为什么删除语句不起作用?
为什么
String sql="DELETE FROM qx where qx_yonghuming='"+d_first+'"';
String sql="DELETE FROM qx where qx_yonghuming='aa'";
都不起作用?
文件1 shanchu.jsp
<%@ page contentType="text/html;charset=GBK" %>
<%@ page language="java" import="java.sql.*" %>
<jsp:useBean id="connDb" scope="page" class="quanxian_db.ConnOracle"/>
<%
String d_first=request.getParameter("text_shanchuyonghu").trim();
String d_second=request.getParameter("text_reshanchuyonghu").trim();
out.println(d_first);
out.println(d_second);
if (d_first.trim() == d_second.trim()) {
String sql="DELETE FROM qx where qx_yonghuming='"+d_first+'"';
String sql="DELETE FROM qx where qx_yonghuming='aa'";
connDb.executeUpdate(sql);
}
else{
out.println("两次输入用户名不一致!");
}
%>
用于连接数据库的javabean:
package quanxian_db;
import java.sql.*;
public class ConnOracle {
String sDBDiver="sun.jdbc.odbc.JdbcOdbcDriver";
Connection connect=null;
//Statement stmt;
ResultSet rs=null;
public ConnOracle(){
try{
Class.forName(sDBDiver);
}
catch(java.lang.ClassNotFoundException e){
System.err.println(e.getMessage());
}
}
public ResultSet executeQuery(String sql){
try{
connect=DriverManager.getConnection("jdbc:odbc:quanxian","system","pass");
Statement stmt=connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs=stmt.executeQuery(sql);
}
catch(SQLException ex){
System.err.println(ex.getMessage());
}
return rs;
}
public int executeUpdate(String sql){
int result=0;
try{
connect=DriverManager.getConnection("jdbc:odbc:quanxian","system","pass");
Statement stmt=connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
result=stmt.executeUpdate(sql);
}
catch(SQLException ex){
System.err.println(ex.getMessage());
}
return result;
}
}
用于调用shanchu文件的页面的一部分:
<form action="shanchu.jsp" method="post" >
<table width="65%" border="0" align="center" bgcolor="#99CCFF">
<tr>
<td width="14%" align="left"><strong>删除用户</strong></td>
<td width="30%" align="left"><font color="#000000"><b>输入用户名</b></font><font><b>
<input name="text_shanchuyonghu" type="text" size=15>
</b></font></td>
<td width="31%" align="left"><font color="#ff0033"><b><font color="#000000">确认输入</font>
<input name="text_reshanchuyonghu" type="text" size=15>
</b></font></td>
<td width="11%" align="center">
<input type="submit" name="Submit" value=" 删 除 " >
</td>
</tr>
</table>
</form>