Servlet pager 封装分页控件

谁践踏了优雅 2022-02-23 05:44 234阅读 0赞

Servlet 目录：  
![在这里插入图片描述][2019040622103636.]

web目录：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hzbDA1MzBoc2w_size_16_color_FFFFFF_t_70]

### 1、Person 实体类 ###

package com.java.servlet.pager;
    
    public class Person { 
    	private String id;
    	private String name;
    	private int age;
    	private String sex;
    	private String address;
    	private String demo;
    	
    	public Person() { 
    	}
    	
    	public Person(String id, String name, int age, String sex, String address, String demo) { 
    		this();
    		this.id = id;
    		this.name = name;
    		this.age = age;
    		this.sex = sex;
    		this.address = address;
    		this.demo = demo;
    	}
    	public Person(String id, String name, int age, String sex, String address) { 
    		this(id, name, age, sex, address, "");
    	}
    	public Person(String id, String name, int age, String sex) { 
    		this(id, name, age, sex, "");
    	}
    	
    	
    	public String getId() { 
    		return id;
    	}
    	public void setId(String id) { 
    		this.id = id;
    	}
    	public String getName() { 
    		return name;
    	}
    	public void setName(String name) { 
    		this.name = name;
    	}
    	public int getAge() { 
    		return age;
    	}
    	public void setAge(int age) { 
    		this.age = age;
    	}
    	public String getSex() { 
    		return sex;
    	}
    	public void setSex(String sex) { 
    		this.sex = sex;
    	}
    	public String getAddress() { 
    		return address;
    	}
    	public void setAddress(String address) { 
    		this.address = address;
    	}
    	public String getDemo() { 
    		return demo;
    	}
    	public void setDemo(String demo) { 
    		this.demo = demo;
    	}
    	
    	@Override
    	public String toString() { 
    		return "Person [name=" + name + ", age=" + age + ", sex=" + sex + ", address=" + address + ", demo=" + demo
    				+ "]";
    	}
    }

### 2、PagerServlet 模拟逻辑处理类 ###

package com.java.servlet.pager;
    
    import java.lang.reflect.Method;
    import java.util.ArrayList;
    import java.util.List;
    
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.commons.lang.StringUtils;
    
    public class PagerServlet extends HttpServlet { 
    
    	private static final long serialVersionUID = 1L;
    
    	@SuppressWarnings("unused")
    	private void list(HttpServletRequest req, HttpServletResponse res) { 
    		List<Person> persons = new ArrayList<Person>();
    		for (int i = 1; i < 30; i++) { 
    			persons.add(new Person(String.valueOf(i), "name_" + i, 10 + i, (i % 2 == 0 ? "男" : "女"), "address_" + i, "demo_" + i));
    		}
    		String name = req.getParameter("name");
    		req.setAttribute("name", name);
    		String sex = req.getParameter("sex");
    		req.setAttribute("sex", sex);
    		for (int j = 0; j < persons.size(); j++) { 
    			if (StringUtils.isNotEmpty(name) && !persons.get(j).getName().contains(name)) { 
    				persons.remove(j);
    				j--;
    				continue;
    			}
    			if (StringUtils.isNotEmpty(sex)) { 
    				if ("1".equals(sex) && "女".equals(persons.get(j).getSex())) { 
    					persons.remove(j);
    					j--;
    					continue;
    				} else if ("2".equals(sex) && "男".equals(persons.get(j).getSex())) { 
    					persons.remove(j);
    					j--;
    					continue;
    				}
    			}
    		}
    		
    		int curPage = req.getParameter("curPage") == null ? 1 : Integer.parseInt(req.getParameter("curPage"));
    		if (curPage == 0) { 
    			curPage = 1;
    			req.setAttribute("curPage", curPage);
    		}
    		
    		int pageSize = 2;
    		req.setAttribute("pageSize", pageSize);
    		req.setAttribute("total", persons.size());
    		req.setAttribute("curPage", curPage);
    		if (persons.size() > 2) { 
    			int lastIdx = curPage * pageSize;
    			if (lastIdx >= persons.size()) { 
    				lastIdx = persons.size();
    			}
    			persons = persons.subList((curPage - 1) * pageSize, lastIdx);
    		}
    		
    		req.setAttribute("persons", persons);
    		try { 
    			//res.sendRedirect("pager.jsp"); //重定向不能带requset参数
    			req.getRequestDispatcher("pager.jsp").forward(req, res);
    		} catch (Exception e) { 
    			e.printStackTrace();
    		}
    	}
    	
    	@Override
    	protected void service(HttpServletRequest req, HttpServletResponse resp) { 
    		
    		String methodName = req.getParameter("method");
    		try { 
    			Method method = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
    			method.setAccessible(true);
    			method.invoke(this, req, resp);
    		} catch (Exception e) { 
    			e.printStackTrace();
    		}
    	}
    }

### 3、PagerTag Tag处理类 ###

package com.java.servlet.pager;
    
    import java.io.IOException;
    
    import javax.servlet.jsp.JspException;
    import javax.servlet.jsp.tagext.BodyTagSupport;
    import javax.servlet.jsp.tagext.Tag;
    
    public class PagerTag extends BodyTagSupport { 
    
    	private static final long serialVersionUID = -1848984466240909235L;
    	
    	private int total;
    	private int pageSize;
    	private int curPage;
    	
    	@Override
    	public int doStartTag() throws JspException { 
    		
    		if (pageSize == 0) { 
    			System.out.println("Page size 不能为空！");
    			return Tag.SKIP_BODY;
    		}
    		
    		//默认为第一页
    		if (curPage == 0) { 
    			curPage = 1;
    		}
    		
    		//没有分页时，设置为不可用
    		String navDisableStyle = "";
    		if (total == 0) { 
    			navDisableStyle = " disabled=\"disabled\"";
    		}
    		
    		int pageNum = (int) Math.ceil((double)total / pageSize);
    		System.out.println(pageNum);
    		String forwardClass = "";
    		if (curPage == pageNum) { 
    			forwardClass = "class='disabled'";
    		}
    		
    		String backClass = "";
    		if (curPage == 1) { 
    			backClass = "class='disabled'";
    		}
    		StringBuilder sb = new StringBuilder();
    		sb.append("<nav aria-label=\"Page navigation\"" + navDisableStyle + ">\r\n" + 
    				" <ul class=\"pagination\">\r\n" + 
    				" <li " + backClass + ">\r\n" + 
    				" <a href=\"javascript:doPage(1)\" aria-label=\"First\">\r\n" + 
    				" <span aria-hidden=\"true\">«</span>\r\n" + 
    				" </a>\r\n" + 
    				" </li>" +
    				" <li " + backClass + ">\r\n" + 
    				" <a href=\"javascript:doPage(" + (curPage - 1) + ")\" aria-label=\"Previous\" style=\"padding: 11px 13px 8px 13px;\" >\r\n" + 
    				" <span aria-hidden=\"true\" style=\"font-family: cursive;font-size: 11px; font-weight: bold;\"><</span>\r\n" + 
    				" </a>\r\n" + 
    				" </li>");
    		
    		if (pageNum > 14) { 
    			if (curPage < 8) { 
    				for (int i = 1; i < 8; i++) { 
    					if (i == curPage) { 
    						sb.append("<li class='active'><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    						continue;
    					}
    					
    					sb.append("<li><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    				}
    
    				sb.append("<li class='disabled'><a href=\"javascript:void(0)\">•••</a></li>");
    				
    				for (int i = pageNum - 7; i <= pageNum; i++) { 
    					if (i == curPage) { 
    						sb.append("<li class='active'><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    						continue;
    					}
    					
    					sb.append("<li><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    				}
    			} else { 
    				sb.append("<li class='disabled'><a href=\"javascript:void(0)\">•••</a></li>");
    				
    				for (int i = pageNum - 14; i <= pageNum; i++) { 
    					if (i == curPage) { 
    						sb.append("<li class='active'><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    						continue;
    					}
    					
    					sb.append("<li><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    				}
    			}
    		} else { 
    			for (int i = 1; i <= pageNum; i++) { 
    				
    				if (i == curPage) { 
    					sb.append("<li class='active'><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    					continue;
    				}
    				
    				sb.append("<li><a href=\"javascript:doPage(" + i + ")\">" + i + "</a></li>");
    			}
    		}
    		
    		sb.append(" <li " + forwardClass + ">\r\n" + 
    				" <a href=\"javascript:doPage(" + (curPage + 1) + ")\" aria-label=\"Next\" style=\"padding: 11px 13px 8px 13px;\">\r\n" + 
    				" <span aria-hidden=\"true\" style=\"font-family: cursive;font-size: 11px; font-weight: bold;\">></span>\r\n" + 
    				" </a>\r\n" + 
    				" </li>\r\n" + 
    				" <li " + forwardClass + ">\r\n" +
    				" <a href=\"javascript:doPage(" + pageNum + ")\" aria-label=\"Last\">\r\n" + 
    				" <span aria-hidden=\"true\">»</span>\r\n" + 
    				" </a>\r\n" + 
    				" </li>\r\n" + 
    				" </ul>\r\n" + 
    				"</nav>");
    		
    		sb.append("<script type=\"text/javascript\">\r\n" + 
    				" function doPage(page){\r\n" + 
    				" if((page >= " + pageNum + " && " + (curPage == pageNum) + ") || (page <= 1 && " + curPage + " == 1)) {" +
    				" return;" +
    				" }" +
    				" $(\"#curPage\").val(page);\r\n" + 
    				" document.forms[0].submit();\r\n" + 
    				" }\r\n" + 
    				" </script>");
    		try { 
    			this.pageContext.getOut().print(sb.toString());
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    		return Tag.SKIP_BODY;
    		//return Tag.EVAL_BODY_INCLUDE; //执行标签中的内容
    	}
    
    	public int getTotal() { 
    		return total;
    	}
    
    	public void setTotal(int total) { 
    		this.total = total;
    	}
    
    	public int getPageSize() { 
    		return pageSize;
    	}
    
    	public void setPageSize(int pageSize) { 
    		this.pageSize = pageSize;
    	}
    
    	public int getCurPage() { 
    		return curPage;
    	}
    
    	public void setCurPage(int curPage) { 
    		this.curPage = curPage;
    	}
    	
    }

页面中有使用到Bootstrap中的一些样式，自行网上下载。

### 4、pager.tld 定义标签 ###

<?xml version="1.0" encoding="UTF-8" ?>
    
    <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0">
        
     <description>Show pager navigator</description>
     <display-name>Pager navigator</display-name>
     <tlib-version>1.1</tlib-version>
     <short-name>p</short-name>
     <uri>http://com.hsl.pager/core</uri>
     <tag>
     <name>pager</name>
     <tag-class>com.java.servlet.pager.PagerTag</tag-class>
     <body-content>empty</body-content>
     <attribute>
      <description>Data size</description>
      <name>total</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
     </attribute>
     <attribute>
      <description>Page size</description>
      <name>pageSize</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
     </attribute>
     <attribute>
      <description>Current page number</description>
      <name>curPage</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
     </attribute>
     </tag>
    </taglib>

### 5、web.xml 配置Servlet ###

<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="3.0" 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-app_3_0.xsd">
      <display-name></display-name>
      
      <servlet>
        <servlet-name>PagerServlet</servlet-name>
        <servlet-class>com.java.servlet.pager.PagerServlet</servlet-class>
      </servlet>
      	
      <servlet-mapping>
        <servlet-name>PagerServlet</servlet-name>
        <url-pattern>/pager.do</url-pattern>
      </servlet-mapping>
      
      <welcome-file-list>
        <welcome-file>pager.jsp</welcome-file>
      </welcome-file-list>
    </web-app>

### 6、pager.jsp 页面 ###

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
    <%@ taglib uri="http://com.hsl.pager/core" prefix="p" %>
    <%
    	String path = request.getContextPath();
    	String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
    			+ path + "/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
    <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'Pager.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <link rel="stylesheet" type="text/css" href="./css/lib/bootstrap.min.css">
    <link rel="stylesheet" type="text/css" href="./css/lib/bootstrap-theme.min.css">
    <script type="text/javascript" src="./js/lib/jquery-3.3.1.js"></script>
    <script type="text/javascript" src="./js/lib/bootstrap.js"></script>
    </head>
    <body>
    	<fieldset style="margin: 10px;">
    		<legend>Person信息列表:</legend>
    
    		<form class="form-inline">
    			<div class="form-group">
    				<label for="name">姓名</label> <input type="text" class="form-control" id="name" name="name" value="${name}" placeholder="请输入姓名：">
    			</div>
    			<div class="form-group">
    				<label for="sex">性别</label>
    				<select name="sex" id="sex" class="form-control" >
    					<option value="0"></option>
    					<c:choose>
    						<c:when test="${sex == '1'}">
    							<option value="1" selected = "selected">男</option>
    							<option value="2">女</option>
    						</c:when>
    						<c:when test="${sex == '2'}">
    							<option value="1">男</option>
    							<option value="2" selected = "selected">女</option>
    						</c:when>
    						<c:otherwise>
    							<option value="1">男</option>
    							<option value="2">女</option>
    						</c:otherwise>
    					</c:choose>
    				</select>
    			</div>
    			<input type="hidden" name="curPage" value="1" id="curPage">
    			<input type="hidden" name="method" value="list">
    			<button type="submit" class="btn btn-default">查询</button>
    		</form>
    
    		<table class="table table-striped table-bordered">
    			<thead>
    				<tr>
    					<th>序号</th>
    					<th>姓名</th>
    					<th>年龄</th>
    					<th>性别</th>
    					<th>地址</th>
    					<th>备注</th>
    				</tr>
    			</thead>
    			<tbody>
    				<c:forEach items="${persons}" var="person" varStatus="s">
    					<tr>
    						<td>${s.index}</td>
    						<td>${person.name}</td>
    						<td>${person.age}</td>
    						<td>${person.sex}</td>
    						<td>${person.address}</td>
    						<td>${person.demo}</td>
    					</tr>
    				</c:forEach>
    				<tr>
    					<td colspan="6" style="text-align: right;">
    						<p:pager pageSize="${pageSize}" curPage="${curPage}" total="${total}"/>
    					</td>
    				</tr>
    			</tbody>
    		</table>
    	</fieldset>
    	
    	
    </body>
    </html>

页面中有使用到 jstl-api-1.2.jar 标准标签库，请自行下载。

### 7、跑出的页面效果如下 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hzbDA1MzBoc2w_size_16_color_FFFFFF_t_70 1]

[2019040622103636.]: /images/20220223/7ed6083ace0a44aeaeb83f8f7240552e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hzbDA1MzBoc2w_size_16_color_FFFFFF_t_70]: /images/20220223/f812475707854a19aa8ff1af74b8922e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hzbDA1MzBoc2w_size_16_color_FFFFFF_t_70 1]: /images/20220223/4f2ac266eec74bd6aac42b200832d15b.png