java面试分页代码 javaee分页功能的实现和原理

java面试的时候问到如何实现分页?

分页的实现可分为两大类相信你也懂得这个，一、数据在Java代码中进行分页，然后取得当前页数据；二、在数据库中直接取得当前页数据。

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通常面试官都希望听到后者，因为那才是高效的方法。你如果想让面试官觉得你的能力高的话你就先否定他的问题，你可以回答说：“Java中根本不需要做分页的实现代码只管拿数据库中的当前页数据即可，数据分页功能应该交由SQL处理，在分页实现中Java最多只实现总页数的计算，除此以外几乎不用管。”如果你这么答的话面试官通常会问你总页数的算法，至于这个你可以网上找个高效点的方法，我现在知道最高效的就是：(数据总行数+每页数据行数-1)/每页数据行数。

算法可能有更高效的，你可以到网上找找。记住只在面试中才能这么答，笔试的话老老实实写出实现方法。否定面试官的问题会让他觉得你更professional，但不要太嚣张不然适得其反的。

通常面试如果他狂问我代码实现的话我都会要回简历走人，因为他们需要的只是一个Coder。

谁能给我个完整的java 分页代码 谢谢了

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;

import com.lqh.dao.db.DBCon;

public class PageDAO {

public static final String Text = "text";

public static final String Image = "image";

public static final String BbsText = "bbstext";

public static final String BbsImage = "bbsimage";

private HttpServletRequest request;

private int currentpage = 1; // 当前是第几页

private int pagecount = 0; // 一共有多少页

private int rscount = 0; // 一共有多少行

private int pagesize = 10; // 每页有多少行[默认为20行]

public PageDAO(HttpServletRequest request) {

this.request = request;

}

public int getCurrentpage() {

return currentpage;

}

public void setCurrentpage(int currentpage) {

this.currentpage = currentpage;

}

public int getPagecount() {

return pagecount;

}

public void setPagecount(int pagecount) {

this.pagecount = pagecount;

}

public int getPagesize() {

return pagesize;

}

public void setPagesize(int pagesize) {

this.pagesize = pagesize;

}

public int getRscount() {

return rscount;

}

public void setRscount(int rscount) {

this.rscount = rscount;

}

/**

* 传入SQL语句获取总记录数

*/

public int getRsCountForRs(String sql) {

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

DBCon dbcon=new DBCon();

try {

conn = dbcon.getConn();

ps = conn.prepareStatement(sql);

rs = ps.executeQuery();

if (rs.next()) {

rs.last();

this.rscount = rs.getRow();

} else {

this.rscount = 0;

}

} catch (Exception ex) {

ex.printStackTrace();

this.rscount = 0;

} finally {

dbcon.tryClose(rs, ps, conn);

}

return this.rscount;

}

public int getRsCountForSQL(String sql) {

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

DBCon dbcon=new DBCon();

try {

conn = dbcon.getConn();

ps = conn.prepareStatement(sql);

rs = ps.executeQuery();

if (rs.next()) {

this.rscount = rs.getInt("rscount");

} else {

this.rscount = 0;

}

} catch (Exception ex) {

ex.printStackTrace();

this.rscount = 0;

} finally {

dbcon.tryClose(rs, ps, conn);

}

return this.rscount;

}

/**

* 获取总页数

*

* @return int

*/

public int getPageCount() {

try {

this.pagecount = ((this.rscount - 1) / this.pagesize) + 1;

} catch (Exception ex) {

this.pagecount = 0;

}

return this.pagecount;

}

/**

* 获取当前页码的设置

*

* @return int

*/

public int getCurrentPage() {

try {

if (this.request.getParameter("currentpage") != null

Integer.parseInt(this.request

.getParameter("currentpage")) 1) {

this.currentpage = Integer.parseInt(this.request

.getParameter("currentpage"));

} else {

this.currentpage = 1;

}

} catch (Exception ex) {

this.currentpage = 1;

}

return this.currentpage;

}

/**

* 分页工具条

*

* @param fileName

* String

* @return String

*/

public String pagetool(String flag) {

StringBuffer str = new StringBuffer();

String url = this.getParamUrl();

int ProPage = this.currentpage - 1;

int Nextpage = this.currentpage + 1;

// 文字的分页

if (flag.equals(PageDAO.Text)) {

str.append("form method='post' name='pageform' action=''");

str

.append("table style='color: windowframe' width='100%' border='0' cellspacing='0' cellpadding='0'");

str.append("tr");

str.append("td width='20%'/td");

str.append("td height='26'");

str.append("共有记录" + this.rscount + "条 ");

str.append("共" + this.pagecount + "页 ");

str.append("每页" + this.pagesize + "记录 ");

str.append("现在" + this.currentpage + "/" + this.pagecount + "页");

str.append("/tdtd");

if (this.currentpage 1) {

str.append("a href='" + url + "currentpage=1'首页/a");

str.append(" ");

str.append("a href='" + url + "currentpage=" + ProPage

+ "'上一页/a");

str.append(" ");

} else {

str.append("首页");

str.append(" ");

str.append("上一页");

str.append(" ");

}

if (this.currentpage this.pagecount) {

str.append("a href='" + url + "currentpage=" + Nextpage

+ "'下一页/a");

str.append(" ");

} else {

str.append("下一页");

str.append(" ");

}

if (this.pagecount 1 this.currentpage != this.pagecount) {

str.append("a href='" + url + "currentpage=" + pagecount

+ "'尾页/a");

str.append(" ");

} else {

str.append("尾页");

str.append(" ");

}

str.append("转到");

str

.append("select name='currentpage' onchange='javascript:ChangePage(this.value);'");

for (int j = 1; j = pagecount; j++) {

str.append("option value='" + j + "'");

if (currentpage == j) {

str.append("selected");

}

str.append("");

str.append("" + j + "");

str.append("/option");

}

str.append("/select页");

str.append("/tdtd width='3%' /td/tr/table");

str.append("script language='javascript'");

str.append("function ChangePage(testpage){");

str.append("document.pageform.action='" + url

+ "currentpage='+testpage+'';");

str.append("document.pageform.submit();");

str.append("}");

str.append("/script");

str.append("/form");

} else if (flag.equals(PageDAO.Image)) {

/**

* 图片的分页

*/

} else if (flag.equals(PageDAO.BbsText)) {

/**

* 论坛形式的分页[直接以数字方式体现]

*/

str

.append("table width='100%' border='0' cellspacing='0' cellpadding='0'");

str.append("tr");

str.append("td width='3%' /td");

str.append("td height='26'");

str.append("记录" + this.rscount + "条  ");

str.append("共" + this.pagecount + "页  ");

str.append("每页" + this.pagesize + "记录  ");

str.append("现在" + this.currentpage + "/" + this.pagecount + "页");

str.append("/tdtd");

// 设定是否有首页的链接

if (this.currentpage 1) {

str.append("a href='" + url + "currentpage=1'首页/a");

str.append("  ");

}

// 设定是否有上一页的链接

if (this.currentpage 1) {

str.append("a href='" + url + "currentpage=" + ProPage

+ "'上一页/a");

str.append("   ");

}

// 如果总页数只有10的话

if (this.pagecount = 10) {

for (int i = 1; i = this.pagecount; i++) {

if (this.currentpage == i) {

str.append("font color=red[" + i

+ "]/font  ");

} else {

str.append("a href='" + url + "currentpage=" + i

+ "'" + i + "/a  ");

}

}

} else {

// 说明总数有超过10页

// 制定特环的开始页和结束页

int endPage = this.currentpage + 4;

if (endPage this.pagecount) {

endPage = this.pagecount;

}

int startPage = 0;

if (this.pagecount = 8 this.currentpage = 8) {

startPage = this.currentpage - 5;

} else {

// 表示从第一页开始算

startPage = 1;

}

System.out.println(startPage);

System.out.println(endPage);

for (int i = startPage; i = endPage; i++) {

if (this.currentpage == i) {

str.append("font color=red[" + i

+ "]/font  ");

} else {

str.append("a href='" + url + "currentpage=" + i

+ "'" + i + "/a  ");

}

}

}

// 设定是否有下一页的链接

if (this.currentpage this.pagecount) {

str.append("a href='" + url + "currentpage=" + Nextpage

+ "'下一页/a");

str.append("  ");

}

// 设定是否有尾页的链接

if (this.pagecount 1 this.currentpage != this.pagecount) {

str.append("a href='" + url + "currentpage=" + pagecount

+ "'尾页/a");

str.append("  ");

}

str.append("/tdtd width='3%' /td/tr/table");

} else if (flag.equals(PageDAO.BbsImage)) {

/**

* 论坛形式的分页[以图片的方式体现]

*/

// 设定分页显示的CSS

str.append("style");

str

.append("BODY {FONT-SIZE: 12px;FONT-FAMILY:宋体;WIDTH: 60%; PADDING-LEFT: 25px;}");

str

.append("DIV.meneame {PADDING-RIGHT: 3px; PADDING-LEFT: 3px; FONT-SIZE: 80%; PADDING-BOTTOM: 3px; MARGIN: 3px; COLOR: #ff6500; PADDING-TOP: 3px; TEXT-ALIGN: center}");

str

.append("DIV.meneame A {BORDER-RIGHT: #ff9600 1px solid; PADDING-RIGHT: 7px; BACKGROUND-POSITION: 50% bottom; BORDER-TOP: #ff9600 1px solid; PADDING-LEFT: 7px; BACKGROUND-IMAGE: url('"

+ this.request.getContextPath()

+ "/meneame.jpg'); PADDING-BOTTOM: 5px; BORDER-LEFT: #ff9600 1px solid; COLOR: #ff6500; MARGIN-RIGHT: 3px; PADDING-TOP: 5px; BORDER-BOTTOM: #ff9600 1px solid; TEXT-DECORATION: none}");

str

.append("DIV.meneame A:hover {BORDER-RIGHT: #ff9600 1px solid; BORDER-TOP: #ff9600 1px solid; BACKGROUND-IMAGE: none; BORDER-LEFT: #ff9600 1px solid; COLOR: #ff6500; BORDER-BOTTOM: #ff9600 1px solid; BACKGROUND-COLOR: #ffc794}");

str

.append("DIV.meneame SPAN.current {BORDER-RIGHT: #ff6500 1px solid; PADDING-RIGHT: 7px; BORDER-TOP: #ff6500 1px solid; PADDING-LEFT: 7px; FONT-WEIGHT: bold; PADDING-BOTTOM: 5px; BORDER-LEFT: #ff6500 1px solid; COLOR: #ff6500; MARGIN-RIGHT: 3px; PADDING-TOP: 5px; BORDER-BOTTOM: #ff6500 1px solid; BACKGROUND-COLOR: #ffbe94}");

str

.append("DIV.meneame SPAN.disabled {BORDER-RIGHT: #ffe3c6 1px solid; PADDING-RIGHT: 7px; BORDER-TOP: #ffe3c6 1px solid; PADDING-LEFT: 7px; PADDING-BOTTOM: 5px; BORDER-LEFT: #ffe3c6 1px solid; COLOR: #ffe3c6; MARGIN-RIGHT: 3px; PADDING-TOP: 5px; BORDER-BOTTOM: #ffe3c6 1px solid}");

str.append("/style");

str.append("div class=\"meneame\"");

// 判定是否有上一页

if (this.currentpage 1) {

str.append("a href='" + url

+ "currentpage=1' hidefocus=\"true\"首页/a");

str.append("   ");

str.append("a href='" + url + "currentpage=" + ProPage

+ "' hidefocus=\"true\"上一页/a");

str.append("   ");

} else {

str.append("span class=\"disabled\"首页/span");

str.append("  ");

str.append("span class=\"disabled\"上一页/span");

str.append("  ");

}

// 显示中间的图片

if (this.pagecount = 10) {

for (int i = 1; i = this.pagecount; i++) {

if (this.currentpage == i) {

str.append("span class=\"current\"" + i + "/span");

} else {

str.append("a href='" + url + "currentpage=" + i

+ "' hidefocus=\"true\"" + i

+ "/a  ");

}

}

} else {

// 说明总数有超过10页

// 制定特环的开始页和结束页

int endPage = this.currentpage + 4;

if (endPage this.pagecount) {

endPage = this.pagecount;

}

int startPage = 0;

if (this.pagecount = 8 this.currentpage = 8) {

startPage = this.currentpage - 5;

} else {

// 表示从第一页开始算

startPage = 1;

}

System.out.println(startPage);

System.out.println(endPage);

for (int i = startPage; i = endPage; i++) {

if (this.currentpage == i) {

str.append("span class=\"current\"" + i + "/span");

} else {

str.append("a href='" + url + "currentpage=" + i

+ "' hidefocus=\"true\"" + i

+ "/a  ");

}

}

}

// 判断下一页和尾页

if (this.currentpage this.pagecount) {

if (this.currentpage this.pagecount - 10) {

str.append("...");

str.append("a href='" + url + "currentpage="

+ (this.pagecount - 1) + "' hidefocus=\"true\""

+ (this.pagecount - 1) + "/a  ");

str.append("a href='" + url + "currentpage="

+ this.pagecount + "' hidefocus=\"true\""

+ this.pagecount + "/a  ");

}

str.append("a href='" + url + "currentpage=" + Nextpage

+ "' hidefocus=\"true\"下一页/a");

str.append("  ");

} else {

str.append("span class=\"disabled\"下一页/span");

str.append("  ");

}

if (this.pagecount 1 this.currentpage != this.pagecount) {

str.append("a href='" + url + "currentpage=" + pagecount

+ "' hidefocus=\"true\"尾页/a");

str.append("  ");

} else {

str.append("span class=\"disabled\"尾页/span");

str.append("  ");

}

str.append("/div");

}

return str.toString();

}

public String getParamUrl() {

String url = "";

url = this.request.getRequestURI().toString();

if (url.indexOf("?") == -1) {

url = url + "?";

}

String totalParams = "";

Enumeration params = this.request.getParameterNames();// 得到所有参数名

while (params.hasMoreElements()) {

String tempName = params.nextElement().toString();

String tempValue = this.request.getParameter(tempName);

if (tempValue != null !tempValue.equals("")

!tempName.equals("currentpage")) {

if (totalParams.equals("")) {

totalParams = totalParams + tempName + "=" + tempValue;

} else {

totalParams = totalParams + "" + tempName + "="

+ tempValue;

}

}

}

String totalUrl = url + totalParams;

return totalUrl;

}

}

java分页怎么实现

body

%! int pageSize=3; //每页显示的记录数

int pageCount=0; //分页后的总页数

%

FORM action="bookfind1.jsp" method=get

输入页码数Input Type="text" name="showPage" size="4"

Input Type="submit" value="提交"

/FORM

%

Connection con;

Statement sql;

try{

Class.forName("com.mysql.jdbc.Driver");

}

catch(ClassNotFoundException e){}

con=DriverManager.getConnection("jdbc:mysql://localhost:3306/tybook","root","123");

sql=con.createStatement();

Statement sql1 = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);

//返回可滚动的结果集：

ResultSet rs=sql1.executeQuery("SELECT * FROM books");

rs.last(); //将游标移动到最后一行

int lastRow=rs.getRow(); //获取最后一行的行号

//计算分页后的总页数

pageCount=(lastRow%pageSize==0)?(lastRow/pageSize):(lastRow/pageSize+1);

int showPage=1; //当前显示的初始页数

%

P 共有%=pageCount%页

每页显示%=pageSize%条记录.

%

String integer=request.getParameter("showPage");//获取客户输入页数

System.out.print(integer);

if(integer==null){

integer="1";

}

try {

showPage=Integer.parseInt(integer);

}

catch(NumberFormatException e){

showPage=1;

}

if(showPage=1){

showPage=1;

}

if(showPage=pageCount){

showPage=pageCount;

}

%

BR目前显示第%=showPage%页

%

//如果要显示第showPage页，那么计算游标应移到位置posion

int posion=(showPage-1)*pageSize+1;

rs.absolute(posion); // 设置游标的位置

out.print("Table Border bgcolor='74bbc0'");

out.print("TR");

out.print("TH width=100"+"学号");

out.print("TH width=100"+"姓名");

out.print("TH width=50"+"学分");

out.print("/TR");

for (int i=1;i=pageSize;i++){

out.print("TR");

out.print("TD "+rs.getString(1)+"/TD");

out.print("TD "+rs.getString(2)+"/TD");

out.print("TD "+rs.getString(3)+"/TD");

out.print("/TR") ;

rs.next();

}

out.print("/Table");

con.close(); //关闭连接

%

/body

求java分页代码，急用！

package common.util;

import java.util.*;

public class PageController implements IPageModel {

private Collection model;

//数据总行数

private int totalRowCount = 0; //

//总页数

private int pageCount = 0;

//每页应显示的行数

private int maxPageRowCount = 0;

//当前页行数

private int currPageRowCount = 0;

//当前页号

private int currPageNum;

//默认构造

public PageController() {

super();

}

//传入模型

public PageController(Collection model) {

setPageController(model);

}

//设一个分页模型

public void setPageController(Collection model) {

this.model = model;

this.totalRowCount = model.size();

}

/**

* 总页数

* @return int

*/

public int getPageCount() {

return this.pageCount;

}

/**

* getPageContents

*

* @param intPageNum int

* @return Object

*/

public Object getPageContents(int intPageNum) {

//非法数据

if(intPageNum1){

intPageNum=1;

}

if(intPageNumpageCount){

intPageNum=pageCount;

}

//指定当前页

this.currPageNum=intPageNum;

int i = 0;

ArrayList arr = new ArrayList();

//如果是合法的范围

if (intPageNum 0 intPageNum = pageCount) {

//计算该页的开始号和结束号

int lfromrow = (intPageNum - 1) * maxPageRowCount;

arr = (ArrayList) getElementsAt(model, lfromrow, lfromrow + maxPageRowCount-1);

}

currPageNum=intPageNum;

return arr;

}

public Object getLastPage() {

return this.getPageContents(pageCount);

}

public Object getFirstPage() {

return this.getPageContents(0);

}

/**

* getCurrentPageRowsCount

*

* @return int

*/

public int getCurrentPageRowsCount() {

if(currPageNumpageCount){

return maxPageRowCount;

}

else{//最后一页

return totalRowCount-(pageCount-1)*maxPageRowCount;

}

}

public int getCurrentPageNum(){

return currPageNum;

}

/**

* setMaxPageRows

*

* @return int

*/

public void setMaxPageRows(int rowCount) {

maxPageRowCount = rowCount;

//计算总页数

if (totalRowCount % maxPageRowCount 0) { //有余数

pageCount = totalRowCount / maxPageRowCount + 1;

}

else {

pageCount = totalRowCount / maxPageRowCount;

}

}

/**

* getMaxPageRows

*/

public int getMaxPageRows() {

return maxPageRowCount;

}

//私有方法，返回集合中指定范围的数据

private Object getElementsAt(Collection model, int fromIndex, int toIndex) {

Iterator iter = model.iterator();

ArrayList arr = new ArrayList();

if (iter != null) {

int i = 0;

while (iter.hasNext()) {

Object obj=iter.next();

if (i = fromIndex i = toIndex) {

arr.add(obj);

}

if (i toIndex) {

break;

}

i = i + 1;

}

}

return arr;

}

}