抛出空指针异常&我不明白为什么这样 [英] Throws Null pointer Exception & i'm not getting why this so

问题描述

我有以下代码&我通过jsp页面调用它，但它在这一行给我

NullPointerException

i am having the following code & i'm calling it through the jsp page but it giving me the
NullPointerException at this line

cs.setDate(6,(Date)df.parse(ptechdatabean.getFrom_Date()));

因为im使用java，jsp，jdbc，oracle 10g可以有人告诉我为什么会这样....

as i m using java, jsp, jdbc, oracle 10g can someone tell me why this is so....

package Ptech;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Types;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.sql.Date;

public class User_Master_procedure {

    public ArrayList Call_User_Master_procedure(PtechDataBean ptechdatabean) throws ClassNotFoundException, SQLException, ParseException {

        DateFormat df = new SimpleDateFormat("MM/dd/yyyy"); 
        DatabaseConnection db = new DatabaseConnection();
        Connection Connect = db.Oracle_Connect();
        CallableStatement cs = Connect.prepareCall("{call Pr_User_Master_Insert(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)}");
        cs.setString(1, ptechdatabean.getCompany_id());
        cs.setString(2, ptechdatabean.getBranch_id());
        cs.setString(3, ptechdatabean.getUser_id());
        cs.setString(4, ptechdatabean.getName());
        cs.setString(5, ptechdatabean.getPassword());
        cs.setDate(6,(Date)df.parse(ptechdatabean.getFrom_Date()));
        cs.setDate(7,(Date)df.parse(ptechdatabean.getTo_Date()));
        cs.setString(8,ptechdatabean.getStatus());
        cs.setInt(9, ptechdatabean.getEntered_By());
        cs.setDate(10,(Date)df.parse(ptechdatabean.getEntered_Date()));
        cs.setInt(11, ptechdatabean.getUpdated_By());
        cs.setDate(12, (Date)df.parse(ptechdatabean.getUpdate_Date()));
        cs.setString(13, ptechdatabean.getIp_Address());
        cs.setString(14, ptechdatabean.getMac_Address());
        cs.setString(15, ptechdatabean.getCard_Id());
        cs.setString(16, ptechdatabean.getUser_Name());
        cs.setString(17, ptechdatabean.getFlag());
        cs.registerOutParameter(18, Types.VARCHAR);
        cs.registerOutParameter(19, Types.VARCHAR);
        cs.executeUpdate();
        Connect.commit();
        ArrayList al = new ArrayList();
        {
            al.add(cs.getString(18));
            al.add(cs.getString(19));
        }

        return al;
    }
}

推荐答案

您可能无法解析日期。



请多加一行并检查格式。

最好保持默认格式：

You are probably failing at parsing the date.

Please make that an extra line and check the format.
It's probably best to keep it to the default format:

DateFormat df = new SimpleDateFormat();//"MM/dd/yyyy"); 

// otherCode();

String dateValue = ptechdatabean.getFrom_Date();
Date date = df.parse(dateValue);
cs.setDate(6, date);

确保你的字段'尝试来自包含您正在格式化的格式的日期。如果date字段为null，则抛出NullPointerException，否则抛出ParseException。在你的情况下，我认为你的bean没有传递日期，检查你的代码抽象，看看问题到底在哪里然后尝试以下。

Ensure that the field you're trying to get from contains a date in the format you are formatting. If the date field is null, the NullPointerException is thrown, otherwise it throws the ParseException. In your case, I think your bean is not passing the date, check your code abstraction to see where the problem really is and then try the following.

DateFormat df = new SimpleDateFormat("MM/dd/yyyy");
// You don't have to cast to Date as the returned value is already formatted as a date.
cs.setDate(6, df.parse(ptechdatabean.getFrom_Date());

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