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  • ssm框架整合入门系列——查询-分页显示数据

    ssm框架整合入门系列——查询-分页显示数据(pageHelper的使用)

    查询也就是显示操作，在该项目下具体表现为：

    1. 访问index.jsp页面
    2. index.jsp页面发送出查询员工列表请求
    3. EmployeeController 来接受请求，查出员工数据
    4. 来到list.jsp页面进行展示

    修改index.jsp为：

    <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<jsp:forward page="/emps"></jsp:forward>

    在com.liantao.crud.controller下新建EmployeeController.java

    package com.liantao.crud.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.liantao.crud.bean.Employee;
import com.liantao.crud.service.EmployeeService;

/**
 * 处理员工的crud请求
 * @author liantao.me
 *
 */
@Controller
public class EmployeeController {
	
	
	@Autowired
	EmployeeService employeeService;
	/*
	 * 查询员工数据（分页查询）
	 * @return
	 */
	@RequestMapping("/emps")
	public String getEmps(@RequestParam(value="pn",defaultValue="1")Integer pn,Model model){
		
		//引入PageHelper分页插件
		//查询之前需要调用,,传入页码，以及每页的大小
		PageHelper.startPage(pn,5);
		//startPage后面紧跟的是这个查询就是一个分页查询
		List<Employee> emps = employeeService.getAll();
		//使用pageInfo包装查询后的结果，只需要将Pageinfo交给页面就行了
		//封装了详细的分页信息，包括我们查出来的数据,传入连续显示的数据
		PageInfo page = new PageInfo(emps,5);
		model.addAttribute("pageInfo",page);
		return "list";
	}
	
	
}

    在com.liantao.crud.service下新建EmployeeService.java

    package com.liantao.crud.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.RequestParam;

import com.github.pagehelper.PageHelper;
import com.liantao.crud.bean.Employee;
import com.liantao.crud.dao.EmployeeMapper;

@Service
public class EmployeeService {
	
	@Autowired
	EmployeeMapper employeeMapper;
	
	/**  
	 * 查询所有员工数据（分页查询）
	 * @return
	 */
	public List<Employee> getAll() {
		// TODO Auto-generated method stub
	
		return employeeMapper.selectByExampleWithDept(null);
	}

}

    并引入pageHelper插件，添加dependency:

    <!-- 引入pageHelper分页插件 -->
	<dependency>
	    <groupId>com.github.pagehelper</groupId>
	    <artifactId>pagehelper</artifactId>
	    <version>5.0.0</version>
	</dependency>

    然后再mybatis-config.xml中注册，添加plugins(plugins要添加在typeAliases):

    <plugins>
  		<plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin>
  </plugins>

    pageHelp插件使用文档可参照：地址

    在WEB-INF的views目录下新建list.jsp页面

    <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
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>员工列表</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="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    This is my JSP page. <br>
  </body>
</html>

    单元测试

    在com.liantao.crud.test新建一个测试类MvcTest.java，添加代码：

    package com.liantao.crud.test;

import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import com.github.pagehelper.PageInfo;
import com.liantao.crud.bean.Employee;

/**
 * 使用Spring测试模块提供的测试请求功能，测试curd请求的正确性
 * @author asus
 *
 */
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration(locations={"classpath:applicationContext.xml","file:src/main/webapp/WEB-INF/dispatcherServlet-servlet.xml"})
public class MvcTest {
	//传入SpringMvc的ioc
	@Autowired
	WebApplicationContext context;
	
	//虚拟mvc请求，获取到处理结果
	MockMvc mockMvc;
	
	@Before
	public void initMockMvc(){
		mockMvc = MockMvcBuilders.webAppContextSetup(context).build();
	}
	@Test
	public void testPage() throws Exception{
		//模拟请求拿到返回值
		MvcResult result = mockMvc.perform(MockMvcRequestBuilders.get("/emps").param("pn", "1"))
							.andReturn();
		
		//请求成功以后，请求域中会有pageInfo,我们可以取出pageInfo进行验证
		MockHttpServletRequest request = result.getRequest();
		
		PageInfo pi = (PageInfo)request.getAttribute("pageInfo");
		System.out.println("当前页码："+pi.getPageNum());
		System.out.println("总页码："+pi.getPages());
		System.out.println("总记录数："+pi.getTotal());
		System.out.println("再也没需要连续显示的页码：");
		int[] nums = pi.getNavigatepageNums();
		for(int i:nums){
			System.out.println(" "+i);
		}
		
		//获取员工数据
		List<Employee> list = pi.getList();
		for(Employee employee : list){
			System.out.println("ID:"+employee.getEmpId()+"==>Name"+employee.getEmpName());
		}
		
		
	}
	
	
}

    结果：
    MvcTest.java

    succeed

    用bootstrap编写显示页面

    由于，我们Index.jsp的forward，所以我们要编写的页面应该是list.jsp

    bootstrap文档：地址

    代码如下：

    <%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>员工列表</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="styles.css">
	-->
	<!-- 引入jquery -->
	<script type="text/javascript" src="${path}/ssm-crud/static/js/jquery-1.12.4.js"></script>
	<!-- 引入css、js -->
	<link href="${path}/ssm-crud/static/bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet">
	<script src="${path}/ssm-crud/static/bootstrap-3.3.7-dist/js/bootstrap.min.js"></script>
  </head>
  
  <body>
  	<div class="container">
  		<!-- 标题 -->
  		<div class="row">
  			<div class="col-md-12">
  				<h1>SSM-CRUD</h1>
  			</div>
  		</div>
  		<!-- 按钮 -->
  		<div class="row">
  			<div class="col-md-4 col-md-offset-8">
  				<button class="btn btn-primary">新增</button>
  				<button class="btn btn-danger">删除</button>
  			</div>
  		</div>
  		<!-- 显示表格数据 -->
  		<div class="row">
  			<div class="col-md-12">
  				<table class="table table-hover">
  					<tr>
  						<th>#</th>
  						<th>empName</th>
  						<th>gender</th>
  						<th>email</th>
  						<th>deptName</th>
  						<th>操作</th>
  					</tr>
  					<c:forEach items="${pageInfo.list }" var="emp">
  						<tr>
	  						<th>${emp.empId }</th>
	  						<th>${emp.empName }</th>
	  						<th>${emp.gender=="M"?"男":"女" }</th>
	  						<th>${emp.email }</th>
	  						<th>${emp.department.deptName}</th>
	  						<th>
	  							<button class="btn btn-primary btn-sm">
	  							<span class="glyphicon glyphicon-pencil" aria-hidden="true"></span>
	  							编辑</button>
	  							<button class="btn btn-danger btn-sm">
	  							<span class="glyphicon glyphicon-trash" aria-hidden="true"></span>
	  							删除</button>
	  						</th>
  						</tr>
  					</c:forEach>
  					
  				</table>
  			</div>
  		</div>
  		<!-- 显示分页信息 -->
  		<div class="row">
  			<!-- 分页文字信息 -->
  			<div class="col-md-6">
  				当前${pageInfo.pageNum }页,总${pageInfo.pages }页,总${pageInfo.total }条记录
  			</div>
  			<!-- 分页条信息 -->
  			<div class="col-md-6">
  				<nav aria-label="Page navigation">
				  <ul class="pagination">
				  <li><a href="${path }/ssm-crud/emps?pn=1">首页</a></li>
				  <!-- 判断是否有上一页，以便显示点击按钮 -->
				  <c:if test="${pageInfo.hasPreviousPage }">
				  	<li>	
				      <a href="${path }/ssm-crud/emps?pn=${pageInfo.pageNum-1 }" aria-label="Previous">
				        <span aria-hidden="true">&laquo;</span>
				      </a>
				    </li>
				  </c:if>
				  	<!-- 遍历页码 -->
					<c:forEach items="${pageInfo.navigatepageNums }" var="page_Num">
						<c:if test="${page_Num == pageInfo.pageNum }">
							<li class="active"><a href="#">${page_Num }</a></li>
						</c:if>
						<c:if test="${page_Num != pageInfo.pageNum }">
							<li><a href="${path }/ssm-crud/emps?pn=${page_Num }">${page_Num }</a></li>
						</c:if>
					</c:forEach>	    
				    <!-- 判断是否有下一页 -->
				    <c:if test="${pageInfo.hasNextPage }">
				    <li>
				      <a href="${path }/ssm-crud/emps?pn=${pageInfo.pageNum+1 }" aria-label="Next">
				        <span aria-hidden="true">&raquo;</span>
				      </a>
				    </li>
				    </c:if>
				    
				    <li><a href="${path }/ssm-crud/emps?pn=${pageInfo.pages }">末页</a></li>
				  </ul>
				</nav>
  			</div>
  			
  		</div>
  	</div>
  </body>
</html>

    效果如图：

    员工列表

    在不用ajax技术，我们是这样请求的。下一篇将在这基础上改为发送ajax请求进行员工数据的查询
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  • 原文地址：https://www.cnblogs.com/famine/p/9911862.html
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