news.rar_jsp 新闻发布_jsp 新闻发布系统

package JavaBean; import java.math.*; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import DBOperation.DBConnection; /** * 简单的翻页获取数据，数据存在属性lst(ArrayList)中 * 需要继承类中的doSql()方法 * @author cjylove * */ public abstract class Paging { protected int currentPage = 1; //当前页 protected int totalRows = 0; //总数据条数 protected int totalPage = 0; //总页数 protected int rowsPerPage = 5; //每页的行数 protected Object firstOfPage; //当前页第一行数的编号 protected Object lastOfPage; //当前页最后一行数据的编号 protected String tableName; //查询数据的表名 protected String orderColunmName; //排序字段名 protected boolean hasCondition = false; //是否带有约束 public int getCurrentPage() { return currentPage; } public void setCurrentPage(int currentPage) { this.currentPage = currentPage; } public int getRowsPerPage() { return rowsPerPage; } public void setRowsPerPage(int rowsPerPage) { this.rowsPerPage = rowsPerPage; } public int getTotalPage() { double arg0 = (double)this.getTotalRows() / (double)this.getRowsPerPage(); this.totalPage = (int)Math.ceil(arg0); return totalPage; } public void setTotalPage(int totalPage) { this.totalPage = totalPage; } public Object getFirstOfPage() { return firstOfPage; } public void setFirstOfPage(Object firstOfPage) { this.firstOfPage = firstOfPage; } public Object getLastOfPage() { return lastOfPage; } public void setLastOfPage(Object lastOfPage) { this.lastOfPage = lastOfPage; } public String getTableName() { return tableName; } public void setTableName(String tableName) { this.tableName = tableName; } public String getOrderColunmName() { return orderColunmName; } public void setOrderColunmName(String orderColunmName) { this.orderColunmName = orderColunmName; } public int getTotalRows() { if(this.totalRows == 0) { try { ResultSet rs = db.sta.executeQuery("select count(*) from FirstLevelTitle"); int rows = 0; while(rs.next()){ rows = rs.getInt(1); } this.totalRows = rows; } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return totalRows; } public void setTotalRows(int maxRows) { this.totalRows = maxRows; } protected DBConnection db; //数据库操作类 protected ArrayList lst; //需要返回的数据 protected String SqlCondition = ""; /** * 不带SQL条件 * 需要参数：数据库名、表名、排序字段 * @param databaseName * @param tableName * @param orderColunmName */ public Paging(String databaseName,String tableName,String orderColunmName) { lst = new ArrayList(); db = new DBConnection(databaseName); this.tableName = tableName; this.orderColunmName = orderColunmName; } /** * 具有where条件语句 * @param databaseName * @param tableName * @param orderColunmName * @param SqlCondition */ public Paging(String databaseName,String tableName,String orderColunmName,String SqlCondition) { this(databaseName,tableName,orderColunmName); this.SqlCondition = SqlCondition; this.hasCondition = true; } /** * 获得当前页面的数据 * 只需传页码 * 和设置些其它属性 * @param page * @return */ public ArrayList getData(int page) { if(page==1) this.openPage(); else if(page - currentPage > 0) this.downPage(); else if(page - currentPage < 0) this.upPage(); return lst; } /** * 上翻一页 * */ public void upPage() { if(this.currentPage != 1) { String sql = null; if(this.hasCondition) { sql = "select * from (select top "+this.rowsPerPage +" * from (select * from "+this.tableName+" "+this.SqlCondition+ ") as b where "+this.orderColunmName+" < '"+this.firstOfPage+"' order by "+ this.orderColunmName+" desc) as c order by "+this.orderColunmName+" asc"; } else { sql = "select * from (select top "+this.rowsPerPage +" * from "+this.tableName+" where "+this.orderColunmName+" < '"+this.firstOfPage+"' order by "+ this.orderColunmName+" desc) as c order by "+this.orderColunmName+" asc"; } ResultSet rs = this.db.executeQuery(sql); this.doSql(rs); this.currentPage -= 1; } } /** * 下翻一页 * */ public void downPage() { if(this.currentPage != this.totalPage) { String sql = null; if(this.hasCondition) { sql = "select top "+this.rowsPerPage+ " * from (select * from "+this.tableName+" "+this.SqlCondition+ ") as c where "+this.orderColunmName+" > '"+this.lastOfPage+ "' order by "+this.orderColunmName+" asc"; } else { sql = "select top "+this.rowsPerPage+ " * from "+this.tableName+" where "+this.orderColunmName+ " > '"+this.lastOfPage+"' order by "+this.orderColunmName+" asc"; } ResultSet rs = this.db.executeQuery(sql); this.doSql(rs); this.currentPage += 1; } } /** * 打开第一页 * */ public void openPage() { String sql = null; if(this.hasCondition) { sql = "select top "+this.rowsPerPage+ " * from (select * from "+this.tableName+this.SqlCondition+ ") as c order by "+this.orderColunmName+" asc"; } else { sql = "select top "+this.rowsPerPage+" * from "+this.tableName +" order by "+this.orderColunmName+" asc"; } ResultSet rs = this.db.executeQuery(sql); this.doSql(rs); this.currentPage = 1; } /** * 从数据库获取数据，对应的实体类一一赋值 * 先将lst(ArrayList)清空 * 然后放入属性lst(ArrayList)中 * 最后对属性firstOfPage和lastOfPage分别将第一行数据和最后行数据的排序字段的值赋给 * * @param sql */ abstract public void doSql(ResultSet rs); }