JSP頁面分頁標籤的使用
阿新 • • 發佈:2018-12-09
1.組成
1. 兩個utils工具類
2. 一個tld檔案
2.NavigationTag.java
package oranges.util;
import java.io.IOException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;
import org.apache.taglibs.standard.tag.common.core.UrlSupport;
/**
* 顯示格式 上一頁 1 2 3 4 5 下一頁
*/
public class NavigationTag extends TagSupport {
static final long serialVersionUID = 2372405317744358833L;
/**
* request 中用於儲存Page<E> 物件的變數名,預設為“page”
*/
private String bean = "page";
/**
* 分頁跳轉的url地址,此屬性必須
*/
private String url = null;
/**
* 顯示頁碼數量
*/
private int number = 5;
@Override
public int doStartTag() throws JspException {
JspWriter writer = pageContext.getOut();
HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();
Page page = (Page)request.getAttribute(bean);
if (page == null)
return SKIP_BODY;
url = resolveUrl(url, pageContext);
try {
//計算總頁數
int pageCount = page.getTotal() / page.getSize();
if (page.getTotal() % page.getSize() > 0) {
pageCount++;
}
writer.print("<nav><ul class=\"pagination\">");
//顯示“上一頁”按鈕
if (page.getPage() > 1) {
String preUrl = append(url, "page", page.getPage() - 1);
preUrl = append(preUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + preUrl + "\">上一頁</a></li>");
} else {
writer.print("<li class=\"disabled\"><a href=\"#\">上一頁</a></li>");
}
//顯示當前頁碼的前2頁碼和後兩頁碼
//若1 則 1 2 3 4 5, 若2 則 1 2 3 4 5, 若3 則1 2 3 4 5,
//若4 則 2 3 4 5 6 ,若10 則 8 9 10 11 12
int indexPage = (page.getPage() - 2 > 0)? page.getPage() - 2 : 1;
for(int i=1; i <= number && indexPage <= pageCount; indexPage++, i++) {
if(indexPage == page.getPage()) {
writer.print( "<li class=\"active\"><a href=\"#\">"+indexPage+"<span class=\"sr-only\">(current)</span></a></li>");
continue;
}
String pageUrl = append(url, "page", indexPage);
pageUrl = append(pageUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + pageUrl + "\">"+ indexPage +"</a></li>");
}
//顯示“下一頁”按鈕
if (page.getPage() < pageCount) {
String nextUrl = append(url, "page", page.getPage() + 1);
nextUrl = append(nextUrl, "rows", page.getSize());
writer.print("<li><a href=\"" + nextUrl + "\">下一頁</a></li>");
} else {
writer.print("<li class=\"disabled\"><a href=\"#\">下一頁</a></li>");
}
writer.print("</nav>");
} catch (IOException e) {
e.printStackTrace();
}
return SKIP_BODY;
}
private String append(String url, String key, int value) {
return append(url, key, String.valueOf(value));
}
/**
* 為url 參加引數對兒
*
* @param url
* @param key
* @param value
* @return
*/
private String append(String url, String key, String value) {
if (url == null || url.trim().length() == 0) {
return "";
}
if (url.indexOf("?") == -1) {
url = url + "?" + key + "=" + value;
} else {
if(url.endsWith("?")) {
url = url + key + "=" + value;
} else {
url = url + "&" + key + "=" + value;
}
}
return url;
}
/**
* 為url 新增翻頁請求引數
*
* @param url
* @param pageContext
* @return
* @throws JspException
*/
private String resolveUrl(String url, javax.servlet.jsp.PageContext pageContext) throws JspException{
//UrlSupport.resolveUrl(url, context, pageContext)
Map params = pageContext.getRequest().getParameterMap();
for (Object key:params.keySet()) {
if ("page".equals(key) || "rows".equals(key)) continue;
Object value = params.get(key);
if (value == null) continue;
if (value.getClass().isArray()) {
url = append(url, key.toString(), ((String[])value)[0]);
} else if (value instanceof String) {
url = append(url, key.toString(), value.toString());
}
}
return url;
}
/**
* @return the bean
*/
public String getBean() {
return bean;
}
/**
* @param bean the bean to set
*/
public void setBean(String bean) {
this.bean = bean;
}
/**
* @return the url
*/
public String getUrl() {
return url;
}
/**
* @param url the url to set
*/
public void setUrl(String url) {
this.url = url;
}
public void setNumber(int number) {
this.number = number;
}
}
3.page.java
package oranges.util;
import java.util.List;
public class Page<T> {
private int total; //總的記錄數
private int page; //當前頁數
private int size; //每頁的記錄數
private List<T> rows; //每頁資料的集合
public int getTotal() {
return total;
}
public void setTotal(int total) {
this.total = total;
}
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
public List<T> getRows() {
return rows;
}
public void setRows(List<T> rows) {
this.rows = rows;
}
}
4.頁面資料
<%@ taglib prefix="oranges" uri="http://oranges.cn/common/"%>
<div class="col-md-12 text-right">
<oranges:page url="${pageContext.request.contextPath }/customer/list.action" />
</div>