SSM —— Jstl自制分頁標籤
阿新 • • 發佈：2018-12-11
首先需要兩個實體工具類
page省略get和set
public class Page<T> {
private int total; // 總條數
private int page; // 當前頁
private int size; // 每頁數
private List<T> rows; // 結果集
}
NavigationTag
package com.etc.utils; 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; /** * 顯示格式：首頁 上一頁 1 2 3 4 5下一頁 尾頁 */ 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\">"); //首頁連結路徑 String homeUrl = append(url, "page", 1); //末頁連結路徑 String backUrl = append(url, "page", pageCount); // 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=\"" + homeUrl + "\">" + "首頁</a></li>"); writer.print("<li><a href=\"" + preUrl + "\">" + "上一頁</a></li>"); } else { writer.print("<li class=\"disabled\"><a href=\"#\">" + "首頁 </a></li>"); 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 =1; if(page.getPage() - 2 <=0){ indexPage=1; }else if(pageCount-page.getPage() <=2){ indexPage=pageCount-4; }else{ indexPage= page.getPage() - 2; } for (int i= 1;i <= number && indexPage <= pageCount;indexPage++,i++){ if (indexPage == page.getPage()) { writer.print("<li class=\"active\"><a href=\"#\">" + indexPage +"<spanclass=\"sr-only\"></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>"); writer.print("<li><a href=\"" + backUrl + "\">" + "尾頁</a></li>"); } else { writer.print("<li class=\"disabled\"><a href=\"#\">" + "下一頁</a></li>"); writer.print("<li class=\"disabled\"><a href=\"#\">" + "尾頁</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 */ 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 */ private String resolveUrl(String url, javax.servlet.jsp.PageContext pageContext) throws JspException { 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; } public String getBean() { return bean; } public void setBean(String bean) { this.bean = bean; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public void setNumber(int number) { this.number = number; } }
commons.tld檔案
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <!-- 指定標籤庫的版本號 --> <tlib-version>2.0</tlib-version> <!-- 指定JSP的版本號 --> <jsp-version>1.2</jsp-version> <!-- 指定標籤庫的名稱 --> <short-name>common</short-name> <!-- 指定標籤庫的URI --> <uri>http://mypageutil.com/common/</uri> <!-- 指定標籤庫的顯示名稱 --> <display-name>Common Tag</display-name> <!-- 指定標籤庫的描述 --> <description>Common Tag library</description> <!-- 註冊一個自定義標籤 --> <tag> <!-- 指定註冊的自定義標籤名稱 --> <name>page</name> <!-- 指定自定義標籤的標籤處理器類 --> <tag-class>com.etc.utils.NavigationTag</tag-class> <!-- 指定標籤體型別 --> <body-content>JSP</body-content> <!-- 描述 --> <description>create navigation for paging</description> <!-- 指定標籤中的屬性 --> <attribute> <!-- 指定屬性名稱 --> <name>url</name> <!-- 該屬性為true時表示其指定是屬性為必須屬性 --> <required>true</required> <!-- 該屬性用於指定能不能使用表示式來動態指定資料，為true時表示可以 --> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>bean</name> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>number</name> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
mapper.xml
<!--SQL片段 --> <sql id="selectStudentListWhere"> <where> <if test="username != null" > username like "%"#{username}"%" </if> <if test="password != null" > OR password like "%"#{password}"%" </if> <if test="major != null" > OR major like "%"#{major}"%" </if> </where> </sql> <!-- 查詢客戶列表 --> <select id="selectStudentList" parameterType="com.etc.entity.Student" resultType="com.etc.entity.Student"> select id, username, password,major from t_student <include refid="selectStudentListWhere"/> <!-- 執行分頁查詢 --> <if test="start !=null and rows != null"> limit #{start},#{rows} </if> </select> <!-- 查詢客戶總數 --> <select id="selectStudentListCount" parameterType="com.etc.entity.Student" resultType="Integer"> select count(*) from t_student <include refid="selectStudentListWhere"/> </select>
Dao
// 客戶列表
public List<Student> selectStudentList(Student student);
// 客戶數
public Integer selectStudentListCount(Student student);service實現類
public Page<Student> queryAllByJstl(Integer page, Integer rows, String username, String password) {
// 建立客戶物件
Student student = new Student();
// 判斷客戶名稱
if(StringUtils.isNotBlank(username)){
student.setUsername(username);
}
// 判斷客戶資訊來源
if(StringUtils.isNotBlank(password)){
student.setPassword(password);
}
// 當前頁
student.setStart((page-1) * rows) ;
// 每頁數
student.setRows(rows);
// 查詢客戶列表
List<Student> students =
mapper.selectStudentList(student);
// 查詢客戶列表總記錄數
Integer count = mapper.selectStudentListCount(student);
// 建立Page返回物件
Page<Student> result = new Page<>();
result.setPage(page);
result.setRows(students);
result.setSize(rows);
result.setTotal(count);
return result;
}controler
@RequestMapping("/queryAllByJstl")
public String list(@RequestParam(defaultValue="1")Integer page,
@RequestParam(defaultValue="5")Integer rows,
String username,String password, Model model) {
// 條件查詢所有客戶
Page<Student> studentPage = service.queryAllByJstl(page, rows, username,password);
model.addAttribute("page", studentPage);
return "queryAllByJstl";
}Student省略get和set
private Integer id;
private String username;
private String password;
private String major;
private Integer start; // 起始行
private Integer rows; // 所取行數
jsp頁面引用
<%@ taglib prefix="itheima" uri="http://mypageutil.com/common/" %><style>
#mypage li{
float: left;
margin-left:6px;
list-style: none;
}
</style><form method="post">
<table>
<tr>
<th>姓名</th>
<th>密碼</th>
<th>專業</th>
</tr>
<c:forEach var="c" items="${page.rows}">
<tr>
<td>${c.username}</td>
<td>${c.password}</td>
<td>${c.major}</td>
</tr>
</c:forEach>
</table>
</form>
<div id="mypage">
<itheima:page url="${pageContext.request.contextPath}/queryAllByJstl" />
</div>實現效果
