提交按鈕無需發帖即可清除表格

因此，我嘗試使用簡單的表單從用戶獲取輸入，從數據庫中檢索必要的信息併發布。但是，在HTML頁面上，提交按鈕只是清除表單。以下是操作中引用的html文件和java文件。我知道與數據庫交互的文件丟失了，但我認爲我的問題在於其中之一。如果需要，我可以稍後發佈。我的問題是，爲什麼提交按鈕會清除表單而不是將您帶入網站的「操作」中？提交按鈕無需發帖即可清除表格

<form> 
     <FORM METHOD=POST ACTION = "http://uml.cs.uga.edu:8080/michael_crosby_courses/Schedule"> 
     Class 1: <input type=text name="Class1"><br> 
     Class 2: <input type=text name="Class2"><br> 
     Class 3: <input type=text name="Class3"><br> 
     Class 4: <input type=text name="Class4"><br> 
     <input type=submit> 
</form> 





import java.io.*; 
import java.util.*; 
import javax.servlet.*; 
import javax.servlet.http.*; 

public class Schedule extends HttpServlet { 

public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { 

    PrintWriter toClient = res.getWriter(); 
    String field; 
    String val; 
    Vector classes = null; 
    Vector totalHours = null; 
    String query = null, query2 = null; 
    String class1 = null, class2 = null, class3 = null, class4 = null; 
    int i, sum=0; 

    res.setContentType("text/html"); 

    toClient.println("<html>"); 
    toClient.println("<title>MyEcho</title>"); 
    toClient.println("<body>"); 

    Enumeration values = req.getParameterNames(); 

    if(values.hasMoreElements()) { 

     class1 = req.getParameter("Class 1"); 
     class2 = req.getParameter("Class 2"); 
     class3 = req.getParameter("Class 3"); 
     class4 = req.getParameter("Class 4"); 
     toClient.println("<P><P><B>Your Schedule:</B></P></P>"); 
     query = "select * from csci_section where number = " + class1 + " or number = " + class2 + " or number = " + class3 + " or number = " + class4 + ";"; 

    } 

    query2 = "select credit from csci_section where number = " + class1 + " or number = " + class2 + " or number = " + class3 + " or number = " + class4 + ";"; 

    if(query == null) 

     toClient.println("<P><P><B>No query given; resubmit </B>"); 

    else if(1==1) {    //if the request did not return anything, i.e. the number given is not a class 

    } else{ 

     toClient.println("<P><B>Running search for classes: </B>" + class1 + ", " + class2 + ", " + class3 + ", " + class4 + ", " + "<P><P>"); 

     classes = AccessMySQL.Execute(query); 
     totalHours = AccessMySQL.Execute(query2); 
     toClient.println("<P><P><B>Received classes: </B></P></P>"); 

     for(i = 0; i < classes.size(); i++){ //prints out info 

      toClient.println("<p><tt>" + (String)classes.elementAt(i) + "</tt></p>"); 

     } 

     for(i=0; i < totalHours.size(); i++){ 
      sum += Integer.parseInt((totalHours.elementAt(i)).toString()); 
     } 
     toClient.println("<p><tt>The total number of class hours is: " + sum + "</tt></p>"); 
    } 

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

    toClient.close(); 


} //closes doPost

}

來源

2012-11-14 Michael

男人試一下，問一個具體問題 – Ali

你的HTML無效。驗證它，然後嘗試發佈它，然後調試您的服務器端代碼。 –

因爲你有兩個<form>標籤。第一個（沒有動作）就是瀏覽器用戶。刪除它，它應該開始按預期工作。

<form> <-- Remove this one 
    <FORM METHOD=POST ACTION = "http://uml.cs.uga.edu:8080/michael_crosby_courses/Schedule">

來源

2012-11-14 19:05:22 mprivat

提交按鈕無需發帖即可清除表格

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