query.java

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package Servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Vector;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import Bean.GetStudent;

public class query extends HttpServlet {

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html; charset=gb2312");
		PrintWriter out = response.getWriter();
		String studentId=request.getParameter("studentId");
		String studentSex="";
		String sql="select * from student";
		if(studentId==null)
		{
			studentSex=request.getParameter("studentSex");
			if(studentSex!=null)
			{
				studentSex=new String(studentSex.getBytes("iso8859-1"),"gb2312");
				sql=sql+" where studentSex='"+studentSex+"'";
			}
		}
		else
		{
			sql=sql+" where studentId='"+studentId+"'";
		}
		System.out.println(sql);
		Vector vec=new Vector();
		try {
			vec=(new GetStudent()).getData(sql);
		} catch (Exception e) {
			e.printStackTrace();
		}
		String msg="";
		String file="";
		if(vec.size()==0)
		{
			msg="没有相应的数据！";
			request.setAttribute("msg", msg);
			file="condition.jsp";
		}
		else
		{
			
			request.setAttribute("vec", vec);
			if(studentId==null && studentSex==null)
				file="result.jsp";
			if(studentId==null)
				file="result.jsp";
			else
				file="update.jsp";
		}
		RequestDispatcher rd=request.getRequestDispatcher(file);
		rd.forward(request, response);
		
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

	protected void doGet(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(arg0, arg1);
	}

}