想学好 java 必须敲坏几个键盘：利用java实现分页

想学好 java必须敲坏几个键盘：利用java实现分页

用到的技术：java源代码。

操作步骤：

1. 创建一个Page类；包括属性有：总页数、每页显示的条数、记录总数、当前页码、一个接受数据的集合。具体见代码

public class Page {

protected int totalPageCount=1;//总页数

protected int pageSize=4; //每页显示页数

protected int totalCount=0;//记录总数

protected int currPageNo=1;//当前页码

List<News> news;

public int getTotalPageCount() {

return totalPageCount;

}

public void setTotalPageCount(int totalPageCount) {

this.totalPageCount =totalPageCount;

}

public int getPageSize() {

return pageSize;

}

public void setPageSize(int pageSize) {

if(this.pageSize>0)

this.pageSize = pageSize;

}

public int getTotalCount() {

return totalCount;

}

public void setTotalCount(int totalCount) {

if(totalCount>0)

this.totalCount = totalCount;

totalPageCount=this.totalCount%pageSize==0?(this.totalCount/pageSize):this.totalCount/pageSize+1;

}

public int getCurrPageNo() {

if(totalPageCount==0)

return 0;

return currPageNo;

}

public void setCurrPageNo(int currPageNo) {

if(this.currPageNo>0)

this.currPageNo = currPageNo;

}

public List<News> getNews() {

return news;

}

public void setNews(List<News> news) {

this.news = news;

}

1. 页面的内容体现出分页：

<c:choose>

<c:whentest=”${page.totalPageCount==1&&page.currPageNo==1}”></c:when>

<c:whentest=”${page.currPageNo==1&& page.totalPageCount>1}”>

<table>

<tr>

< td >

<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.currPageNo+1}”>下一页</a>

&nbsp;&nbsp;<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.totalPageCount}”>末页</a>

</td>

</tr>

</c:when>

<c:whentest=”${page.currPageNo < page.totalPageCount &&page.currPageNo>1}”>

<tr>

<td>

<ahref=”GetNewsServlet?show=shownews&currPageNo=1″>首页</a>

&nbsp;&nbsp;<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.currPageNo-1}”>上一页</a>

</td>

<td>

&nbsp;&nbsp;<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.currPageNo+1}”>下一页</a>

&nbsp;&nbsp;<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.totalPageCount}”>末页</a>

</td>

</tr>

</c:when>

<c:whentest=”${page.currPageNo==page.totalPageCount&&page.totalPageCount>1}”>

<tr>

<td>

<ahref=”GetNewsServlet?show=shownews&currPageNo=1″>首页</a>

&nbsp;&nbsp;<ahref=”GetNewsServlet?show=shownews&currPageNo=${page.currPageNo-1}”>上一页</a>

</td></tr>

</table>

</c:when>

</c:choose>

1. 通过selvert处理实现分页；

Stringshow= request .getParameter(“show”);

System.out.println(show);

Page page=null;

int currPageNo=0;

if(show.equals(“shownews”)){

page=new Page();

NewsDao newsdao=newNewsDaoimpl();

Stringcurr=request.getParameter(“currPageNo”);

if(curr==null||curr.equals(“”)){

curr=”1″;

}

currPageNo=Integer.parseInt(curr);

List<News>newslist= newsdao.getPageNews(currPageNo,page.getPageSize());

page.setNews(newslist);

page.setTotalCount(newsdao.getAllnews().size());

page.setCurrPageNo(currPageNo);

request.setAttribute(“page”,page);

request.setAttribute(“newslist”,newslist);

request.getRequestDispatcher(“admin jsp /manageNews.jsp”).

forward (request, response);

return;

}

1. 分页 sql语句 实现（mysql）：

public List<News> getPageNews(intcurrPageNo, int pageSize) {

Connectionconn=super.getConnection();

PreparedStatementps=null;

List<News>listnews=new ArrayList<News>();

Stringsql=”SELECT * FROM tbl_news ORDER BY newsid DESC ” +

“LIMIT”+((currPageNo-1)*pageSize)+”,”+pageSize;

try{

ps=conn.prepareStatement(sql);

rs =ps.executeQuery();

while(rs.next()){

Newsnews=new News();

news.setNid(rs.getString(“newsid”));

news.setTitle(rs.getString(“title”));

news.setContent(rs.getString(“content”));

news.setWriterDate(rs.getString(“writerdate”));

listnews.add(news);

}

}catch(SQLExceptione){

e.printStackTrace();

}finally{

super.closeAll(conn,ps, rs);

}

returnlistnews;

}

以上是整个分页的源码实现；从页面到处理层到DAO层以及封装的类都有源码，想进一步了解的学生可以留言或私信，这里是石家庄康诺科技java培训班。

康诺科技

2017/6/30