Spring+SpringMVC+Mybatis实现增删改查--(二)SSM分页查询页面搭建(通过URI请求)
在前面搭建好的Spring+Spring MVC+Mybatis项目基础环境搭建项目中,进行操作。
查询:
1.访问index.jsp
(http://localhost:8080/ssm_crud/)
2.index.jsp页面转发查询员工列表请求
(<jsp:forward page="/emps"></jsp:forward>)
3.EmployeeController接受请求,通过EmployeeService调用查询全部请求。
(List<Employee> emps=employeeService.getAll();)
4.EmployeeService调用查询员工和部门的方法
(employeeMapper.selectByExampleWithDept(null);)
5.在EmployeeController中对查询过来的数据利用pagehelper分页插件封装到pageinfo中。
//这里写一个测试方法来测试是否能够成功查询分页
6.返回到list.jsp页面进行展示分页查询过来的数据
具体流程:
1.src/main/webapp/index.jsp页面转发URI请求
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <jsp:forward page="/emps"></jsp:forward>
2.src/main/java/com.lcz.crud.service/EmployeeService.java
查询所有员工的方法
package com.lcz.crud.service; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import com.lcz.crud.bean.Employee; import com.lcz.crud.dao.EmployeeMapper; @Service public class EmployeeService { @Autowired EmployeeMapper employeeMapper; /** * 查询所有员工 * @return */ public List<Employee> getAll() { return employeeMapper.selectByExampleWithDept(null); } }
3.分页pagehelper插件加载,地址可见
https://github.com/pagehelper/Mybatis-PageHelper/blob/master/wikis/zh/HowToUse.md
(1)在pom.xml中引入pagehelper包
<!-- 分页查询pagehelper插件 --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper</artifactId> <version>5.0.0</version> </dependency> </dependencies>
(2)mybaits_config.xml配置插件
<plugins> <!-- com.github.pagehelper为PageHelper类所在包名 --> <plugin interceptor="com.github.pagehelper.PageInterceptor"> </plugin> </plugins>
4.src/main/java/com.lcz.crud.controller/EmployController.java
实现分页查询员工方法
package com.lcz.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.lcz.crud.bean.Employee; import com.lcz.crud.service.EmployeeService; /** * 处理员工CRUD请求 * @author LvChaoZhang * */ @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 ) { //这不是一个分页查询 //引入PageHelper分页插件 //在查询之前只需要调用,传入页面以及每页的大小 PageHelper.startPage(pn,5); //startpage后面紧跟的这个查询就是一个分页查询 List<Employee> emps=employeeService.getAll(); //用PageInfo对结果进行包装,只需要pageInfo交给页面,封装了详细的分页信息 //包括有我们查询出来的数据,传入连续显示的页数 PageInfo page = new PageInfo(emps,5); model.addAttribute("pageInfo",page); return "list"; } }
5.在src/main/java/com.lcz.crud.test
书写测试方法,测试看是否能够获得分页查询的数据(当前页码、总页码、总记录数、在页面中需要连续显示的页码)
package com.lcz.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.MockMvcBuilder; 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.lcz.crud.bean.Employee; /** * 使用spring测试模块提供的测试请求功能,测试crud请求的正确性 * @author LvChaoZhang * */ @RunWith(SpringJUnit4ClassRunner.class) @WebAppConfiguration @ContextConfiguration(locations={"classpath:applicationContext.xml","classpath:spring_mvc.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; //每次初始化 @Before public void initMokcMvc() { mockMvc=MockMvcBuilders.webAppContextSetup(context).build(); } /** * 测试查询分页 * @throws Exception */ @Test public void testPage() throws Exception { //模拟请求拿到返回值 MvcResult result = mockMvc.perform(MockMvcRequestBuilders.get("/emps").param("pn", "5")).andReturn(); //请求成功后,请求域中会有pageInfo,取出pageInfo来验证 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("在页面需要连续显示的页码"); int[] nums = pi.getNavigatepageNums(); for(int i:nums) { System.out.print(""+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()); } } }
6.返回到src/webapp/WEB-INF/views/list.jsp页面
通过bootstrap来搭建页面,这里bootstrap界面是通过绝对路径来引入的。
若想查看pageinfo中的变量,可以用快捷键ctrl+shift+t搜索pageinfo,打开pageinfo的实现类,其中有pageinfo实现的方法和变量使用。
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>员工列表</title> <% pageContext.setAttribute("APP_PATH", request.getContextPath()); %> <!-- web路径: 不以/开始的相对路径,找资源,以当前资源的路径为基准,经常容易出问题。 以/开始的相对路径,找资源,以服务器的路径为标准(http://localhost:8080);需要加上项目名 http://localhost:3306/crud --> <script type="text/javascript" src="${APP_PATH }/static/js/jquery-3.3.1.min.js"></script> <link href="${APP_PATH }/static/bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet"> <script src="${APP_PATH }/static/bootstrap-3.3.7-dist/js/bootstrap.min.js"></script> </head> <body> <!-- 搭建显示页面 --> <div class="container"> <!-- 标题 --> <div class="row"> <div class="col-md-12"> <h1 >SSM-CRUD</h1> </div> </div> <!-- 新增、删除按钮 --> <div class="row"> <div class="col-md-4 col-md-offset-8"> <button class="btn btn-primary">新增</button> <button class="btn btn-danger">删除</button> </div> </div> <br> <!-- 显示表格数据 --> <div class="row"> <div class="col-md-12"> <table class="table table-hover"> <tr> <th>#</th> <th>empName</th> <th>gender</th> <th>email</th> <th>deptName</th> <th>操作</th> </tr> <c:forEach items="${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,总共${pageInfo.pages}页,总共${pageInfo.total}记录数 </div> <!-- 分页条信息 --> <div class="col-md-6"> <nav aria-label="Page navigation"> <ul class="pagination"> <li><a href="${APP_PATH}/emps?pn=1">首页</a></li> <c:if test="${pageInfo.hasPreviousPage}"> <li> <a href="${APP_PATH}/emps?pn=${pageInfo.pageNum-1}" aria-label="Previous"> <span aria-hidden="true">«</span> </a> </li> </c:if> <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="${APP_PATH}/emps?pn=${page_Num}">${page_Num}</a></li> </c:if> </c:forEach> <c:if test="${pageInfo.hasNextPage}"> <li> <a href="${APP_PATH}/emps?pn=${pageInfo.pageNum+1}" aria-label="Next"> <span aria-hidden="true">»</span> </a> </li> </c:if> <li><a href="${APP_PATH}/emps?pn=${pageInfo.pages}">末页</a></li> </ul> </nav> </div> </div> </div> </body> </html>