select_menu.jsp

多级联动菜单 用Ajax和 javas实现的

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ page import="java.sql.*, ajax.db.DBUtils"%>
<%!
	String getOptions(String selectedId)
	{
		int counter=0;
		StringBuffer opts = new StringBuffer("{");
		
		//定义查询数据库的SQL语句。
		String sql = "select * from select_menu where pid = ? order by seq asc";
		
		Connection conn = null;
		PreparedStatement pstmt=null;
		ResultSet rs=null;
		
		try
		{
			conn = DBUtils.getConnection();
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1,selectedId) ;
			rs = pstmt.executeQuery();
			while(rs.next())
			{
				if(counter>0)
				{
					opts.append(",");
				}
				opts.append("'");
				opts.append(rs.getString("id"));
				opts.append("':'");
				opts.append(rs.getString("text"));
				opts.append("'");
				//大体格式是 {'id : text','id2 : text2'},
				counter++;
				 
			}
		}
		catch(SQLException se)
		{
			System.out.println(se.getMessage());
		}
		finally
		{
			DBUtils.close(rs);
			DBUtils.close(pstmt);
			DBUtils.close(conn);
		}
		opts.append("}");
		return opts.toString();
	}
 %>
 <%
 	out.clear();
 	
 	String selectedId = request.getParameter("selectedId");
 	
 	System.out.println(selectedId);
 	String optionsinfo=getOptions(selectedId);
 	System.out.println(optionsinfo);
 	out.println(optionsinfo);
 	
  %>