[英]JDBC insert query does not update mysql database
以下代碼不會在相應的表中插入行。 我已經測試了數據庫連接,並在數據庫中運行了查詢,但是當我通過.jsp表單添加輸入時,值仍未插入,但這兩個查詢都已通過。
public class UserDao {
public String registerUser(User user){
String username = user.getUsername();
String email = user.getEmail();
String password = user.getPassword();
Connection con;
con = DBConnection.createConnection();
PreparedStatement preparedStatement;
try{
con.setAutoCommit(false);
String query = ("INSERT INTO user (username, email, password, user_id) VALUES(?, ?, ?, ?)");
preparedStatement = con.prepareStatement(query);
preparedStatement.setString(1, username);
preparedStatement.setString(2, email);
preparedStatement.setString(3, password);
preparedStatement.setString(4,null);
int i = preparedStatement.executeUpdate();
con.commit();
preparedStatement.close();
con.close();
if(i !=0 ){
return "SUCCESS";
}
}catch(SQLException e){
throw new RuntimeException(e);
}
return "Something is wrong!";
}
}
這里參考的是我的servlet類和.jsp文件看起來像:
public class UserRegistrationServlet extends HttpServlet {
public UserRegistrationServlet(){}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String userName = request.getParameter("username");
String email = request.getParameter("email");
String password = request.getParameter("password");
User user = new User();
user.setUsername(userName);
user.setEmail(email);
user.setPassword(password);
UserDao userDao = new UserDao();
String userRegistered = userDao.registerUser(user);
if(userRegistered.equals("SUCCESS")){
request.getRequestDispatcher("test.jsp").forward(request, response);
}else{
request.setAttribute("error", userRegistered);
request.getRequestDispatcher("/UserRegistration.jsp").forward(request, response);
}
}
}
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Register</title>
<script>
function validate()
{
var username = document.form.username.value;
var email = document.form.email.value;
var password = document.form.password.value;
var conpassword= document.form.conpassword.value;
if (username==null || username=="")
{
alert("Full Name can't be blank");
return false;
}
else if (email==null || email=="")
{
alert("Email can't be blank");
return false;
}
else if(password.length<6)
{
alert("Password must be at least 6 characters long.");
return false;
}
else if (password!=conpassword)
{
alert("Confirm Password should match with the Password");
return false;
}
}
</script>
</head>
<body>
<center><h2>Java Registration application using MVC and MySQL </h2></center>
<form name="form" action="UserRegistrationServlet" method="post" onsubmit="return validate()">
<table align="center">
<tr>
<td>Username</td>
<td><input type="text" name="username" /></td>
</tr>
<tr>
<td>Email</td>
<td><input type="text" name="email" /></td>
</tr>
<tr>
<td>Password</td>
<td><input type="password" name="password" /></td>
</tr>
<tr>
<td>Confirm Password</td>
<td><input type="password" name="conpassword" /></td>
</tr>
<tr>
<td><%=(request.getAttribute("errMessage") == null) ? ""
: request.getAttribute("errMessage")%></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="Register"></input><input
type="reset" value="Reset"></input></td>
</tr>
</table>
</form>
</body>
</html>
不知道我的代碼中的錯誤在哪里,所以任何建議都會非常有幫助。 謝謝
更新:
[![拋出運行時異常后] [2]] [2]
您將user_id
設置為null
,並且數據庫抱怨該列不能為null
。 我假設您沒有直接將null
傳遞給您針對數據庫測試的語句,因此您設置了一個空字符串(或者表是設置默認值或自動生成的值,以防它丟失)。
如果有默認值或自動生成的值,您可以在insert語句中放棄user_id
,它應該可以工作。
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