关于Java的分页算法，急！

使用分页类，直接调用就可以，代码如下：

package com.godwin.news.util

import java.io.UnsupportedEncodingException

import java.net.URLDecoder

import java.util.ArrayList

/**

* 分页类,用于封闭分页显示信息

*

* @author javabs

*

*/

public class Pager {

// 当前页

private int currentPage

// 总页数

private int totalPage

// 总记录数

private int totalRecord

// 每页条数

private int pageSize

// 是否有下一页

private int hasNext

private ArrayList keys

private ArrayList values

// 查询串

private String queryString

// 首页

private String firstLink

// 上一页

private String previousLink

// 下一页

private String nextLink

// 尾页

private String lastLink

// 链接

private String forScriptLink

public Pager(int pageSize, String queryString) {

keys = new ArrayList()

values = new ArrayList()

setQueryString(queryString)

setPageSize(pageSize)

}

public String getForScriptLink() {

if (keys.contains("toPage"))

removeKey("toPage")

String tmp = getQueryString()

if (tmp.length() == 0)

return "?"

else

return "?" + tmp + "&"

}

public int getCurrentPage() {

return currentPage

}

public void setCurrentPage(String toPage) {

int tmpage = 1

try {

tmpage = Integer.parseInt(toPage)

} catch (NumberFormatException e) {

tmpage = 1

}

if (tmpage <1)

tmpage = 1

else if (tmpage >getTotalPage())

tmpage = getTotalPage()

currentPage = tmpage

}

public String getFirstLink() {

return getQueryStr(1)

}

public int getHasNext() {

int i = 1

if (getCurrentPage() >= getTotalPage())

i = 0

return i

}

public String getLastLink() {

return getQueryStr(getTotalPage())

}

public String getNextLink() {

return getQueryStr(currentPage == totalPage ? currentPage : (currentPage + 1))

}

public int getPageSize() {

return pageSize

}

public void setPageSize(int pageSize) {

this.pageSize = pageSize

}

public String getPreviousLink() {

return getQueryStr(currentPage == 1 ? currentPage : currentPage - 1)

}

public void setPreviousLink(String previousLink) {

this.previousLink = previousLink

}

public String getQueryString() {

StringBuffer sb = new StringBuffer()

for (int i = 0i <keys.size()i++) {

String key = (String) keys.get(i)

String value = (String) values.get(i)

sb.append("&")

sb.append(key)

sb.append("=")

sb.append(value)

}

return sb.delete(0, 1).toString()

}

public void setQueryString(String queryString) {

if (queryString != null) {

String s[] = queryString.split("&")

for (int i = 0i <s.lengthi++) {

String s1[] = s[i].split("=")

if (s1.length == 2) {

keys.add(s1[0])

values.add(s1[1])

} else {

keys.add(s1[0])

values.add("")

}

}

}

}

public int getTotalPage() {

return totalPage

}

public void setTotalPage() {

if (totalRecord % pageSize == 0) {

totalPage = totalRecord / pageSize

totalPage = totalPage == 0 ? 1 : totalPage

}

else

totalPage = totalRecord / pageSize + 1

}

public int getTotalRecord() {

return totalRecord

}

public void setTotalRecord(int totalRecord) {

this.totalRecord = totalRecord

setTotalPage()

}

public String[] getQueryParameterValues(String key) {

return getQueryParameterValues(key, "UTF-8")

}

public String[] getQueryParameterValues(String key, String decode) {

ArrayList ret = new ArrayList()

for (int i = 0i <keys.size()i++)

if (((String) keys.get(i)).equals(key))

try {

ret.add(URLDecoder.decode((String) values.get(i), decode))

} catch (UnsupportedEncodingException e) {

ret.add((String) values.get(i))

}

if (ret.size() == 0)

return null

String strArr[] = new String[ret.size()]

for (int i = 0i <ret.size()i++)

strArr[i] = (String) ret.get(i)

return strArr

}

public String getQueryParameter(String key) {

return getQueryParameter(key, "UTF-8")

}

public String getQueryParameter(String key, String decode) {

String value = ""

if (key != "toPage") {

try {

value = URLDecoder.decode(getValue(key), decode)

} catch (UnsupportedEncodingException e) {

value = getValue(key)

}

} else {

int tmpage = 1

try {

value = getValue(key)

tmpage = Integer.parseInt(value)

} catch (NumberFormatException e) {

tmpage = 1

} catch (NullPointerException e1) {

tmpage = 1

}

if (tmpage <1)

tmpage = 1

else if (tmpage >getTotalPage())

tmpage = getTotalPage()

value = (new StringBuffer(String.valueOf(tmpage))).toString()

}

return value

}

public void setQueryParameter(String key, String value) {

if (key.equals("toPage"))

removeKey(key)

keys.add(key)

values.add(value)

}

public String getQueryStr(int toPage) {

setQueryParameter("toPage", (new StringBuffer(String.valueOf(toPage))).toString())

return "?" + getQueryString()

}

private String getValue(String key) {

String ret = ""

for (int i = 0i <keys.size()i++) {

if (!((String) keys.get(i)).equals(key))

continue

ret = (String) values.get(i)

break

}

return ret

}

private void removeKey(String key) {

for (int i = 0i <keys.size()i++) {

if (!((String) keys.get(i)).equals(key))

continue

keys.remove(i)

values.remove(i)

break

}

}

public static void main(String args[]) {

String str = "a=中文aa&b=2&c=3&c=4&c=5"

Pager page = new Pager(2, str)

page.setTotalRecord(10)

page.setCurrentPage("1")

System.out.println(page.getFirstLink())

System.out.println(page.getPreviousLink())

System.out.println(page.getNextLink())

System.out.println(page.getLastLink())

String s = page.getQueryParameter("a")

System.out.println("s: " + s)

}

}

start :就是当前页的起始索引,

pageSize :就是每页的条数

count_data :总数据条数

currentPage :就是当前页

countPage :总页数

当前页 的起始索引公式:

总页数 的公式：

---