新闻项目封装

DBHelper类：

package com.zking.util;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class DBHelper {
	private static String user = "scott";
	private static String upwd = "tiger";
	private static String cname = "oracle.jdbc.driver.OracleDriver";
	private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
	
	//注册驱动类
	static {
		try {
			Class.forName(cname);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	//连接数据库
	/**
	 * 连接数据库
	 * @return
	 */
	public static Connection getCon() {
		Connection con = null;
		try {
			con = DriverManager.getConnection(url, user, upwd);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return con;
	}
	
	/**
	 * 关闭连接
	 * @param con
	 * @param ps
	 * @param rs
	 */
	public static void closeDb(Connection con,PreparedStatement ps,ResultSet rs) {
		try {
			if(con!=null) {
				con.close();
			}
			if(ps!=null) {
				ps.close();
			}
			if(rs!=null) {
				rs.close();
			}
			
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * 下一个获取下一个编号的方法
	 * @return 下一个编号
	 */
	public static int getNextId(String tableName,String col) {
		int id = 1;
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("select max("+col+") from "+tableName);
			rs = ps.executeQuery();
			if(rs.next()) {
				id = rs.getInt(1)+1;
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, rs);
		}
		return id;
	}
	
	
	//关闭连接

}

dao类：

NesDao：新闻的增删改查方法

package com.zking.dao;

import java.sql.Connection;

import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;

import com.zking.entity.News;
import com.zking.util.DBHelper;

public class NewsDao {
	//添加新闻
	/**
	 * 添加新闻
	 * @param news 要添加的新闻对象
	 * @return 成功返回1，失败返回0
	 */
	public int addNews(News news) {
		int i = 0;
		Connection con = null;
		PreparedStatement ps = null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("insert into news(nid,tid,ntitle,nzz,ncontent,nzy,ndate,nlook) values(?,?,?,?,?,?,sysdate,0)");
			ps.setInt(1, DBHelper.getNextId("news", "nid"));
			
			ps.setInt(2, news.getTid());
			ps.setString(3, news.getNtitle());
			ps.setString(4, news.getNzz());
			ps.setString(5, news.getNnr());
			ps.setString(6, news.getNzy());
			i = ps.executeUpdate();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, null);
		}
		return i;
	}
	//删除新闻
	/**
	 * 删除新闻
	 *  @param nid 要删除的新闻编号
	 * @return 成功返回1，失败返回0
	 */
	public int delete(int nid) {
		int i = 0;
		Connection con = null;
		PreparedStatement ps = null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("delete news where nid="+nid);
			i = ps.executeUpdate();
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, null);
		}
		return i;
	}
	
	//修改新闻
	/**
	 * 修改新闻
	 * @param nid 要修改的 新闻编号
	 * @param news 修改后的新闻
	 * @return 成功返回1，失败返回0
	 */
	public int upNews(int nid,News news) {
		int i = 0;
		Connection con = null;
		PreparedStatement ps = null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("update news set tid=?,ntitle=?,nzz=?,ncontent=?,nzy=? where nid="+nid);
			ps.setInt(1, news.getTid());
			ps.setString(2, news.getNtitle());
			ps.setString(3, news.getNzz());
			ps.setString(4, news.getNnr());
			ps.setString(5, news.getNzy());
			i = ps.executeUpdate();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, null);
		}
		return i;
	}
	
	
	//分页查询：
	/**
	 * 分页查询
	 * @param pageIndex 页码
	 * @param pageSize 每页数据条数
	 * @return 范湖查询到的集合
	 */
	public ArrayList<News> pageNews(int pageIndex,int pageSize){
		ArrayList<News> nlist = new ArrayList<>();
		int start = (pageIndex-1)*pageSize+1;
		int end = pageIndex*pageSize;
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			con = DBHelper.getCon();
			String sql = "select * from(select a.*,rownum mid from news a)b where mid>=? and mid<=?";
			ps = con.prepareStatement(sql);
			ps.setInt(1, start);
			ps.setInt(2, end);
			
			rs = ps.executeQuery();
			while(rs.next()) {
				int nid = rs.getInt(1);
				int tid = rs.getInt(2);
				String nzz = rs.getString(4);
				String ntitle = rs.getString(3);
				String nnr = rs.getString(5);
				Date ndate = rs.getDate(6);
				int nlook = rs.getInt(7);
				String nzy = rs.getString(8);
				String nimage = rs.getString(9);
				
				//实例化对象
				News news = new News(nid, tid, ntitle, nzz, nnr, nzy, ndate, nlook, nimage);
				//把新闻对象放到集合中
				nlist.add(news);
			}
			
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, rs);
		}
		
		return nlist;
	}
	
	//最大页码方法
	/**
	 * 求出最大也，啊
	 * @param pageSize 每页数据条数
	 * @return 返回最大页码
	 */
	public int getMaxPage(int pageSize) {
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		int maxPage = 0;
		int count = 0;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("select count(*) from news");
			rs = ps.executeQuery();
			if(rs.next()) {
				count = rs.getInt(1);
				maxPage = count/pageSize;
				if(count%pageSize!=0) {
					maxPage++;
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, rs);
		}
		return maxPage;
	}
	
	
	//模糊查询
	//分页模糊查询
	//。。。。

}

  userDao类：用户登陆与用户注册

package com.zking.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.zking.entity.User;
import com.zking.util.DBHelper;

public class UserDao {
	//用户登录-根据帐号 密码 进行查询
	/**
	 * 用户登录
	 * @param uname 用户名
	 * @param upwd 用户密码
	 * @return 登录成功返回用户对象，失败返回null
	 */
	public User login(String uname,String upwd) {
		User user = null;
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs= null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("select * from T277 where uname=? and upwd=?");
			ps.setString(1, uname);
			ps.setString(2, upwd);
			rs = ps.executeQuery();
			//操作数据
			if(rs.next()) {
				int uuid = rs.getInt(1);
				String uinfo = rs.getString(4);
				
				user = new User(uuid, uname, upwd, uinfo);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			
			DBHelper.closeDb(con, ps, rs);
		}
		return user;
	}
	/**
	 * 用户注册
	 * @param user 注册的用户对象
	 * @return
	 */
	public int register(User user) {
		int i = 0;
		Connection con = null;
		PreparedStatement ps = null;
		try {
			con = DBHelper.getCon();
			ps = con.prepareStatement("insert into T277 values(?,?,?,?)");
			ps.setInt(1, DBHelper.getNextId("T277","uuid"));
			ps.setString(2, user.getUname());
			ps.setString(3, user.getUpwd());
			ps.setString(4, user.getUinfo());
			i = ps.executeUpdate();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.closeDb(con, ps, null);
		}
		return i;
	}
	
}