程序不會讀我的if語句

我正在做這個項目，我差不多完成了。我花了一段時間才真正讓代碼真正運行，但我終於明白了。我的任務是製作HTML表單，使用JSP將其連接到MySQL，並將值插入數據庫或從數據庫中刪除值。它也是密碼保護的。就像我說過的，我已經得到它來編譯沒有錯誤，但是我已經實現的If語句沒有被拾取。我想知道你們是否都可以幫我弄清楚爲什麼會發生這種情況。我要粘貼我的HTML代碼，然後我的JSP。程序不會讀我的if語句

HTML代碼

<?xml version = "1.0" encoding = "utf-8"?> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 

<html xmlns = "http://www.w3.org/1999/xhtml"> 
<head> 
<title> Assignment 3 </title> 
</head> 
<body> 
<h3> Song Name Form </h3> 
<form action = "hgooding.jsp" method = "post"> 

    <table border = "1"> 
     <tr> 
      <td>Song Title: </td> 
      <td> <input type = "text" name = "song"/> </td> 
     </tr> 
     <tr> 
      <td>Artist </td> 
      <td> <input type = "text" name = "artist"/> </td> 
     </tr> 
     <tr> 
      <td>Password: </td>    
      <td> <input type = "password" name = "pass1" 
       size = "20"/> </td> 
     </tr> 
     </table> 
     <br> 
      <input type = "radio" name = "option" value = "add"/> Add 
      <input type = "radio" name = "option" value = "delete"/> Delete 

       <br>  
         <input type = "submit" value = "Submit" /> 

</form> 
</body> 
</html>

JSP代碼

<%@ page import = "java.sql.*" %> 

<html> 
<head> <title> Database jsp </title></head> 
<body> 
<% 

String connectionURL = "jdbc:mysql://sql.njit.edu:3306/hg33"; 
    Connection connection = null; 
    Statement stm = null; 
    ResultSet rst=null; 

Class.forName("com.mysql.jdbc.Driver").newInstance(); 
    connection = DriverManager.getConnection(connectionURL, "hg33", "grapes34"); 
    String song = request.getParameter("song"); 
    String artist = request.getParameter("artist"); 
    String action = request.getParameter("option"); 
    String pass2 = request.getParameter("pass1"); 
    Statement stminsert = null; 
    stminsert = connection.createStatement(); 
if (pass2 == "apples4") 
    {  
    if (request.getParameter("action").equals("add")) 
    { 
     String sqlupdate1=("INSERT INTO Songs VALUES('"+song+"', '"+artist+"')"); 
    stm.executeUpdate(sqlupdate1); 
     out.println("Hi!"); 
} 
if (request.getParameter("action").equals("delete")) 
{ 
    String sqlupdate2=("DELETE FROM Music WHERE Song =('"+song+"')"); 
    stm.executeUpdate(sqlupdate2); 
}  

rst = stm.executeQuery("SELECT * from Music"); 
    } 
else 
    { 
    out.println("Password is not correct!!!"); 
    }   
    out.println("insert attempted"); 
%> 
</body> 
</html>

來源

2013-05-15 user2383996

在行動可變選項，if語句不工作？ 'if（pass2 ==「apples4」）..'，'if（request.getParameter（「action」）。equals（「delete」））....'，或者if（request.getParameter（「action 「）.equals（」add「）） {' –

可能的重複[如何比較Java中的字符串？]（http://stackoverflow.com/questions/513832/how-do-i-compare-strings-在-JAVA） – EJP

我想在烏爾if語句應該是這樣的

if (action.equals("add")){.........................}

或

if (action == "add"){.........................}

01條件

代替

if (request.getParameter("action").equals("add")){....................}

怎麼把ü趕上這樣

String action = request.getParameter("option")

來源

2013-05-15 04:08:12 NewBuddy

程序不會讀我的if語句

回答

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