我想从我的数据库中删除一行,但它不起作用。我有 2 个异常: - NumberFormatException:null(它用于 Servlet 中的 parseInt 部分) - PSQLException:错误:关系“患者”不存在......但它确实存在!你能帮我解决我的问题吗?
DB.java(只是方法)
public int deletePatient(int patID) {
try {
if (conn != null) {
String delete = "DELETE FROM \"Patients\" WHERE Patients.PatientID = ?";
PreparedStatement pstmt = conn.prepareStatement(delete);
pstmt.setInt(1, patID);
affectedRows = pstmt.executeUpdate();
} else {
System.out.println("Connection is not created! 5");
}
} catch (SQLException e) {
System.out.println(e.getMessage());
e.printStackTrace();
}
return affectedRows;
}
return affectedRows;
}
ServletP.java(只是方法)
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException, NumberFormatException {
try {
int patID = Integer.parseInt(request.getParameter("patID2"));
db.deletePatient(patID);
} catch (NumberFormatException n) {
n.printStackTrace();
}
PrintWriter writer = response.getWriter();
String htmlRespone = "<html>";
htmlRespone += "<h2>Action is done!</h2>";
htmlRespone += "<a href=\"/WebApp/patients\">Back</a>";
htmlRespone += "</html>";
writer.println(htmlRespone);
}
jsp:
<div>
<form method="POST" action="patients">
<table border="2" align="center">
<tr>
<td>ID:</td>
<td><input type="text" name="patID2"></td>
<td><input type="submit" value="Delete"></td>
</tr>
</table>
</form>
</div>