addcomment.java

书店实现用struts实现的一个系统 采用mysql数据库

/**
 * 该Servlet用于添加图书评论
 */
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import bean.DBClass;

public class AddComment extends HttpServlet{
	public void doGet(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException{
		int i=0;
		String id="";
		String userId="";
		request.setCharacterEncoding("gb2312");
		String bookId=request.getParameter("bookId");
		String stars=request.getParameter("stars");
		String comment=request.getParameter("comment");
		String toJsp="/bookshop/bookComment.jsp?bookId="+bookId;
		HttpSession session=request.getSession();
		if(session.getAttribute("userId")==null){
			userId="游客";
		}else{
			userId=(String)session.getAttribute("userId");
		}
		String query="SELECT id FROM bookcomment";
		DBClass db=new DBClass();
		db.connect();
		ResultSet resultset=db.executeQuery(query);
	try{
	
		/* 为添加的图书评论设置id号 */
		while(resultset.next()){
        	id=resultset.getString("id");
        	i=Integer.parseInt(id);
        	i++;
		}
		id=Integer.toString(i);
		
		 /* 添加图书评论 */
		String command="INSERT INTO bookcomment VALUES("
			              + "\'"+ id + "\'"+ ","
			              + "\'"+ bookId + "\'"+ ","
			              + "\'"+ userId + "\'"+ "," 
			              + "\'"+ comment + "\'"+ ","
			              + "\'"+ stars + "\'"+ ")";
	    db.executeUpdate(command);
	    db.closeConnection();
	    }catch(SQLException sqle){
			    System.err.println("Erro with connection:"+sqle);
		}
	    response.sendRedirect(toJsp);
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response) 
	throws ServletException, IOException {
		doGet(request, response);
	}
}