【Java EE】pager-taglib 2.0实现分页--笔记

1、分页显示中必须有两个参数,总记录数、记录列表,封装到PagerModel类中
PagerModel.java
 1package com.oa;
 2
 3import java.util.List;
 4
 5import com.oa.models.Organization;
 6
 7/**
 8 * 
 9 * @author Administrator 分页模型,返回记录总数和相应记录
10 */

11public class PagerModel {
12    private int total;
13    private List<Organization> list;
14
15    public int getTotal() {
16        return total;
17    }

18
19    public void setTotal(int total) {
20        this.total = total;
21    }

22
23    public List<Organization> getList() {
24        return list;
25    }

26
27    public void setList(List<Organization> list) {
28        this.list = list;
29    }

30}
2、显示页showorgs.jsp代码如下:
 1<%@ page language="java" contentType="text/html; charset=GB18030"
 2    pageEncoding="GB18030"
%>
 3<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
 4<%@ taglib prefix="pg" uri="http://jsptags.com/tags/navigation/pager"%>
 5<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 6<html>
 7    <head>
 8        <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
 9        <title>Insert title here</title>
10    </head>
11    <body>
12        <table>
13            <tr>
14                <td>
15                    序号
16                </td>
17                <td>
18                    机构名称
19                </td>
20                <td>
21                    机构编号
22                </td>
23                <td>
24                    父机构名称
25                </td>
26                <td>
27                    相关操作
28                </td>
29            </tr>
30            <c:if test="${!empty pagerModel.list}">
31                <c:forEach items="${pagerModel.list}" var="org">
32                    <tr>
33                        <td>
34                            ${org.orgid }
35                        </td>
36                        <td>
37                            ${org.orgname }
38                        </td>
39                        <td>
40                            ${org.orgsn }
41                        </td>
42                        <td>
43                            ${org.parentorg.orgname }
44                        </td>
45                        <td>
46                            <href="#">删除</a>
47                        </td>
48                    </tr>
49                </c:forEach>
50            </c:if>
51            <c:if test="${empty pagerModel.list}">
52                <tr>
53                    <td colspan="5">
54                        没有找到相应的记录
55                    </td>
56                </tr>
57            </c:if>
58        </table>
59        <pg:pager items="${pagerModel.total}" url="organization.action"
60            export="currentPageNumber=pageNumber" maxIndexPages="5"
61            maxPageItems="8">
62            <pg:param name="parentorgid" />
63            <pg:first>
64                <href="${pageUrl }">首页</a>
65            </pg:first>
66            <pg:prev>
67                <href="${pageUrl }">前一页</a>
68            </pg:prev>
69            <pg:pages>
70                <c:choose>
71                    <c:when test="${currentPageNumber eq pageNumber}">
72                        <font color="red">${pageNumber}</font>
73                    </c:when>
74                    <c:otherwise>
75                        <href="${pageUrl }">${pageNumber }</a>
76                    </c:otherwise>
77                </c:choose>
78            </pg:pages>
79            <pg:next>
80                <href="${pageUrl }">后一页</a>
81            </pg:next>
82            <pg:last>
83                <href="${pageUrl }">尾页</a>
84            </pg:last>
85        </pg:pager>
86    </body>
87</html>
本页代码只对对应的记录做分页显示,并未对数据的操作做处理。

url::分页的链接根地址,pager标签会在这个链接的基础上附加分页参数 
 items:总记录数,pager标签正是根据这个值来计算分页参数的 
maxPageItems:每页显示的行数,默认为10   
maxIndexPages:在循环输出页码的时候,最大输出多少个页码,默认是10   
<pg:param>这个标签很有用,用来设置将要加入到URL的参数。使用Name属性指定即可。
<pg:prev> , <pg:pages>,<pg:next>这些标签都是导航标签顾名思义

3、Action的实现
OrganizationAction.java
 1package com.oa.actions;
 2
 3import org.apache.struts2.ServletActionContext;
 4
 5import com.oa.PagerModel;
 6import com.oa.managers.OrganizationManager;
 7import com.opensymphony.xwork2.ActionSupport;
 8
 9@SuppressWarnings("serial")
10public class OrganizationAction extends ActionSupport {
11
12    private OrganizationManager organizationManager;
13
14    private int parentorgid;
15
16    private PagerModel pagerModel;
17
18    public int getParentorgid() {
19        return parentorgid;
20    }

21
22    public void setParentorgid(int parentorgid) {
23        this.parentorgid = parentorgid;
24    }

25
26    public void setOrganizationManager(OrganizationManager organizationManager) {
27        this.organizationManager = organizationManager;
28    }

29
30    public PagerModel getPagerModel() {
31        return pagerModel;
32    }

33
34    public void setPagerModel(PagerModel pagerModel) {
35        this.pagerModel = pagerModel;
36    }

37
38    @Override
39    public String execute() throws Exception {
40        /*
41         * int offset = 0;
42         * 
43         * try { offset = Integer.parseInt(ServletActionContext.getRequest()
44         * .getParameter("pager.offset")); } catch (RuntimeException e) { //
45         * TODO Auto-generated catch block e.printStackTrace(); } int pagesize =
46         * 8;
47         */

48        System.out.println("parentorgid:"+parentorgid);
49        pagerModel = organizationManager.findOrgs(parentorgid);// ,
50                                                                // offset,pagesize);
51        ServletActionContext.getRequest()
52                .setAttribute("pagerModel", pagerModel);
53        ServletActionContext.getRequest().setAttribute("parentorgid",
54                parentorgid);
55        return SUCCESS;
56    }

57
58}
AbstractorPagerManager.java
 1package com.oa.managers.impl;
 2
 3import java.util.List;
 4
 5import org.hibernate.Query;
 6import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
 7
 8import com.oa.PagerModel;
 9import com.oa.SystemContext;
10import com.oa.models.Organization;
11
12public class AbstractorPagerManager extends HibernateDaoSupport {
13    @SuppressWarnings("unchecked")
14    public PagerModel searchPaginated(String hql) {
15        return this.searchPaginated(hql, null, SystemContext.getOffset(), SystemContext.getPagesize());
16    }

17    public PagerModel searchPaginated(String hql, Object obj) {
18        return this.searchPaginated(hql, new Object[] { obj }, SystemContext.getOffset(), SystemContext.getPagesize());
19    }

20    public PagerModel searchPaginated(String hql, Object[] params) {
21        return this.searchPaginated(hql, params, SystemContext.getOffset(), SystemContext.getPagesize());
22    }

23    public PagerModel searchPaginated(String hql, int offset, int pagesize) {
24        return this.searchPaginated(hql, null, offset, pagesize);
25    }

26
27    public PagerModel searchPaginated(String hql, Object obj, int offset,
28            int pagesize) {
29        return this
30                .searchPaginated(hql, new Object[] { obj }, offset, pagesize);
31    }

32
33    @SuppressWarnings("unchecked")
34    public PagerModel searchPaginated(String hql, Object[] params, int offset,
35            int pagesize) {
36        // 查询总的记录数
37        String countHql = this.getCountHql(hql);
38        Query query = this.getSession().createQuery(countHql);
39        if (query != null && params != null && params.length > 0{
40            for (int i = 0; i < params.length; i++{
41                query.setParameter(i, params[i]);
42            }

43        }

44        int total = ((Long) query.uniqueResult()).intValue();
45
46        // 查询机构列表
47
48        query = this.getSession().createQuery(hql);
49        if (query != null && params != null && params.length > 0{
50            for (int i = 0; i < params.length; i++{
51                query.setParameter(i, params[i]);
52            }

53        }

54        query.setFirstResult(offset);
55        query.setMaxResults(pagesize);
56        List<Organization> list = query.list();
57
58        PagerModel pagerModel = new PagerModel();
59        pagerModel.setTotal(total);
60        pagerModel.setList(list);
61        return pagerModel;
62
63    }

64
65    private String getCountHql(String hql) {
66        int index = hql.indexOf("from");
67        if (index != -1{
68            return "select count(*) " + hql.substring(index);
69        }

70        throw new RuntimeException("不合法的HQL语句!");
71    }

72
73}
OrganizationManagerImpl.java
 1package com.oa.managers.impl;
 2
 3import com.oa.PagerModel;
 4import com.oa.managers.OrganizationManager;
 5import com.oa.models.Organization;
 6
 7public class OrganizationManagerImpl extends AbstractorPagerManager implements
 8        OrganizationManager {
 9
10    public void addOrg(Organization org, int parentorgid) {
11
12        if (parentorgid != 0{
13            org.setParentorg((Organization) this.getHibernateTemplate().load(
14                    Organization.class, parentorgid));
15        }

16
17        this.getHibernateTemplate().save(org);
18
19        // TODO 设置Organization的唯一编号
20        org.setOrgsn(org.getParentorg() == null ? ("" + org.getOrgid()) : (org
21                .getParentorg().getOrgsn()
22                + "_" + org.getOrgid()));
23
24        this.getHibernateTemplate().update(org);
25    }

26
27    public void deleteOrg(int orgid) {
28        this.getHibernateTemplate().delete(
29                this.getHibernateTemplate().load(Organization.class, orgid));
30
31    }

32
33    public Organization findOrg(int orgid) {
34        return (Organization) this.getHibernateTemplate().load(
35                Organization.class, orgid);
36    }

37
38    public void modifyOrg(Organization org, int parentorgid) {
39        if (parentorgid != 0{
40            org.setParentorg((Organization) this.getHibernateTemplate().load(
41                    Organization.class, parentorgid));
42        }

43
44        this.getHibernateTemplate().update(org);
45    }

46
47    @SuppressWarnings("unchecked")
48    public PagerModel findOrgs(int parentorgid) {// , int offset, int
49                                                    // pagesize) {
50        /*
51         * // 查询总的记录数 String selectCountHql = "select count(*) from Organization
52         * org where org.parentorg is null"; if (parentorgid != 0) {
53         * selectCountHql = "select count(*) from Organization org where
54         * org.parentorg.orgid=" + parentorgid; } int total = ((Long)
55         * this.getSession().createQuery(selectCountHql)
56         * .uniqueResult()).intValue(); // 查询机构列表 String selectHql = "from
57         * Organization org where org.parentorg is null"; if (parentorgid != 0) {
58         * selectHql = "from Organization org where org.parentorg.orgid=" +
59         * parentorgid; } List<Organization> list =
60         * this.getSession().createQuery(selectHql)
61         * .setFirstResult(offset).setMaxResults(pagesize).list(); PagerModel
62         * pagerModel = new PagerModel(); pagerModel.setTotal(total);
63         * pagerModel.setList(list); return pagerModel;
64         */

65
66        if (parentorgid == 0{
67            /*
68             * return this.searchPaginated( "from Organization org where
69             * org.parentorg is null", offset, pagesize);
70             */

71            return this
72                    .searchPaginated("from Organization org where org.parentorg is null");
73        }

74        /*
75         * return this.searchPaginated( "from Organization org where
76         * org.parentorg.orgid=?", parentorgid, offset, pagesize);
77         */

78
79        return this.searchPaginated(
80                "from Organization org where org.parentorg.orgid=?",
81                parentorgid);
82    }

83}
SystemContext.java
 1package com.oa;
 2
 3public class SystemContext {
 4    public static ThreadLocal<Integer> offset = new ThreadLocal<Integer>();
 5    public static ThreadLocal<Integer> pagesize = new ThreadLocal<Integer>();
 6
 7    public static void setOffset(int offsetValue) {
 8        offset.set(offsetValue);
 9    }

10
11    public static int getOffset() {
12        Integer os = offset.get();
13        if (os == null{
14            return 0;
15        }

16        return os;
17    }

18    public static void removeOffset(){
19        offset.remove();
20    }

21    
22    public static void setPagesize(int pagesizeValue) {
23        pagesize.set(pagesizeValue);
24    }

25
26    public static int getPagesize() {
27        Integer ps = pagesize.get();
28        if (ps == null{
29            return Integer.MAX_VALUE;
30        }

31        return ps;
32    }

33    public static void removePagesize(){
34        pagesize.remove();
35    }

36}
关于Action的配置比较简单,在此不再作介绍。

4、实现并配置过滤器
PagerFilter.java
 1package com.oa.filters;
 2
 3import java.io.IOException;
 4
 5import javax.servlet.Filter;
 6import javax.servlet.FilterChain;
 7import javax.servlet.FilterConfig;
 8import javax.servlet.ServletException;
 9import javax.servlet.ServletRequest;
10import javax.servlet.ServletResponse;
11import javax.servlet.http.HttpServletRequest;
12
13import com.oa.SystemContext;
14
15public class PagerFilter implements Filter {
16
17    public void destroy() {
18
19    }

20
21    public void doFilter(ServletRequest request, ServletResponse response,
22            FilterChain chain) throws IOException, ServletException {
23
24        HttpServletRequest myrequest = (HttpServletRequest) request;
25        SystemContext.setOffset(this.getOffset(myrequest));
26        SystemContext.setPagesize(this.getPagesize());
27        try {
28            chain.doFilter(request, response);
29        }
 catch (Exception e) {
30
31        }
 finally {
32            SystemContext.removeOffset();
33            SystemContext.removePagesize();
34        }

35    }

36
37    protected int getOffset(HttpServletRequest request) {
38        int offset = 0;
39        try {
40            offset = Integer.parseInt(request.getParameter("pager.offset"));
41        }
 catch (NumberFormatException e) {
42            // TODO Auto-generated catch block
43            System.out.println("--------------------");
44            //e.printStackTrace();
45        }

46        return offset;
47    }

48
49    protected int getPagesize() {
50        return 8;
51    }

52
53    public void init(FilterConfig arg0) throws ServletException {
54
55    }

56
57}
在web.xml中配置过滤器,必须放在struts2之前,否则有可能不起作用
    <filter>
        
<filter-name>pagerFilter</filter-name>
        
<filter-class>com.oa.filters.PagerFilter</filter-class>
    
</filter>
    
<filter-mapping>
        
<filter-name>pagerFilter</filter-name>
        
<url-pattern>/*</url-pattern>
    
</filter-mapping>

posted on 2009-04-15 16:52 intrl 阅读(4930) 评论(4)  编辑 收藏 引用 所属分类: JavaStruts2

评论

# re: 【Java EE】pager-taglib 2.0实现分页--笔记 2009-11-13 09:19 xiaotian

你好,用struts2后分页出现的ognl.OgnlException: target is null for setProperty(null, "offset", [Ljava.lang.String;@c3dfb9)问题您是怎么解决的?


谢谢。  回复  更多评论   

# re: 【Java EE】pager-taglib 2.0实现分页--笔记 2009-11-13 20:34 intrl

http://cmm.javaeye.com/blog/491723 这个网址可能有你要找的答案,但是在我的项目中并没有出现您所说的问题,这应该是一个警告而已吧,不影响程序的运行。 @xiaotian
  回复  更多评论   

# re: 【Java EE】pager-taglib 2.0实现分页--笔记 2010-05-26 15:40 ss

这个是尚学堂的oa,新瓶装旧酒,还是struts1的东西  回复  更多评论   

# re: 【Java EE】pager-taglib 2.0实现分页--笔记 2010-08-11 14:07 爱爱爱

兄弟,为什么要配置那个过滤器呢  回复  更多评论   

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