pagehelper的使用和一些坑！
阿新 • • 發佈：2020-07-30
目錄
1.1 pagehelper介紹和使用
PageHelper是一款好用的開源免費的Mybatis第三方物理分頁外掛。
原本以為分頁外掛，應該是很簡單的，然而PageHelper比我想象的要複雜許多，它做的很強大，也很徹底，強大到使用者可能並不需要這麼多功能，徹底到一參可以兩用。
1.1.1 springboot下使用
- 依賴包匯入（這裡劃重點！！！有坑！！）
<dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper</artifactId> <version>最新版本</version> </dependency>
這是從官網上的標準形式，但是注意了。pagehelper與springboot整合的話，不能用這個包，這樣會導致分頁失效！
正確的是下面這種匯入方式：
<dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.2.3</version> </dependency>
可以看到跟springboot整合的包大多數後面都是以spring-boot-starter結尾。。。。
剛開始我用的第一種，程式碼也全都正確，就是沒有分頁效果。。。這坑！！
- User
public class User { private Integer id; @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", password='" + password + '\'' + ", uid=" + uid + ", admin=" + admin + ", email='" + email + '\'' + ", phonenumber=" + phonenumber + ", classid=" + classid + '}'; } private String name; private String password; private Integer uid; private Integer admin; private String email; private Integer phonenumber; private Integer classid; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name == null ? null : name.trim(); } public String getPassword() { return password; } public void setPassword(String password) { this.password = password == null ? null : password.trim(); } public Integer getUid() { return uid; } public void setUid(Integer uid) { this.uid = uid; } public Integer getAdmin() { return admin; } public void setAdmin(Integer admin) { this.admin = admin; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email == null ? null : email.trim(); } public Integer getPhonenumber() { return phonenumber; } public void setPhonenumber(Integer phonenumber) { this.phonenumber = phonenumber; } public Integer getClassid() { return classid; } public void setClassid(Integer classid) { this.classid = classid; } }
- UserMapper
@Repository
public interface UserMapper {
long countByExample(UserExample example);
int deleteByExample(UserExample example);
int insert(User record);
int insertSelective(User record);
List<User> selectAllUser();
User selectByExample(UserExample example);
User selectBynameANDpassword(String name,String password);
int updateByExampleSelective(@Param("record") User record, @Param("example") UserExample example);
int updateByExample(@Param("record") User record, @Param("example") UserExample example);
}
這裡只用selectAllUser()這個方法就行了！
-
UserMapper.xml
鄙人還是比較喜歡這種xml的方式宣告sql，並不是覺得註解的不好，只是覺得這種方式使得程式碼的整體可讀性更好！
- controller
//測試分頁資訊
@RequestMapping("/UserInfo")
public String presentUser(Model model,
@RequestParam(required = false,defaultValue="1",value="pageNum")Integer pageNum,
@RequestParam(defaultValue="2",value="pageSize")Integer pageSize)throws Exception {
if(pageNum == null){
pageNum = 1; //設定預設當前頁
}
if(pageNum <= 0){
pageNum = 1;
}
if(pageSize == null){
pageSize = 2; //設定預設每頁顯示的資料數
}
System.out.println("當前頁是："+pageNum+"顯示條數是："+pageSize);
//1.引入分頁外掛,pageNum是第幾頁，pageSize是每頁顯示多少條,預設查詢總數count
//2.緊跟的查詢就是一個分頁查詢-必須緊跟.後面的其他查詢不會被分頁，除非再次呼叫PageHelper.startPage
PageHelper.startPage(pageNum,pageSize);
List<User> userList =pageimpl.getAllUser();
System.out.println("分頁資料："+userList);
//3.使用PageInfo包裝查詢後的結果,5是連續 顯示的條數,結果list型別是Page<E>
PageInfo<User> pageInfo = new PageInfo<User>(userList,pageSize);
//4.使用model/map/modelandview等帶回前端
model.addAttribute("pageInfo",pageInfo);
return "bootstraptable";
}
- 前端
<!doctype html>
<html lang="en" xmlns:th="http://www.thymeleaf.org" xmlns:c="http://www.w3.org/1999/xhtml">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Hello, Bootstrap Table!</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous">
<link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/bootstrap-table.min.css">
</head>
<body>
<table data-toggle="table">
<thead>
<tr>
<th>name</th>
<th>password</th>
<th>uid</th>
</tr>
</thead>
<tbody >
<tr th:each="c:${pageInfo.list}">
<td>[[${c.name}]]</td>
<td>[[${c.password}]]</td>
<td>[[${c.uid}]]</td>
</tr>
</tbody>
</table>
<br/>
<div class="modal-footer no-margin-top">
<div class="col-md-6">
當前第 [[${pageInfo.pageNum}]]頁,共 [[${pageInfo.pages}]] 頁.一共 [[${pageInfo.total}]] 條記錄
</div>
<ul class="pagination pull-right no-margin">
<li th:if="${pageInfo.hasPreviousPage}">
<a th:href="'/UserInfo?pageNum=1'">首頁</a>
</li>
<li class="prev" th:if="${pageInfo.hasPreviousPage}">
<a th:href="'/UserInfo?pageNum='+${pageInfo.prePage}">
<i class="ace-icon fa fa-angle-double-left"></i>
</a>
</li>
<!--遍歷條數-->
<li th:each="nav:${pageInfo.navigatepageNums}">
<a th:href="'/UserInfo?pageNum='+${nav}" th:text="${nav}" th:if="${nav != pageInfo.pageNum}"></a>
<span style="font-weight: bold;background: #6faed9;" th:if="${nav == pageInfo.pageNum}" th:text="${nav}" ></span>
</li>
<li class="next" th:if="${pageInfo.hasNextPage}">
<a th:href="'/UserInfo?pageNum='+${pageInfo.nextPage}">
<i class="ace-icon fa fa-angle-double-right"></i>
</a>
</li>
<li>
<a th:href="'/UserInfo?pageNum='+${pageInfo.pages}">尾頁</a>
</li>
</ul>
</div>
<div>當前頁號：<span th:text="${pageInfo.pageNum}"></span></div>
<div>每頁條數：<span th:text="${pageInfo.pageSize}"></span></div>
<div>起始行號：<span th:text="${pageInfo.startRow}"></span></div>
<div>終止行號：<span th:text="${pageInfo.endRow}"></span></div>
<div>總結果數：<span th:text="${pageInfo.total}"></span></div>
<div>總頁數：<span th:text="${pageInfo.pages}"></span></div>
<hr />
<div>是否為第一頁：<span th:text="${pageInfo.isFirstPage}"></span></div>
<div>是否為最後一頁：<span th:text="${pageInfo.isLastPage}"></span></div>
<div>是否有前一頁：<span th:text="${pageInfo.hasPreviousPage}"></span></div>
<div>是否有下一頁：<span th:text="${pageInfo.hasNextPage}"></span></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js" integrity="sha512-bLT0Qm9VnAYZDflyKcBaQ2gg0hSYNQrJ8RilYldYQ1FxQYoCLtUjuuRuZo+fjqhx/qtq/1itJ0C2ejDxltZVFg==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
<script src="https://unpkg.com/[email protected]/dist/bootstrap-table.min.js"></script>
</body>
</html>
- 效果
2.1 總結
相比其他分頁外掛而言，pagehelper強大的很多。個人覺得用起來還是挺香的。