spring mvc 分页

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:

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;}@Overridepublic 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

<?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：

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@Overridepublic 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

<%@ 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:

@RequestMapping(value="/list")public ModelAndView listStudent(@ModelAttribute ResultFilter<Student> rf){studentService.listStudent(rf);return new ModelAndView("list", "rf", rf);}

service中的方法:

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。