photolistservlet.java

一些数据库的java开发编程

package jdbcbook.photo;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;

import jdbcbook.pub.util.*;

/**
 * 显示照片列表Servlet
 */
public class PhotoListServlet extends HttpServlet
{

	public void doPost(HttpServletRequest request, HttpServletResponse response)
						throws IOException, ServletException
	{
		// 得到照片类别信息
		int nCategoryid = RequestUtil.getInt( request, "categoryid", 0 );

		// 得到所有的照片分类信息
		Collection categorys = CategoryBean.queryCategory( null );
		request.setAttribute( "categorys", categorys );

		if( nCategoryid <= 0 )
		{
			// 如果传递的照片类别信息不对，则取第一个照片分类为默认照片分类
			Iterator it = categorys.iterator();
			if( it.hasNext() )
				nCategoryid = ( (Category)it.next() ).getCategoryid();
		}
		
		if( nCategoryid <= 0 )
		{
			// 照片分类信息不正确，则设置提示信息，跳转到照片分类信息列表Servelet
			RequestUtil.setMsg( this, request, "categoryfirst" );
			RequestDispatcher dispatcher = request.getRequestDispatcher( "categorylist" );
			dispatcher.forward( request, response );
		}
		// 得到照片分类的照片信息
		Collection photos = PhotoBean.getPhotos( nCategoryid );
		request.setAttribute( "photos", photos );
		request.setAttribute( "categoryid", nCategoryid );

		// 跳转到照片列表页面
		RequestDispatcher dispatcher = request.getRequestDispatcher( "photo_list.vm" );
		dispatcher.forward( request, response );
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
						throws IOException, ServletException
	{
		doPost( request, response );
	}
}