spring mvc 分页
springmvcstringhibernatesessionlist
分页主要需要两个参数：
1、当前页是第几页
2、每页展示多少条数据
先写一个类来封装处理这两个参数:
[java] view plaincopy
package com.smvc.annonation.utils;
import java.io.Serializable;
import java.util.List;
import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;
public class ResultFilter<T> implements Serializable{
private static final long serialVersionUID = 5472321653620726832L;
private final static int DEFAULT_NAVIGATOR_SIZE = 5;
//当前页
private int currentPage = 1;
//每页显示数量
private int pageSize = 5;
//总条数
private int totalCount;
private boolean havaNextPage;
private boolean havePrePage;
private int navigatorSize;
//存放查询结果用的list
private List<T> items;
public ResultFilter(){
}
public ResultFilter(int totalCount, int pageSize, int currentPage) {
this(totalCount, pageSize, currentPage, DEFAULT_NAVIGATOR_SIZE);
}
public ResultFilter(int totalCount, int pageSize, int currentPage,
int navigatorSize) {
this.totalCount = totalCount;
this.pageSize = pageSize;
this.currentPage = currentPage;
this.navigatorSize = navigatorSize;
}
public int getPageCount() {
int pageCount = 0;
if (pageSize != 0) {
pageCount = totalCount / pageSize;
if (totalCount % pageSize != 0)
pageCount++;
}
return pageCount;
}
public int getCurrentPage() {
currentPage = currentPage < getPageCount() ? currentPage :
getPageCount();
currentPage = currentPage < 1 ? 1 : currentPage;
return currentPage;
}
public int getPageSize() {
return pageSize;
}
public int getTotalCount() {
return totalCount;
}
public boolean isHaveNextPage() {
havaNextPage = false;
if ((getPageCount() > 1) && (getPageCount() > getCurrentPage()))
havaNextPage = true;
return havaNextPage;
}
public boolean isHavePrePage() {
havePrePage = false;
if ((getPageCount() > 1) && (currentPage > 1))
havePrePage = true;
return havePrePage;
}
private int getNavigatorIndex(boolean isBegin) {
int beginNavigatorIndex = getCurrentPage() - navigatorSize / 2;
int endNavigatorIndex = getCurrentPage() + navigatorSize / 2;
beginNavigatorIndex = beginNavigatorIndex < 1 ? 1 : beginNavigatorIndex;
endNavigatorIndex = endNavigatorIndex < getPageCount() ?
endNavigatorIndex :
getPageCount();
while ((endNavigatorIndex - beginNavigatorIndex) < navigatorSize &&
(beginNavigatorIndex != 1 || endNavigatorIndex != getPageCount())) {
if (beginNavigatorIndex > 1)
beginNavigatorIndex--;
else if (endNavigatorIndex < getPageCount())
endNavigatorIndex++;
}
if(isBegin)
return beginNavigatorIndex;
else
return endNavigatorIndex;
}
public int getBeginNavigatorIndex() {
return getNavigatorIndex(true);
}
public int getEndNavigatorIndex() {
return getNavigatorIndex(false);
}
public List<T> getItems() {
return items;
}
public void setItems(List<T> items) {
this.items = items;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this, ToStringStyle.MULTI_LINE_STYLE);
}
}
接着，就要处理如何翻页的问题。解决方法就是在页面间传递参数，传递当前是第几页。
使用自己定义标签实现比较简便（由于现在只做了一个页面，并不能保证翻页功能的通用性，以后会慢慢完善）
自定义标签的配置:
my.tld
[html] view plaincopy
<?xml version="1.0" encoding="UTF-8"?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<description>My Tag Library</description>
<tlib-version>1.0</tlib-version>
<short-name>my</short-name>
<uri>my-taglib</uri>
<tag>
<description>split page</description>
<name>paging</name>
<tag-class>com.smvc.annonation.tag.PagingTag</tag-class>
<body-content>empty</body-content>
<attribute>
<description>base href</description>
<name>href</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description>curr page</description>
<name>curr</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description>page size</description>
<name>size</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description>total page</description>
<name>total</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description>curr parameter name</description>
<name>cparam</name>
<required>false</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
<attribute>
<description>page size parameter name</description>
<name>sparam</name>
<required>false</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
<dynamic-attributes>false</dynamic-attributes>
</tag>
<tag>
<description>front split page</description>
<name>frontPaging</name>
<tag-class>com.aspire.cms.demo.framework.tag.FrontPagingTag</tag-class>
<body-content>empty</body-content>
<attribute>
<description>base href</description>
<name>href</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<description>result filter</description>
<name>rf</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<dynamic-attributes>false</dynamic-attributes>
</tag>
</taglib>
对应的java类：
[java] view plaincopy
package com.smvc.annonation.tag;
import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import org.apache.commons.lang.StringUtils;
public class PagingTag extends SimpleTagSupport {
private String href;
//当前页
private String cparam;
//每页条数
private String sparam;
private int curr;//当前页
private int size;//每页条数
private int total;//总页数
@Override
public void doTag() throws JspException, IOException {
JspWriter out = getJspContext().getOut();
if(StringUtils.isEmpty(cparam)) {
cparam = "currentPage";
}
if(StringUtils.isEmpty(sparam)) {
sparam = "pageSize";
}
if(!href.endsWith("?") && !href.endsWith("&")) {
if(href.indexOf("?") == -1) {
href = href + "?";
} else {
href = href + "&";
}
}
if (curr <= 0) {
curr = 1;
} else if (curr > total) {
curr = total;
}
out.append("<span>");
// 首页
if (curr == 1) {
out.append("首页");
} else {
href(out, href, 1, "首页");
}
out.append(" | ");
// 上一页
if (curr == 1) {
out.append("上一页");
} else {
href(out, href, curr - 1, "上一页");
}
out.append(" | ");
// 下一页
if (curr == total) {
out.append("下一页");
} else {
href(out, href, curr + 1, "下一页");
}
out.append(" | ");
// 末页
if (curr == total) {
out.append("末页");
} else {
href(out, href, total, "末页");
}
out.append("</span>");
out.append("<span>第");
out.append(curr + "/" + total);
out.append("页</span>");
super.doTag();
}
private void href(JspWriter out, String href, int curr, String title) throws IOException {
out.append("<a href=\"").append(href).append(cparam).append("=").append("" + curr).append("&").append(sparam).append("=").append("" + size).append("\">").append(title).append("</a>");
}
public int getCurr() {
return curr;
}
public void setCurr(int curr) {
this.curr = curr;
}
public int getTotal() {
return total;
}
public void setTotal(int total) {
this.total = total;
}
public String getHref() {
return href;
}
public void setHref(String href) {
this.href = href;
}
public String getCparam() {
return cparam;
}
public void setCparam(String cparam) {
this.cparam = cparam;
}
public String getSparam() {
return sparam;
}
public void setSparam(String sparam) {
this.sparam = sparam;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
}
在jsp中使用自定义的标签库来实现翻页功能：
list.jsp
[javascript] view plaincopy
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" %>
<%@ page session="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib uri="my-taglib" prefix="my"%>
<title>学生列表</title>
<form action="list" method="post">
<table>
<tr>
<td width="160">id</td>
<td width="160">姓名</td>
<td width="160">性别</td>
<td width="160">年龄</td>
<td width="160">生日</td>
</tr>
<c:forEach items="${rf.items}" var="student">
<tr>
<td><c:out value="${student.id}"/></td>
<td><c:out value="${student.name}"/></td>
<td><c:out value="${student.gender}"/></td>
<td><c:out value="${student.age}"/></td>
<td><fmt:formatDate value="${student.birthday}" type="both" pattern="yyyy-MM-dd"/></td>
</tr>
</c:forEach>
</table>
<my:paging curr="${rf.currentPage}" total="${rf.pageCount}" size="${rf.pageSize}" href="list"/>
</form>
controller中根据参数对ResultFilter进行设置:
[java] view plaincopy
@RequestMapping(value="/list")
public ModelAndView listStudent(@ModelAttribute ResultFilter<Student> rf){
studentService.listStudent(rf);
return new ModelAndView("list", "rf", rf);
}
service中的方法:
[java] view plaincopy
public void listStudent(ResultFilter<Student> rf){
rf.setTotalCount(getStudentCount());
rf.setItems(studentDao.getListForPage("from Student", (rf.getCurrentPage() - 1 )* rf.getPageSize(), rf.getPageSize()));
}
这个方法没有使用session,能支持多台服务器共同提供服务的情况。但是这个方法的效率可能有点低，因为每次翻页的时候都会重新创建一个ResultFilter，使用hibernate的缓存应该会使性能有所提高。
