Struts 实现自定义分页标签

一、实现方式：

（1）添加 tld 配置文件。

在项目的WEB-INF下添加 mytag.tld 文件，内容如下：

<?xml version="1.0" encoding="UTF-8" ?><taglib xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1"> <description>JSTL 1.2 core library</description> <display-name>JSTL core</display-name> <tlib-version>1.0</tlib-version> <short-name>mt</short-name> <uri>/WEB-INF/mytag</uri> <tag> <name>pages</name> <tag-class>cn.guopeng.oa.tag.PagerTag</tag-class> <body-content>empty</body-content> <attribute> <name>currentPage</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>totalPage</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>path</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>params</name> <required>false</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>hasSelect</name> <required>false</required> <rtexprvalue>false</rtexprvalue> <type>java.lang.Boolean</type> </attribute> <attribute> <name>hasGoText</name> <required>false</required> <rtexprvalue>false</rtexprvalue> <type>java.lang.Boolean</type> </attribute> </tag> </taglib>

 

（2）在cn.guopeng.oa.tag包中添加类：PagerTag 主要用来接收参数并传递给PagerImpl类

package cn.guopeng.oa.tag;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.struts2.components.Component;import org.apache.struts2.views.jsp.ComponentTagSupport;import com.opensymphony.xwork2.util.ValueStack;public class PagerTag extends ComponentTagSupport {private String currentPage; // 当前页private String totalPage; // 总页数private String path; // 请求地址private String params; //其他参数private boolean hasSelect;//是否有下拉列表private boolean hasGoText; //是否有跳转文本框省略get、set方法@Overridepublic Component getBean(ValueStack arg0, HttpServletRequest arg1,HttpServletResponse arg2) {return new PagerImpl(arg0); // 返回Pages Component，分页的逻辑处理都在这个Component中}// 获得参数@Overrideprotected void populateParams() {super.populateParams();PagerImpl pagrImpl = (PagerImpl) component;pagrImpl.setCurrentPage(currentPage);pagrImpl.setTotalPage(totalPage);pagrImpl.setPath(path);pagrImpl.setParams(params);pagrImpl.setHasGoText(hasGoText);pagrImpl.setHasSelect(hasSelect);}}

 

（3）在cn.guopeng.oa.tag包中添加类：PagerImpl。根据传过来的参数到值栈中获得相应值，并输出分页。

 package cn.guopeng.oa.tag;import java.io.IOException;import java.io.Writer;import java.util.Iterator;import java.util.Map;import java.util.Map.Entry;import org.apache.struts2.components.Component;import com.opensymphony.xwork2.util.ValueStack;public class PagerImpl extends Component {//接收参数private String currentPage;private String totalPage;private String path;private String params;private boolean hasSelect;//是否有下拉列表private boolean hasGoText; //是否有跳转文本框private int _currentPage;//当前页面private int _totalPage;//总页数private Map<String, Object> _params;//其他参数 省略get、set方法 @Overridepublic boolean start(Writer writer) {boolean result = super.start(writer);String pageParam = ""; // 保存传递页数的参数字符串try {StringBuilder sb = new StringBuilder();boolean isValid = true;Object temp;// 检查必须的参数if (isValid) {if (path != null) {path = path.trim();} else {isValid = false;}}if (isValid) {if (totalPage != null) {totalPage = totalPage.trim();temp = this.getStack().findValue(totalPage); if(temp != null){ _totalPage = (Integer)temp; }else{ isValid = false; }} else {isValid = false;}}if (isValid) {if (currentPage != null) {currentPage = currentPage.trim();temp = this.getStack().findValue(currentPage);if(temp != null){_currentPage = (Integer)temp;pageParam = currentPage;}} else {isValid = false;}}if (isValid) {if (params != null) {params = params.trim();temp = this.getStack().findValue(params);if(temp != null){_params = (Map<String, Object>)temp;}else{isValid = false;}}}if (isValid) {if (1 >= _currentPage) {sb.append("/n");sb.append("首页");sb.append("&nbsp;&nbsp");sb.append("上一页");sb.append("&nbsp;&nbsp;");} else {sb.append("/n");// 输出带链接首页sb.append("<a href=/"");sb.append(path);insertParams(sb);sb.append(pageParam);sb.append("=");sb.append("1");sb.append("/"");sb.append(">");sb.append("首页");sb.append("</a>");sb.append("&nbsp;&nbsp;");// 输出带链接上一页sb.append("<a href=/"");sb.append(path);insertParams(sb);sb.append(pageParam);sb.append("=");sb.append(_currentPage - 1);sb.append("/"");sb.append(">");sb.append("上一页");sb.append("</a>");sb.append("&nbsp;&nbsp;");}if (_totalPage <= _currentPage) {sb.append("/n"); // 源代码换行sb.append("下一页");sb.append("&nbsp;&nbsp");sb.append("末页");sb.append("&nbsp;&nbsp;");} else {sb.append("/n");// 输出带链接下一页sb.append("<a href=/"");sb.append(path);insertParams(sb);sb.append(pageParam);sb.append("=");sb.append(_currentPage + 1);sb.append("/"");sb.append(">");sb.append("下一页");sb.append("</a>");sb.append("&nbsp;&nbsp;");// 输出带链接末页sb.append("<a href=/"");sb.append(path);insertParams(sb);sb.append(pageParam);sb.append("=");sb.append(_totalPage);sb.append("/"");sb.append(">");sb.append("末页");sb.append("</a>");sb.append("&nbsp;&nbsp;");}if (this.hasSelect) {sb.append("/n");sb.append("<form action=/"");sb.append(path);insertParams(sb);sb.append("/" method=/"post/" style=/"display: inline;/">");sb.append("/n");sb.append("跳转到:");sb.append("<select name=/"");sb.append(pageParam);sb.append("/" onchange=/"javascript:this.parentNode.submit()/">");sb.append("/n");for (int i = 1; i <= _totalPage; i++) {if (i == _currentPage) {sb.append("<option value=/"");sb.append(i);sb.append("/" selected=/"selected/">");sb.append(i);sb.append("</option>");} else {sb.append("<option value=/"");sb.append(i);sb.append("/" >");sb.append(i);sb.append("</option>");}}sb.append("/n");sb.append("</select>");sb.append("/n");sb.append("</form>");}if (hasGoText) {sb.append("/n");sb.append("<form action=/"");sb.append(path);insertParams(sb);sb.append("/" method=/"post/" style=/"display: inline;/">");sb.append("/n");sb.append("跳转到:<input type=/"text/" size=/"3/" name=/"");sb.append(pageParam);sb.append("/"/>");sb.append("/n");sb.append("<input type=/"submit/" value=/"Go/"/>");sb.append("/n");sb.append("</form>");}}writer.write(sb.toString());} catch (IOException ex) {ex.printStackTrace();}return result;}private void insertParams(StringBuilder sb) {sb.append("?");if (_params != null) {Iterator<Entry<String, Object>> it = _params.entrySet().iterator();while (it.hasNext()) {Map.Entry<String, Object> entry = (Map.Entry<String, Object>) it.next();String key = entry.getKey();Object val = entry.getValue();sb.append(key);sb.append("=");sb.append(val);sb.append("&");}}}} 

 

（4）请求的Action类

 

package cn.guopeng.oa.action;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.annotation.Resource;import org.springframework.context.annotation.Scope;import org.springframework.stereotype.Component;import cn.guopeng.oa.model.Orgnization;import cn.guopeng.oa.service.IOrgMgr;import com.opensymphony.xwork2.ActionSupport;@Component("orgAction")@Scope("prototype")public class OrgAction extends ActionSupport {private IOrgMgr orgMgr;private int pid;private int currentPage = 1;private int totalPage;private int totalCount;private Orgnization org;private List<Orgnization> orgs;private Map<String, Object> params;省略部分get、set方法public IOrgMgr getOrgMgr() {return orgMgr;}@Resourcepublic void setOrgMgr(IOrgMgr orgMgr) {this.orgMgr = orgMgr;}//列表public String list(){params = new HashMap<String, Object>();params.put("pid", pid);totalPage = orgMgr.getTotalPage(pid);totalCount = orgMgr.getTotalCount(pid);orgs = orgMgr.loadOrgs(pid, currentPage);return "list";}//添加public String addInput(){return "addInput";}//删除public String delete(){if(orgMgr.delete(org.getId()));return "delete";}}

 

（5）使用分页标签的jsp页面：

<mt:pages totalPage="totalPage" currentPage="currentPage" path="${webroot}/orgAction!list" params="params" hasSelect="true" hasGoText="false"/>

（6）测试请求链接：

<%=webroot %>/orgAction!list?pid=1

没有传递currentPage参数原因是在Action中默认为第一页。

（7）其他说明：

在传递的参数中params对应Action中的一个Map类型，用于传递其他的参数，比如上面链接可以写为<%=webroot %>/orgAction!list?pid=1&currentPage=1其中currentPage就是要请求的页数，pid是父类型的id。就如同只取出某一分类中的记录再分页。

 

 

 

二、Struts 自定义标签的执行原理 时序图（部分）：