二.后端实现crud
1.利用mybatis插件生成实体模型和mapper接口和xml文件
在生成后的HBookMapper接口中，需要加上@Repository给Spring进行托管
2.编写切面类和工具类
2.1切面类：
package com.YU.aspect; import com.YU.utils.PageBean; import com.github.pagehelper.PageHelper; import com.github.pagehelper.PageInfo; import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.annotation.Around; import org.aspectj.lang.annotation.Aspect; import org.springframework.stereotype.Component; import java.util.List; /** * @author YU * @create 2023-08-25 17:17 */ @Aspect //代表当前类为切面类 @Component //代表当前类交给Spring进行管理 public class PagerAspect { @Around("execution(* *..*biz.*Pager(..))") public Object invoke(ProceedingJoinPoint args) throws Throwable { PageBean pageBean = null; //获取目标方法的所有参数 Object[] ars = args.getArgs(); for (Object param : ars) { if(param instanceof PageBean){ pageBean = (PageBean)param; break; } } if(pageBean != null && pageBean.isPagination()) PageHelper.startPage(pageBean.getPage(),pageBean.getRows()); Object list = args.proceed(); if(null != pageBean && pageBean.isPagination()){ PageInfo pageInfo = new PageInfo((List) list); pageBean.setTotal((int) pageInfo.getTotal()); } return list; } }
2.2 工具类
package com.YU.utils; import javax.servlet.http.HttpServletRequest; import java.io.Serializable; import java.util.Map; public class PageBean implements Serializable { private static final long serialVersionUID = 2422581023658455731L; //页码 private int page=1; //每页显示记录数 private int rows=10; //总记录数 private int total=0; //是否分页 private boolean isPagination=true; //上一次的请求路径 private String url; //获取所有的请求参数 private Map<String,String[]> map; public PageBean() { super(); } //设置请求参数 public void setRequest(HttpServletRequest req) { String page=req.getParameter("page"); String rows=req.getParameter("rows"); String pagination=req.getParameter("pagination"); this.setPage(page); this.setRows(rows); this.setPagination(pagination); this.url=req.getContextPath()+req.getServletPath(); this.map=req.getParameterMap(); } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public Map<String, String[]> getMap() { return map; } public void setMap(Map<String, String[]> map) { this.map = map; } public int getPage() { return page; } public void setPage(int page) { this.page = page; } public void setPage(String page) { if(null!=page&&!"".equals(page.trim())) this.page = Integer.parseInt(page); } public int getRows() { return rows; } public void setRows(int rows) { this.rows = rows; } public void setRows(String rows) { if(null!=rows&&!"".equals(rows.trim())) this.rows = Integer.parseInt(rows); } public int getTotal() { return total; } public void setTotal(int total) { this.total = total; } public void setTotal(String total) { this.total = Integer.parseInt(total); } public boolean isPagination() { return isPagination; } public void setPagination(boolean isPagination) { this.isPagination = isPagination; } public void setPagination(String isPagination) { if(null!=isPagination&&!"".equals(isPagination.trim())) this.isPagination = Boolean.parseBoolean(isPagination); } /** * 获取分页起始标记位置 * @return */ public int getStartIndex() { //(当前页码-1)*显示记录数 return (this.getPage()-1)*this.rows; } /** * 末页 * @return */ public int getMaxPage() { int totalpage=this.total/this.rows; if(this.total%this.rows!=0) totalpage++; return totalpage; } /** * 下一页 * @return */ public int getNextPage() { int nextPage=this.page+1; if(this.page>=this.getMaxPage()) nextPage=this.getMaxPage(); return nextPage; } /** * 上一页 * @return */ public int getPreivousPage() { int previousPage=this.page-1; if(previousPage<1) previousPage=1; return previousPage; } @Override public String toString() { return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", isPagination=" + isPagination + "]"; } }
3.编写biz层
package com.YU.biz; import com.YU.model.HBook; import com.YU.utils.PageBean; import java.util.List; public interface HBookbiz { int deleteByPrimaryKey(Integer bid); int insert(HBook record); int insertSelective(HBook record); HBook selectByPrimaryKey(Integer bid); int updateByPrimaryKeySelective(HBook record); int updateByPrimaryKey(HBook record); List<HBook> listPager(HBook hBook, PageBean pageBean); }
注：
这个方法为查询返回列表方法，包含分页，因为切面类对其进行切面，所以在命名时，必须以Pager结尾
4.配置mapper.xml
<select id="selectBycon" resultType="com.YU.model.HBook" parameterType="com.YU.model.HBook" > select <include refid="Base_Column_List" /> from t_mvc_book <where> <if test="bname != null"> and bname like concat('%',#{bname},'%') </if> </where> </select>
5.编写相应的接口类（HBookMapper）
List<HBook> selectBycon(HBook hBook);
6.处理controller层发送到biz的请求(配置spring-mvc.xml)
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!--1) 扫描com.YU.web及子子孙孙包下的控制器(扫描范围过大，耗时)--> <context:component-scan base-package="com.YU"/> <!--2) 此标签默认注册DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter --> <mvc:annotation-driven /> <!--3) 创建ViewResolver视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!-- viewClass需要在pom中引入两个包：standard.jar and jstl.jar --> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <!--4) 单独处理图片、样式、js等资源 --> <!-- <mvc:resources location="/css/" mapping="/css/**"/> <mvc:resources location="/js/" mapping="/js/**"/> <mvc:resources location="WEB-INF/images/" mapping="/images/**"/>--> <!--处理controller层发送请求到biz，会经过切面的拦截处理--> <aop:aspectj-autoproxy/> </beans>
7.编写tag助手标签类
package com.YU.tag; import java.io.IOException; import java.util.Map; import java.util.Map.Entry; import java.util.Set; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.BodyTagSupport; import com.YU.utils.PageBean; public class PageTag extends BodyTagSupport{ private PageBean pageBean;// 包含了所有分页相关的元素 public PageBean getPageBean() { return pageBean; } public void setPageBean(PageBean pageBean) { this.pageBean = pageBean; } @Override public int doStartTag() throws JspException { // 没有标签体，要输出内容 JspWriter out = pageContext.getOut(); try { out.print(toHTML()); } catch (IOException e) { e.printStackTrace(); } return super.doStartTag(); } private String toHTML() { StringBuffer sb = new StringBuffer(); // 隐藏的form表单---这个就是上一次请求下次重新发的奥义所在 // 上一次请求的URL sb.append("<form action='"+pageBean.getUrl()+"' id='pageBeanForm' method='post'>"); sb.append(" <input type='hidden' name='page'>"); // 上一次请求的参数 Map<String, String[]> paramMap = pageBean.getMap(); if(paramMap != null && paramMap.size() > 0) { Set<Entry<String, String[]>> entrySet = paramMap.entrySet(); for (Entry<String, String[]> entry : entrySet) { // 参数名 String key = entry.getKey(); // 参数值 for (String value : entry.getValue()) { // 上一次请求的参数，再一次组装成了新的Form表单 // 注意：page参数每次都会提交，我们需要避免 if(!"page".equals(key)) { sb.append(" <input type='hidden' name='"+key+"' value='"+value+"' >"); } } } } sb.append("</form>"); // 分页条 sb.append("<ul class='pagination justify-content-center'>"); sb.append(" <li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'"); sb.append(" href='javascript:gotoPage(1)'>首页</a></li>"); sb.append(" <li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'"); sb.append(" href='javascript:gotoPage("+pageBean.getPreivousPage()+")'><</a></li>");// less than 小于号 // sb.append(" <li class='page-item'><a class='page-link' href='#'>1</a></li>"); // sb.append(" <li class='page-item'><a class='page-link' href='#'>2</a></li>"); sb.append(" <li class='page-item active'><a class='page-link' href='#'>"+pageBean.getPage()+"</a></li>"); sb.append(" <li class='page-item "+(pageBean.getPage() == pageBean.getMaxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.nextPage()+")'>></a></li>"); sb.append(" <li class='page-item "+(pageBean.getPage() == pageBean.getMaxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.maxPage()+")'>尾页</a></li>"); sb.append(" <li class='page-item go-input'><b>到第</b><input class='page-link'"); sb.append(" type='text' id='skipPage' name='' /><b>页</b></li>"); sb.append(" <li class='page-item go'><a class='page-link'"); sb.append(" href='javascript:skipPage()'>确定</a></li>"); sb.append(" <li class='page-item'><b>共"+pageBean.getTotal()+"条</b></li>"); sb.append("</ul>"); // 分页执行的JS代码 sb.append("<script type='text/javascript'>"); sb.append(" function gotoPage(page) {"); sb.append(" document.getElementById('pageBeanForm').page.value = page;"); sb.append(" document.getElementById('pageBeanForm').submit();"); sb.append(" }"); sb.append(" function skipPage() {"); sb.append(" var page = document.getElementById('skipPage').value;"); sb.append(" if (!page || isNaN(page) || parseInt(page) < 1 || parseInt(page) > "+pageBean.getMaxPage()+") {"); sb.append(" alert('请输入1~"+pageBean.getMaxPage()+"的数字');"); sb.append(" return;"); sb.append(" }"); sb.append(" gotoPage(page);"); sb.append(" }"); sb.append("</script>"); return sb.toString(); } }
8.引入tld标签库
<?xml version="1.0" encoding="UTF-8" ?> <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0"> <description>YU 1.1 core library</description> <display-name>YU core</display-name> <tlib-version>1.1</tlib-version> <short-name>YU</short-name> <uri>http://jsp.veryedu.cn</uri> <tag> <name>page</name> <tag-class>com.YU.tag.PageTag</tag-class> <body-content>JSP</body-content> <attribute> <name>pageBean</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
9.编写controller类
package com.YU.web; import com.YU.biz.HBookbiz; import com.YU.model.HBook; import com.YU.utils.PageBean; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import javax.servlet.http.HttpServletRequest; import java.util.List; /** * @author YU * @create 2023-09-07 16:07 */ @Controller @RequestMapping("book") public class HbookController { @Autowired private HBookbiz hBookbiz; //增加 @RequestMapping("/add") public String add(HBook hBook){ hBookbiz.insertSelective(hBook); return "redirect:/book/list"; } //删除 @RequestMapping("/del/{bid}") public String del(@PathVariable("bid")Integer bid){ hBookbiz.deleteByPrimaryKey(bid); return "redirect:/book/list"; } //修改 @RequestMapping("/edit") public String edit(HBook hBook){ hBookbiz.updateByPrimaryKeySelective(hBook); return "redirect:list"; } //查询 @RequestMapping("/list") public String list(HBook hBook, HttpServletRequest request){ // hbook用来接收前台传递后台的参数 PageBean pageBean = new PageBean(); pageBean.setRequest(request); List<HBook> hBooks = hBookbiz.listPager(hBook, pageBean); request.setAttribute("lst",hBooks); request.setAttribute("pageBean",pageBean); return "book/list"; } //数据回显 @RequestMapping("/preSave") public String preSave(HBook hBook, Model model){ if(hBook !=null && hBook.getBid()!=null && hBook.getBid()!=0){ HBook b = hBookbiz.selectByPrimaryKey(hBook.getBid()); model.addAttribute("b",b); } return "book/edit"; } }
10.编写前端页面
1.主页面(展示数据进行操作)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css" rel="stylesheet"> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script> <title>博客列表</title> <style type="text/css"> .page-item input { padding: 0; width: 40px; height: 100%; text-align: center; margin: 0 6px; } .page-item input, .page-item b { line-height: 38px; float: left; font-weight: 400; } .page-item.go-input { margin: 0 10px; } </style> </head> <body> <form class="form-inline" action="${pageContext.request.contextPath }/book/list" method="get"> <div class="form-group mb-2"> <input type="text" class="form-control-plaintext" name="cname" placeholder="请输入班级名称"> <!-- <input name="rows" value="20" type="hidden"> --> <!-- 不想分页 --> <%-- <input name="pagination" value="false" type="hidden">--%> </div> <button type="submit" class="btn btn-primary mb-2">查询</button> <a class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book/preSave">新增</a> </form> <table class="table table-striped"> <thead> <tr> <th scope="col">书籍ID</th> <th scope="col">书籍名称</th> <th scope="col">书籍价格</th> <%-- <th scope="col">班级图片</th>--%> <th scope="col">操作</th> </tr> </thead> <tbody> <c:forEach var="b" items="${lst }"> <tr> <td>${b.bid }</td> <td>${b.bname }</td> <td>${b.price }</td> <td> <a href="${pageContext.request.contextPath }/book/preSave?bid=${b.bid}">修改</a> <a href="${pageContext.request.contextPath }/book/del/${b.bid}">删除</a> </td> </tr> </c:forEach> </tbody> </table> <!-- 这一行代码就相当于前面分页需求前端的几十行了 --> <z:page pageBean="${pageBean }"></z:page> ${pageBean } </body> </html>
2.增加修改界面(操作数据)
<body> <form action="${pageContext.request.contextPath }/${empty b ? 'book/add' : 'book/edit'}" method="post"> cid:<input type="text" name="bid" value="${b.bid }"><br> bname:<input type="text" name="bname" value="${b.bname }"><br> price:<input type="text" name="price" value="${b.price }"><br> <input type="submit"> </form> </body>
3.测试结果
感谢各位大大的收看，各位的支持和三连是博主更新的动力，感谢谢谢谢！！！！
