以下是我的错误的地方(全部代码在附件里)
我引用的的方法原体是
public ResultSet executeQuery(String sql) throws Exception
{ try
{
Class.forName(driverClass);
conn=DriverManager.getConnection(url,username,password);
Statement stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
}
catch(SQLException ex)
{
System.err.println("sql_data.executeQuery:"+ex.getMessage());
}
return rs;
}
具体实现的核心是
<%
Sql mysql=new Sql();
ResultSet rs=mysql.executeQuery("select sno from student");
while(rs.next()){
//out.println(""+rs.getInt(1)+"");
} %>
出错信息如下
org.apache.jasper.JasperException: An exception occurred processing JSP page /MyJsp.jsp at line 2724: <%
25: Sql mysql=new Sql();
26: mysql.executeQuery("select sno from student");
27: while(rs.next()){
28: //out.println(""+rs.getInt(1)+"");
29:
30: } %>本人菜鸟,望各位大虾赐教!!
我引用的的方法原体是
public ResultSet executeQuery(String sql) throws Exception
{ try
{
Class.forName(driverClass);
conn=DriverManager.getConnection(url,username,password);
Statement stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
}
catch(SQLException ex)
{
System.err.println("sql_data.executeQuery:"+ex.getMessage());
}
return rs;
}
具体实现的核心是
<%
Sql mysql=new Sql();
ResultSet rs=mysql.executeQuery("select sno from student");
while(rs.next()){
//out.println(""+rs.getInt(1)+"");
} %>
出错信息如下
org.apache.jasper.JasperException: An exception occurred processing JSP page /MyJsp.jsp at line 2724: <%
25: Sql mysql=new Sql();
26: mysql.executeQuery("select sno from student");
27: while(rs.next()){
28: //out.println(""+rs.getInt(1)+"");
29:
30: } %>本人菜鸟,望各位大虾赐教!!
ResultSet rs=pstmt.executeQuery();
至于Class.forName(driverClass).newInstance()、select * 以及PreparedStatement与Statement对应用性能上的影响、sql语句中"?"号与实际参数在安全上的影响等LZ在以后的学习中再去关注吧。