:msql://...";
        Connection conn = DriverManager.getConnection(url,"user","password");
        Statement stmt = conn.createStatement();
        ResultSet rs;

        rs = stmt.executeQuery("SELECT Lname FROM Customers WHERE Snum = 2001");
        pw.println("<html><table>");
        while (rs.next()) {
            // you only select one field, but you can easily adapt
            // this code to have more fields (i.e. table columns)
            String lastName = rs.getString("Lname");
            pw.println("<tr><td>" + lastname + "</td></tr>");
        }
        pw.println("</table></html>");
        conn.close();
    } catch (Exception e) {

        System.err.println("Got an exception! ");
        System.err.println(e.getMessage());
    }
}

Answer 2

您需要返回结果集。

public static ResultSet doSQL() {
        try {
            String url = "jdbc:msql://...";
            Connection conn = DriverManager.getConnection(url,"user","password");
            Statement stmt = conn.createStatement();
            ResultSet rs;

            rs = stmt.executeQuery("SELECT Lname FROM Customers WHERE Snum = 2001");

            conn.close();
            return rs;
        } catch (Exception e) {

            System.err.println("Got an exception! ");
            System.err.println(e.getMessage());
        }

        return null
    }

在你的servlet中，获取doSQL（）;

ResultSet rs = MyStaticFile.doSQL();
int rowCount = 0;

 out.println("<P ALIGN='center'><TABLE BORDER=1>");
 ResultSetMetaData rsmd = rs.getMetaData();
 int columnCount = rsmd.getColumnCount();
 // table header
 out.println("<TR>");
 for (int i = 0; i < columnCount; i++) {
   out.println("<TH>" + rsmd.getColumnLabel(i + 1) + "</TH>");
   }
 out.println("</TR>");
 // the data
 while (rs.next()) {
  rowCount++;
  out.println("<TR>");
  for (int i = 0; i < columnCount; i++) {
    out.println("<TD>" + rs.getString(i + 1) + "</TD>");
    }
  out.println("</TR>");
  }
 out.println("</TABLE></P>");

这不是一个完整的例子，还没有完全测试。这个参考将让你了解如何做到这一点。顺便说一下，不要使用静态进行数据库操作。您可以将其用于学习目的。

Answer 3

以下是使用GET方法引用servlet响应代码为html的示例，同样可以为POST方法编写。在servlet中添加以下代码。

  public void doGet(HttpServletRequest request, HttpServletResponse 
  response) throws IOException { 
PrintWriter out = response.getWriter(  ); 
response.setContentType("text/html"); 
    out.println("<html>");
    out.println("<head>");

out.println("<title> Any Title </title>");
    out.println("</head>");
    out.println("<body>");
    out.println("<H1>Last Name from a Servlet</H1></br>"); 
try {
        String url = "jdbc:msql://...";
        Connection conn = DriverManager.getConnection(url,"user","password");
        Statement stmt = conn.createStatement();
        ResultSet rs;

        rs = stmt.executeQuery("SELECT Lname FROM Customers WHERE Snum = 2001");
        while ( rs.next() ) {

            // I want to print the ResultSet directly on my HTML page, how may I go about doing that?
            String lastName = rs.getString("Lname");
            out.println("<H1>"+ lastName +"</H1></br>");
            System.out.println(lastName);
        }
        conn.close();
    } catch (Exception e) {

        System.err.println("Got an exception! ");
        System.err.println(e.getMessage());
    }

      out.println("</body>");
      out.println("</html>");

      out.close();

}

将SQL选择结果集直接打印到HTML网页上？

3 个答案: