validate.java

JAVA的MVC三层开发的图书馆管理系统。

package mypackage;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.PrintWriter;
import java.io.IOException;
import java.sql.*;
import javax.sql.DataSource;

public class Validate extends HttpServlet 
{
  private static final String CONTENT_TYPE = "text/html; charset=GBK";

  public void init(ServletConfig config) throws ServletException
  {
    super.init(config);
  }

  public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    response.setContentType(CONTENT_TYPE);
    String username = request.getParameter("username");
    String password = request.getParameter("password");
    String pwd = null;
    DataSource ds = (DataSource)request.getSession().getServletContext().getAttribute("DataSrc");
    String sql = "select * from admin where username = '"+username+"'";
    
    try{
      Connection conn = ds.getConnection();
      Statement stmt = conn.createStatement();
      ResultSet rs = stmt.executeQuery(sql);
      if(rs.next())
        pwd = rs.getString("password");
      rs.close();
      stmt.close();
      conn.close();
    }
    catch(Exception e){
      System.out.println(e.getMessage());  
    }
    
    if(password.equals(pwd))
      request.getSession().setAttribute("validate","pass");
    request.getSession().getServletContext().getRequestDispatcher("/index.jsp").forward(request,response);
  }
}