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MyBatis 分页插件的使用



这个分页插件好像是国人开发的,有丶厉害。。。

首先导入包

pom.xml
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<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper -->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>5.1.8</version>
</dependency>

然后在 MyBatis 配置里加载一下分页插件

mybatis-config.xml
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<configuration>
<!--分页插件-->
<plugins>
<plugin interceptor="com.github.pagehelper.PageInterceptor">
<property name="helperDialect" value="mysql"/>
<property name="reasonable" value="true"/>
</plugin>
</plugins>
</configuration>

在调用 dao 方法之前,加一句 PageHelper.startPage();,例如在 service 层中

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@Service
public class UserService {
@Resource
UserMapper userMapper;

public List<User> findAllUsers(int page) {
PageHelper.startPage(page, 2); //第一个参数是当前的页数,第二个参数是每页的个数
List<User> list = userMapper.findAllUsers();
return list;
}
}

它就会自动分页惹。。只查询2个结果出来

在 Cotroller 层返回结果之前,还可以用 new PageInfo(); 获取更详细的分页信息。例如

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@Controller
public class UserController {
@Resource
UserService userService;

@RequestMapping("/userlist")
public String UserList(@RequestParam(defaultValue = "1")int page, Model model) {

List<User> list = userService.findAllUsers(page);
model.addAttribute("list", list);

PageInfo pageInfo = new PageInfo(list);
model.addAttribute("pageInfo", pageInfo);
return "userlist";
}
}

PageInfo() 返回的内容可以在 官方文档 查看,也可以自己打印出来看一下

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//用PageInfo对结果进行包装
PageInfo page = new PageInfo(list);
//测试PageInfo全部属性
//PageInfo包含了非常全面的分页属性
assertEquals(1, page.getPageNum());
assertEquals(10, page.getPageSize());
assertEquals(1, page.getStartRow());
assertEquals(10, page.getEndRow());
assertEquals(183, page.getTotal());
assertEquals(19, page.getPages());
assertEquals(1, page.getFirstPage());
assertEquals(8, page.getLastPage());
assertEquals(true, page.isFirstPage());
assertEquals(false, page.isLastPage());
assertEquals(false, page.isHasPreviousPage());
assertEquals(true, page.isHasNextPage());

在前端页面就可以利用这些信息做分页条了。

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<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
<title></title>
<link href="${pageContext.request.contextPath}/static/css/bootstrap.css" rel="stylesheet" type="text/css"/>
<script type="application/javascript" src="${pageContext.request.contextPath}/static/js/jquery-3.3.1.min.js"></script>
<script type="application/javascript" src="${pageContext.request.contextPath}/static/js/bootstrap.js"></script>
</head>
<body>
<div class="container">
<div class="row">
<h1>用户列表</h1>
</div>

<div class="row">
<table class="table table-hover">
<tr>
<th>uid</th>
<th>username</th>
<th>name</th>
<th>state</th>
<th>operation</th>
</tr>

<c:forEach items="${list}" var="item">

<tr>
<td>${item.uid}</td>
<td>${item.username}</td>
<td>${item.name}</td>
<td>${item.state}</td>
<td>
<%--<a href="" class="btn btn-primary">编辑</a>--%>

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#editUserModal" data-uid="${item.uid}">编辑</button>


<a href="" class="btn btn-danger">删除</a>
</td>
</tr>

</c:forEach>
</table>
</div>

<%--分页--%>
<nav aria-label="...">
<ul class="pagination">

<li <c:if test="${!pageInfo.hasPreviousPage}"> class="disabled"</c:if> >
<a href="?page=${pageInfo.pageNum-1}" aria-label="Previous">
<span aria-hidden="true">&laquo;</span>
</a>
</li>

<c:forEach begin="1" end="${pageInfo.pages}" var="i">

<li <c:if test="${pageInfo.pageNum==i}">class="active"</c:if>>
<a href="?page=${i}">${i}</a>
</li>


</c:forEach>

<li <c:if test="${!pageInfo.hasNextPage}"> class="disabled"</c:if> >
<a href="?page=${pageInfo.pageNum+1}" aria-label="Next">
<span aria-hidden="true">&raquo;</span>
</a>
</li>
</ul>
</nav>


</div>

<%--用户编辑模态框--%>
<div class="modal fade" id="editUserModal" tabindex="-1" role="dialog" aria-labelledby="editUserModalLabel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
<h4 class="modal-title" id="editUserModalLabel">编辑用户信息</h4>
</div>
<div class="modal-body">
<form>
<div class="form-group">
<label for="uid-text" class="control-label">uid:</label>
<input type="text" class="form-control" id="uid-text"/>
</div>
<div class="form-group">
<label for="username-text" class="control-label">username:</label>
<input type="text" class="form-control" id="username-text"/>
</div>
<div class="form-group">
<label for="name-text" class="control-label">name:</label>
<input type="text" class="form-control" id="name-text"/>
</div>
<div class="form-group">
<label for="state-text" class="control-label">state:</label>
<input type="text" class="form-control" id="state-text"/>
</div>
</form>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">关闭</button>
<button type="button" class="btn btn-primary">确认修改</button>
</div>
</div>
</div>
</div>

<script type="application/javascript">

$('#editUserModal').on('show.bs.modal', function (event) {



var button = $(event.relatedTarget) // Button that triggered the modal
var uid = button.data('uid') // Extract info from data-* attributes

console.log("${pageContext.request.contextPath}/getuserinfo?uid="+uid);

$.getJSON(
"${pageContext.request.contextPath}/getuserinfo?uid="+uid,
function(data) {
$.each( data, function( key, val ) {
$("#"+key+"-text").val(val);
});
},
function(){

}
);
})

</script>
</body>
</html>

上面的代码顺便包含了用 bootstrap 的模态框实现用户编辑的功能 (通过 ajax 拉取用户信息并填充到表格上)


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