newsmgr.java

新闻发布系统的雏形

package com.kjlm.beans;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collection;

public class NewsMgr {
	Connection conn = null;

	Statement stmt = null;

	ResultSet rs = null;

	public Boolean exist(News news) {
		// TODO Auto-generated method stub
		Boolean flag = false;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://localhost/news?user=root&password=3819568";
			conn = DriverManager.getConnection(url);
			stmt = conn.createStatement();
			String title = news.getTitle();
			String sql = "select * from news where title ='" + title + "'";
			ResultSet rs = stmt.executeQuery(sql);
			if (rs.next()) {
				flag = true;
			}
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	public void insert(News news) {
		// TODO Auto-generated method stub
		try {
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://localhost/news?user=root&password=3819568";
			conn = DriverManager.getConnection(url);
			stmt = conn.createStatement();
			String title = news.getTitle();
			String content = news.getContent();
			int categoryId = news.getCategoryId();

			String sql = "insert into news values(null,'" + title + "','"
					+ content + "','" + categoryId + "',now() )";
			stmt.executeUpdate(sql);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}

	public int getCount(int categoryId) {
		int count = 0;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://localhost/news?user=root&password=3819568";
			conn = DriverManager.getConnection(url);
			stmt = conn.createStatement();
			String sql = "select count(*) from news where categoryId = "
					+ categoryId ;
			ResultSet rs = stmt.executeQuery(sql);
			if (rs.next()) {
				count = rs.getInt(1);
			}
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		return count;
	}

	public Collection getAllNewsByCategoryId(int page, int pageSize,
			int categoryId, int pageTotalNum) {
		Collection<News> c = new ArrayList<News>();

		try {
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://localhost/news?user=root&password=3819568";
			conn = DriverManager.getConnection(url);
			stmt = conn.createStatement();
//			String sql = "select * from news limit " + (page - 1) * pageSize
//					+ "," + pageSize + " where category = '" + categoryName
//					+ "'";
			if(page>pageTotalNum){
				page =pageTotalNum;
			}
			String sql = "select * from news where categoryId = " + categoryId + " limit " + (page-1)*pageSize
			+ "," + pageSize;
			ResultSet rs = stmt.executeQuery(sql);
			News news = null;
			while (rs.next()) {
				news = new News();
				news.setId(rs.getInt("id"));
				news.setTitle(rs.getString("title"));
				news.setContent(rs.getString("content"));
				news.setCategoryId(categoryId);
				c.add(news);
				news = null;
			}
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		return c;
	}

}