Java编程琐事（7）——封装JDBC分页
一、编写一个接口从ResultSet继承：
package com.solid.test;
import java.sql.ResultSet;
import java.sql.SQLException;
public interface Pageable extends ResultSet {
//返回总页数
int getPageCount();
//返回当前页的记录条数
int getPageRowsCount();
//返回分页大小
int getPageSize();
//转到指定页
void gotoPage(int page);
//设置分页大小
void setPageSize(int pageSize);
//返回总记录行数
int getRowsCount();
//转到当前页的第一条记录
void pageFirst() throws SQLException;
//转到当前页的最后一条记录
void pageLast() throws SQLException;
//返回当前页号
int getCurrentPageNo();
}
二、编写实现接口的方法：
public class PageableResultSet implements Pageable {
protected ResultSet rs=null;
//每页行数
protected int rowsCount;
//分页大小
protected int pageSize;
//当前页号
protected int currentPageNo;
protected String command = "";
//构造方法
public PageableResultSet(ResultSet rs) throws java.sql.SQLException {
if(rs==null) throw new SQLException("given ResultSet is NULL","user");
rs.last();
rowsCount=rs.getRow();
rs.beforeFirst();
this.rs=rs;
}
//返回当前页号
public int getCurrentPageNo() {
return currentPageNo;
}
//返回总页数
public int getPageCount() {
// TODO Auto-generated method stub
if(rowsCount == 0) return 0;
if(pageSize == 0) return 1;
double tmpD = (double)rowsCount/pageSize;
int tmpI = (int)tmpD;
if(tmpD > tmpI) tmpI++;
return tmpI;
}
//返回当前页的记录条数
public int getPageRowsCount() {
if(pageSize == 0) return rowsCount;
if(getRowsCount() == 0) return 0;
if(currentPageNo != getPageCount()) return pageSize;
return rowsCount-(getPageCount()-1)*pageSize;
}
//返回分页大小
public int getPageSize() {
return pageSize;
}
//返回每页行数
public int getRowsCount() {
return rowsCount;
}
//跳转到第几页
public void gotoPage(int page) {
if(rs == null) return;
if(page < 1) page = 1;
if(page > getPageCount()) page = getPageCount();
int row = (page - 1) * pageSize + 1;
try {
rs.absolute(row);
currentPageNo = page;
} catch (SQLException e) {
e.printStackTrace();
}
}
//跳转到首页
public void pageFirst() throws SQLException {
int row=(currentPageNo - 1) * pageSize + 1;
rs.absolute(row);
}
//跳转到最后一页
public void pageLast() throws SQLException {
int row=(currentPageNo - 1) * pageSize + getPageRowsCount();
rs.absolute(row);
}
//设置分页大小
public void setPageSize(int pageSize) {
if(pageSize >= 0){
this.pageSize = pageSize;
currentPageNo = 1;
}
}
}
三、JSP页面中分页操作：
<table width="100%" border="0" cellpadding=0 cellspacing=0 align<