Access使用PreparedStatement报出java.lang.NullPointerException

Question

import java.sql.*;public class PreStmt
{
    public static void main(String args[])
    {
         try
        {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            Connection conn=DriverManager.getConnection("jdbc:odbc:taobao");
            String sql = "insert into 123(a2,a3,a4) values('?','?','?')";
            PreparedStatement stmt = conn.prepareStatement(sql);
            conn.setAutoCommit(false);
            stmt.setString(1,"abcdefg");
            stmt.setString(2,"abcdefg");
            stmt.setString(2,"abcdefg");
            System.out.println(stmt);
            stmt.execute(sql);
            stmt.close();
            conn.commit();
            conn.close();
            System.out.println("success");
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}在Access中直接运行SQL语句insert into 123(a2,a3,a4) values('?','?','?')能够插入JAVA中报出
java.lang.NullPointerException
        at sun.jdbc.odbc.JdbcOdbcPreparedStatement.clearParameter(JdbcOdbcPreparedStatement.java:1023)
        at sun.jdbc.odbc.JdbcOdbcPreparedStatement.setChar(JdbcOdbcPreparedStatement.java:3057)
        at sun.jdbc.odbc.JdbcOdbcPreparedStatement.setString(JdbcOdbcPreparedStatement.java:766)
        at CsvtoDb.PreStmt.main(PreStmt.java:26)
百思不得其解。求高人。

Answer 1

PreparedStatement stmt = conn.prepareStatement(sql);
  conn.setAutoCommit(false);
  stmt.setString(1,"abcdefg");
  stmt.setString(2,"abcdefg");
  stmt.setString(2,"abcdefg");
  System.out.println(stmt);
  stmt.execute(sql);
-》stmt.executeUpdate();

Answer 2

ls真快啊。ls已经告诉你错误原因了。
lz分析下root cause看看是你代码具体哪行就知道了，以后这样的错误就知道如何找了。

Answer 3

 stmt.setString(1,"abcdefg");
  stmt.setString(2,"abcdefg");
  stmt.setString(2,"abcdefg");
改成 stmt.setString(1,"abcdefg");
  stmt.setString(2,"abcdefg");
  stmt.setString(3,"abcdefg");

Answer 4

不是这个问题。即使改成stmt.setString(1,"abcdefg");
stmt.setString(2,"abcdefg");
stmt.setString(3,"abcdefg");还是一样出错。
运行到stmt.setString(1,"abcdefg");就报错停止了。
实在头大

Answer 5

at sun.jdbc.odbc.JdbcOdbcPreparedStatement.setString(JdbcOdbcPreparedStatement.java:766)