数据库小问题

代码：
<%@ page contentType="text/html;charset=GB2312"%>
<%@ page import="java.sql.*"%>
<html>
<body>
<%
 Connection con;
 Statement sql;
 ResultSet rs;
 try{Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
   }
   catch(ClassNotFoundException e){} con=DriverManager.getConnection("jdbc:odbc:sun","sa","");
 sql=con.createStatement();
 rs=sql.executeQuery("select * from user");
 while(rs.next())
 {
  out.print(rs.getString(1));
  out.print(rs.getString(2));
  out.print(rs.getString(3));
  }
  con.close();
  }
  catch(SQLException e1){}
  %>
  </body>
  </html>
报错：
org.apache.jasper.JasperException: Unable to compile class for JSP: Stacktrace:
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:85)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:415)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:308)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:308)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.10 logs.

解决方案 »

  1.   

    try{Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
       }
       catch(ClassNotFoundException e){}
    //这里缺了try了...或者整合到前面那个try catch块中去
    try { con=DriverManager.getConnection("jdbc:odbc:sun","sa","");
     sql=con.createStatement();
     rs=sql.executeQuery("select * from user");
     while(rs.next())
     {
      out.print(rs.getString(1));
      out.print(rs.getString(2));
      out.print(rs.getString(3));
      }
      con.close();
      }
      catch(SQLException e1){}
      

  2.   


    try{//try上也不行吗？
     con=DriverManager.getConnection("jdbc:odbc:sun","sa","");
     sql=con.createStatement();
     rs=sql.executeQuery("select * from user");
     while(rs.next())
     {
      out.print(rs.getString(1));
      out.print(rs.getString(2));
      out.print(rs.getString(3));
      }
      con.close();
      }//我也觉得是这里的问题
      catch(SQLException e1){}
      

  3.   

    <%@ page contentType="text/html;charset=GB2312"%>
    <%@ page import="java.sql.*"%>
    <html>
    <body>
    <%
     Connection con;
     Statement sql;
     ResultSet rs;
     try{
         Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        con=DriverManager.getConnection("jdbc:odbc:sun","sa","");
     sql=con.createStatement();
     rs=sql.executeQuery("select * from user");
     while(rs.next())
     {
      out.print(rs.getString(1));
      out.print(rs.getString(2));
      out.print(rs.getString(3));
      }
      con.close();
      }
      catch(Exception e){}
      %>
      </body>
      </html>
    这样吧，我编译通过了，应该是try，catch的问题但是这里可能会有多个异常，ClassNotFoundException和SQLException，所以楼上的只捕捉SQLException是不够的，可以直接写上Exception，就都捕捉了，如果知道是几个异常就可以分别catch
      

  4.   

    <%@ page contentType="text/html;charset=GB2312"%>
    <%@ page import="java.sql.*"%>
    <html>
    <body>
    <%
     Connection con;
     Statement sql;
     ResultSet rs;
     try{Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
       }
       catch(ClassNotFoundException e){}try{
     con=DriverManager.getConnection("jdbc:odbc:sun","sa","");
     sql=con.createStatement();
     rs=sql.executeQuery("select * from user");
     while(rs.next())
     {
      out.print(rs.getString(1));
      out.print(rs.getString(2));
      out.print(rs.getString(3));
      }  }
      catch(SQLException e1){}
    finally{
    rs.close();
    sql.close();
    con.close();
    }
      %>
      </body>
      </html>