General paging (2)

Catalog

Preface

One 、pageBean Perfection of

Two 、PageTag The implementation of the

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Preface

Last time we shared the common paging （1）, The content shared today is general paging （2）. The content of this article is based on the previous article

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One 、pageBean Perfection of

analysis ：

  Yes pagebean To initialize

initialization jsp The current page passed from the page

initialization jsp The page size passed from the page

initialization jsp Whether pages are paged after being transferred

Keep the last query request

Keep the last query criteria

package com.zhw.util;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

public class PageBean {
	private int page = 1;//  Page number 

	private int rows = 10;//  Page size 

	private int total = 0;//  Total number of records 

	private boolean pagination = true;//  Pagination or not 
	
	private String url;
	
	// Save last query criteria 
	private Map<String, String[]> parmeterMap = new HashMap<String, String[]>();

	// Get the maximum page number 
	public int maxPage() {
		return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows + 1;
	}
	
	// Get the page number of the previous page 
	public int previousPage() {
		return this.page > 1 ? this.page -1 : this.page;
	}
	
	// Gets the page number of the next page 
	public int nextPage() {
		return this.page<this.maxPage() ? this.page +1 : this.page;
	}
	
	// initialization pagebean
	public void setRequest(HttpServletRequest req) {
		this.setPage(req.getParameter("page"));
		this.setRows(req.getParameter("rows"));
		this.setPagination(req.getParameter("pagination"));
		this.setUrl(req.getRequestURL().toString());
		this.setParmeterMap(req.getParameterMap());
	}
	private void setPage(String page) {
		if(StringUtils.isNotBlank(page)) {
			//set Automatic generation method 
			this.setPage(Integer.valueOf(page));
		}
		
	}
	
	private void setPagination(String pagination) {
		if(StringUtils.isNotBlank(pagination)) {
			this.setPagination(!"false".equals(pagination));
		}
	}
	
	private void setRows(String rows) {
		if(StringUtils.isNotBlank(rows)) {
			this.setRows(Integer.valueOf(rows));
		}
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public Map<String, String[]> getParmeterMap() {
		return parmeterMap;
	}

	public void setParmeterMap(Map<String, String[]> parmeterMap) {
		this.parmeterMap = parmeterMap;
	}

	public PageBean() {
		super();
	}

	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;
	}

	/**
	 *  Get the subscript of the starting record 
	 * 
	 * @return
	 */
	public int getStartIndex() {
		return (this.page - 1) * this.rows;
	}

	@Override
	public String toString() {
		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination
				+ ", url=" + url + ", parmeterMap=" + parmeterMap + "]";
	}

}

Two 、PageTag The implementation of the

package com.zhw.tag;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;

import com.zhw.util.PageBean;

public class PageTag extends BodyTagSupport{
	private PageBean pagebean;
	
	
	
	public PageBean getPagebean() {
		return pagebean;
	}

	public void setPagebean(PageBean pagebean) {
		this.pagebean = pagebean;
	}

	@Override
	public int doStartTag() throws JspException {
		JspWriter out = pageContext.getOut();
		try {
			out.print(toHTML());
		} catch (Exception e) {
			e.printStackTrace();
		}
		return super.doStartTag();
	}

	private Object toHTML() {
		StringBuffer sb = new StringBuffer();
		
		sb.append("<form action='"+pagebean.getUrl()+"' id='pageBeanForm' method='post'>");
		sb.append("	<input type='hidden' name='page'>");
		Map<String, String[]> parmeterMap = pagebean.getParameterMap();
		if(parmeterMap != null && parmeterMap.size()>0) {
			Set<Entry<String, String[]>> entrySet = parmeterMap.entrySet();
			for (Entry<String, String[]> entry : entrySet) {
				String key = entry.getKey();
				String[] value = entry.getValue();
				if(!"page".equals(key)) {
					for (String string : value) {
						sb.append("	<input type='hidden' name='"+key+"' value='"+value+"'>");
					}
				}
			}
		}
		sb.append("</form>");
		sb.append("<ul class='pagination justify-content-center'>");
		sb.append(" <li class='page-item'><a class='page-link'");
		sb.append("     href='javascript:gotoPage(1)'> home page </a></li>");
		sb.append("	<li class='page-item'><a class='page-link'");
		sb.append("		href='javascript:gotoPage("+pagebean.previousPage()+")'>&lt;</a></li>");
		sb.append("	<li class='page-item'><a class='page-link' href='#'>"+pagebean.getPage()+"</a></li>");
		sb.append(" <li class='page-item "+(pagebean.getPage() == pagebean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pagebean.nextPage()+")'>&gt;</a></li>");
		sb.append("	<li class='page-item "+(pagebean.getPage() == pagebean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pagebean.maxPage()+")'> Tail page </a></li>");
		sb.append("	<li class='page-item go-input'><b> To the first </b><input class='page-link'");
		sb.append("		type='text' id='skipPage' name='' /><b> page </b></li>");
		sb.append("	<li class='page-item go'><a class='page-link'");
		sb.append("		href='javascript:skipPage()'> determine </a></li>");
		sb.append("	<li class='page-item'><b> common "+pagebean.getTotal()+" strip </b></li>");
		sb.append("</ul>");
		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");
		sb.append("				|| parseInt(page) > "+pagebean.maxPage()+") {");
		sb.append("			alert(' Please enter 1~"+pagebean.maxPage()+" The number of ');");
		sb.append("			return;");
		sb.append("		}");
		sb.append("		gotoPage(page);");
		sb.append("	}");
		sb.append("</script>");
		
		return sb;
	}
}

Servlet：

package com.zhw.web;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.zhw.dao.BookDao;
import com.zhw.entity.Book;
import com.zhw.util.PageBean;

@WebServlet("/book/search")
public class BookServlet extends HttpServlet{
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		BookDao bookDao = new BookDao();
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
		Book book = new Book();
		book.setBname(req.getParameter("bname"));
		try {
			List<Book> list = bookDao.list(book , pageBean);
			req.setAttribute("books", list);
			req.setAttribute("pageBean", pageBean);
			req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

 

 

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