Question

点击提交按钮

时出现异常

我的所有代码都运行良好，但是当我添加上传图片的代码时那么这个错误就会发生

在这些位置我完成了更改 1.在html中 enctype =＆＃34; multipart / form-data＆＃34; 新添加 2.在jsp中添加了项目derectory中的保存图像

给我一些解决方案......

com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException：Column＆＃39; name＆＃39;不能为空

我的HTML格式

<form method="post" enctype="multipart/form-data" >
    <div class="intro"> 
  <h1>Setup your Details</h1>
  <h2></h2>
</div>
<%
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = 
DriverManager.getConnection("jdbc:mysql://localhost:3306/slambook","root", 
 "");
Statement st = con.createStatement();
String user = (String) session.getAttribute("userid");
String qry = "select * from userdetails where `userid`='"+user+"'";
ResultSet result = st.executeQuery(qry);

while(result.next()){
//id = result.getInt("id");   

%>     
<input type="text" placeholder="Name" name="name" value="<%=result.getString("name")%>" required/>
<input type="number" placeholder="Contact No." name="cno" value="<%=result.getString("cno")%>" required/>
Choose File : <input type="file" name="file" required>
<textarea placeholder="Address" name="address" rows="4"><%=result.getString("address")%></textarea>
<input type="date" name="dob" value="<%=result.getString("dob")%>"/>
<input type="text" placeholder="Dream" name="dream" value="<%=result.getString("dream")%>" required/>
<input type="text" placeholder="Favorite Personality" name="favperson" value="<%=result.getString("favperson")%>" required/>
<input type="text" placeholder="Secret Crush" name="crush" value="<%=result.getString("crush")%>"/>

<%if(result.getString("userid").equals(null))
    {
        %><input type="submit" name="btnsave" value="Save Details" onclick="form.action='saveuserdetails.jsp';"/>
        <input type="submit" name="btnupdate" value="update Details" onclick="form.action='updateuserdetails.jsp';"/>
        <input type="reset" value="Clear" style="float: right;"><%
    }
    else
    {%>
        <input type="submit" name="btnupdate" value="update Details" onclick="form.action='updateuserdetails.jsp';"/>
        <input type="reset" value="Clear" style="float: right;"><%
    }

}  
}
catch(Exception ex)
{
    out.println(ex);
}
%>

这是我的更新jsp

    <%@page import="java.io.*"%>
   <%@ page import ="java.sql.*,java.io.*,java.util.*" %>
   <%
    String uid = (String) session.getAttribute("userid");
   String name = request.getParameter("name");    
   String cno = request.getParameter("cno");
   //String picaddress = request.getParameter("file");
     String address= request.getParameter("address");
  String dob= request.getParameter("dob");
  String dream= request.getParameter("dream");
  String favperson= request.getParameter("favperson");
  String crush= request.getParameter("crush");

  String saveFile = ""; 
  String contentType = request.getContentType();
  if((contentType != null)&&(contentType.indexOf("multipart/form-data")>=0))
  {
    DataInputStream in = new DataInputStream(request.getInputStream());
    int formDataLength = request.getContentLength();
    byte dataBytes[] = new byte[formDataLength];
    int byteRead = 0;
    int totalBytesRead = 0; 
    while(totalBytesRead < formDataLength)
    {
        byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
        totalBytesRead +=byteRead;
    }
    String file = new String(dataBytes);
    saveFile = file.substring(file.indexOf("filename=\"")+10);
    saveFile = saveFile.substring(0,saveFile.indexOf("\n"));
    saveFile = 
    saveFile.substring(saveFile.lastIndexOf("\\")+1,saveFile.indexOf("\""));
    int lastIndex = contentType.lastIndexOf("=");
    String boundry = contentType.substring(lastIndex 
  +1,contentType.length());
    int pos;
    pos = file.indexOf("filename=\"");
    pos = file.indexOf("\n",pos)+1;
    pos = file.indexOf("\n",pos)+1;
    pos = file.indexOf("\n",pos)+1;
    int boundryLocation = file.indexOf(boundry,pos)-4;
    int startPos = ((file.substring(0,pos)).getBytes()).length;
    int endPos = ((file.substring(0, boundryLocation)).getBytes()).length;
     File ff =new File("C:/Users/Jarvis/Documents/NetBeansProjects/Slambook/web/ProfileImages/"+saveFile);
    FileOutputStream fileOut = new FileOutputStream(ff);
    fileOut.write(dataBytes,startPos,(endPos-startPos));
    fileOut.flush();
    fileOut.close();


  try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = 
  DriverManager.getConnection("jdbc:mysql://localhost:3306/slambook",
        "root", "");
out.println(address);
PreparedStatement ps = con.prepareStatement("update userdetails set name =?,cno = ?, address = ?,dob = ?,dream = ?,favperson = ?,crush = ?,imgstream = ? where userid = ?");
ps.setString(9, uid);
ps.setString(1, name);
ps.setString(2, cno);

ps.setString(3, address);
ps.setString(4, dob);
ps.setString(5, dream);
ps.setString(6, favperson);
ps.setString(7, crush);
ps.setString(8,ff.getPath());
ps.executeUpdate();
response.sendRedirect("userdetails.jsp");
 }
  catch(Exception e)
  {
  out.println(e);
  }
  }
%>

Answer 1

为了捕获特定的SQLException，需要使用getSQLState（）方法与SQl State进行比较。例如：SQl State 23用于数据完整性违规。

          `catch (SQLException ex) {
                if (ex.getSQLState().startsWith("23")) {
                      JOptionPane.showMessageDialog(null, "Duplicate");
                } 
          }`

Found from here

从request.getparameter获取null值（＆＃34; name＆＃34;）; com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException

1 个答案: