通用分页一 已经把数据展示到页面上,并且能够按代码来规定查询多少条,
这次就就以a标签的形式,由用户来进行分页,
具体的思路
1、 对pagebean增强(添加url、paramMap属性,添加初始化pagebean的方法、最大页、上一页、下一页方法)
2、 将按钮条写入标签助手类
3、 将隐藏的form表单写入标签助手类
4、 将对应的js代码写入标签助手类
5、 测试通用分页是否完善
- 需要的类
-
PageBean BookServlet PageTag bookList
标签描述文件 z.tld
先把PageBean需要的方法写好
public class PageBean {
private int page = 1;// 页码
private int rows = 10;// 页大小
private int total = 0;// 总记录数
private boolean pagination = true;// 是否分页
private String url;
private Map<String, String[]> paramMap = new HashMap<>();
public void setRequest(HttpServletRequest req) {
this.setPage(req.getParameter("page"));
this.setRows(req.getParameter("rows"));
this.setPagination(req.getParameter("pagination"));
// getRequestURL获取到浏览器请求的全路径
this.setUrl(req.getRequestURL().toString());
// getParameterMap可以获取到一次url请求所携带的所有参数
this.setParamMap(req.getParameterMap());
}
public void setPagination(String pagination) {
if (StringUtils.isNotBlank(pagination)) {
this.setPagination(!"false".equals(pagination));
}
}
public void setRows(String rows) {
if (StringUtils.isNotBlank(rows))
this.setRows(Integer.valueOf(rows));
}
public void setPage(String page) {
if (StringUtils.isNotBlank(page)) {
this.setPage(Integer.valueOf(page));
}
}
public PageBean() {
super();
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public Map<String, String[]> getParamMap() {
return paramMap;
}
public void setParamMap(Map<String, String[]> paramMap) {
this.paramMap = paramMap;
}
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public int getRows() {
return rows;
}
public void setRows(int rows) {
this.rows = rows;
}
public int getTotal() {
return total;
}
public void setTotal(int total) {
this.total = total;
}
public void setTotal(String total) {
this.total = Integer.parseInt(total);
}
public boolean isPagination() {
return pagination;
}
public void setPagination(boolean pagination) {
this.pagination = pagination;
}
/**
* 获得起始记录的下标
*
* @return
*/
public int getStartIndex() {
return (this.page - 1) * this.rows;
}
@Override
public String toString() {
return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
}
/**
* 获取到总页数
* @return
*/
public int getMaxPage() {
return this.total % this.rows == 0 ?
this.total / this.rows :
(this.total / this.rows) + 1;
}
/**
* 获取下一页页码
* @return
*/
public int getNextPage() {
return this.page < this.getMaxPage() ? this.page+1 : this.page;
}
/**
* 获取上一页页码
* @return
*/
public int getPreviousPage() {
return this.page > 1 ? this.page-1 : this.page;
}
接下来就要写助手类,PageTag
public class PageTag extends BodyTagSupport {
private static final long serialVersionUID = 602917970858963475L;
private PageBean pageBean;
@Override
public int doStartTag() throws JspException {
JspWriter out = pageContext.getOut();
try {
out.print(toHTML());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return super.doStartTag();
}
public String toHTML() {
StringBuffer sb=new StringBuffer();
//下一次请求提交到后台的表单html代码拼接
sb.append("<form id='pageBeanForm' action='"+pageBean.getUrl()+"' method='post'>");
Map<String, String[]> paramMap = pageBean.getParamMap();
if(paramMap!=null&¶mMap.size()>0) {
for (Entry<String, String[]> entry : paramMap.entrySet()) {
if(!"page".equals(entry.getKey())) {
for (String val : entry.getValue()) {
sb.append("<input type='hidden' name='"+entry.getKey()+"' value='"+val+"'>");
}
}
}
}
sb.append("<input type='hidden' name='page'>");
sb.append("</from>");
//分页条html代码拼接
sb.append("<div style='text-align: right; font-size: 12px;'>");
sb.append(" 每页"+pageBean.getRows()+"条,共"+pageBean.getTotal()+"条,第"+pageBean.getPage()+"页,共"+pageBean.getMaxPage()+"页 <a");
sb.append(" href='javascript:gotoPage(1)'>首页</a> <a");
sb.append(" href='javascript:gotoPage("+pageBean.getPreviousPage()+")'>上一页</a> <a");
sb.append(" href='javascript:gotoPage("+pageBean.getNextPage()+")'>下一页</a> <a");
sb.append(" href='javascript:gotoPage("+pageBean.getMaxPage()+")'>尾页</a> <input type='text'");
sb.append(" id='skipPage'");
sb.append(" style='text-align: center; font-size: 12px; width: 50px;'> <a");
sb.append(" href='javascript:skipPage()'>Go</a>");
sb.append("</div>");
//分页所需要调用的js代码
sb.append("<script type='text/javascript'>");
sb.append(" function gotoPage(page) {");
sb.append(" document.getElementById('pageBeanForm').page.value = page;");
sb.append(" document.getElementById('pageBeanForm').submit();");
sb.append(" }");
sb.append(" function skipPage() {");
sb.append(" var page = document.getElementById('skipPage').value;");
sb.append(" if(!page || isNaN(page) || parseInt(page)<1 || parseInt(page)>"+pageBean.getMaxPage()+"){");
sb.append(" alert('请输入1~N的数字');");
sb.append(" return;");
sb.append(" }");
sb.append(" gotoPage(page);");
sb.append(" }");
sb.append("</script>");
return null;
}
public PageBean getPageBean() {
return pageBean;
}
public void setPageBean(PageBean pageBean) {
this.pageBean = pageBean;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
public PageTag() {
super();
}
}
在写标签描述文件 tld,去写个标签,
<description>zking 1.1 core library</description>
<display-name>zking core</display-name>
<tlib-version>1.1</tlib-version>
<short-name>z</short-name>
<uri>/zking</uri>
<tag>
<name>page</name>
<tag-class>com.tzp.tags.PageTag</tag-class>
<body-content>JSP</body-content>
<attribute>
<name>pageBean</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
控制类 BookServlet
public class BookServlet extends HttpServlet {
private BookDao bd=new BookDao();
private static final long serialVersionUID = 7111447857696817024L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String bname=req.getParameter("bname");
Book book=new Book();
book.setBname(bname);
PageBean pagebean=new PageBean();
pagebean.setRequest(req);
try {
// 查询出符合条件的某一页的记录数
List<Book> list = bd.list(book, pagebean);
req.setAttribute("bookList", list);
req.setAttribute("pagebean",pagebean);
req.getRequestDispatcher("bookList.jsp").forward(req, resp);
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
最后展示到页面 调用标签了进行展示到页面
记得要引用标签
<%@ taglib uri="/zking" prefix="z" %>
下面的分页a标签都是可以进行使用了