checkid.java

音乐网站涉及到很多数据库查询

package serverBag;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

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

import publicBag.ConnectDB;

public class CheckID extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public CheckID() {
		super();
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @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 doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String returnMsg = "true";
		response.setContentType("text/xml");
		response.setHeader("Cache-Control","no-cache");
		PrintWriter out = response.getWriter();		
		request.setCharacterEncoding("GB2312");
		String userID = request.getParameter("userID").trim();
		try
        {
            Connection con = ConnectDB.connectMusicDB();
            PreparedStatement stat = con.prepareStatement("SELECT * FROM UserInfo WHERE cUserID=?");			
            stat.setString(1,userID);            
            ResultSet res = stat.executeQuery();
            if(res.next())
            {
                returnMsg = "false";
            }            		
        }
        catch(Exception e)
        {
            e.printStackTrace();
            returnMsg = "检测用户名失败！";
        }
        out.println("<reponse>");
		out.println("<msg>" + returnMsg + "</msg>");
		out.println("</reponse>");
		out.flush();
		out.close();
	}

	/**
	 * 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
	 */
	/* (non-Javadoc)
	 * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
	}

}