前言
前两篇的博客中介绍了自定义mvc框架的原理和框架的实现,现在我们就将已经实现了的框架导成jar架包,实现基础的前端的增删改查。
自定义MVC框架实现增删改查
1.将框架打成jar包,然后导入新工程,并且把框架的依赖jar包导入进去
1. 选中framework包,右键选择export
2. 搜索jar,选择JAR file,点击next
3. 选择你要保存的路径,点击finish,就完成了
4. 创建一个项目,将导出的jar架包和所需要用到的依赖添加到lib文件中
2.将分页标签相关文件、及相关助手类导入
1. 分页标签相关文件
如有需要请查看通用分页的实现
2. 标签助手类
package com.zking.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.zking.util.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.getParamMap(); 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.previousPage()+")'><</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.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.nextPage()+")'>></a></li>"); sb.append(" <li class='page-item "+(pageBean.getPage() == pageBean.maxPage() ? "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.maxPage()+") {"); sb.append(" alert('请输入1~"+pageBean.maxPage()+"的数字');"); sb.append(" return;"); sb.append(" }"); sb.append(" gotoPage(page);"); sb.append(" }"); sb.append("</script>"); return sb.toString(); } }
3. tld文件
<?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>zking 1.1 core library</description> <display-name>zking core</display-name> <tlib-version>1.1</tlib-version> <short-name>zking</short-name> <uri>http://jsp.veryedu.cn</uri> <tag> <name>page</name> <tag-class>com.zking.tag.PageTag</tag-class> <body-content>JSP</body-content> <attribute> <name>pageBean</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
3.框架的配置文件添加、以及web.xml的配置-【开源框架的使用都要从这一步开始】
1. 在src同目录下创建一个Source Folder文件夹,放入mvc.xml配置文件
这里我的mvc文件是已经配置好的,后续就不需要再进行更改
<?xml version="1.0" encoding="UTF-8"?> <config> <!-- 在这里每加一个配置,就相当于actions.put("/goods", new GoodsAction()); 这样就解决了代码灵活性的问题 --> <action path="/book" type="com.zking.web.BookAction"> <!-- 查询:BookList.jsp 返回值:list --> <!-- * 增删改确定:book.action?methodName=list 返回值:toList --> <!-- * 增加修改跳转对应界面:bookEdit.jsp 返回值:toEdit --> <forward name="list" path="/bookList.jsp" redirect="false" /> <forward name="toList" path="/book.action?methodName=list" redirect="true" /> <forward name="toEdit" path="/bookEdit.jsp" redirect="false" /> </action> </config>
2. web.xml的配置
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1"> <display-name>mvc_crud</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>mvc</servlet-name> <servlet-class>com.zking.framework.DispatchServlet</servlet-class> <init-param> <param-name>configurationLocation</param-name> <param-value>/mvc.xml</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>mvc</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping> </web-app>
4.完成通用的增删改方法
package com.zking.util; import java.lang.reflect.Field; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.zking.util.DBAccess; import com.zking.util.PageBean; import com.zking.util.StringUtils; /** * 所有dao层的父类 * @author xissl * * @param <T> */ public class BaseDao<T> { /** * 通用的增删改 * @param sql 增删改的sql语句 * @param t 表对应的实体类 * @param attrs 实体类对应的属性 * @return * @throws Exception */ public int executeUpdate(String sql,T t,String[] attrs) throws Exception { Connection con = DBAccess.getConnection(); PreparedStatement pst = con.prepareStatement(sql); for (int i = 0; i < attrs.length; i++) { Field f = t.getClass().getDeclaredField(attrs[i]); f.setAccessible(true); pst.setObject(i+1, f.get(t)); } return pst.executeUpdate(); } /** * 通用分页查询 * @param sql * @param clz * @return * @throws Exception */ public List<T> executeQuery(String sql,Class<T> clz,PageBean pageBean) throws Exception{ List<T> list = new ArrayList<T>(); Connection con = DBAccess.getConnection();; PreparedStatement pst = null; ResultSet rs = null; /* * 是否需要分页? * 无需分页(项目中的下拉框,查询条件教员下拉框,无须分页) * 必须分页(项目中列表类需求、订单列表、商品列表、学生列表...) */ if(pageBean != null && pageBean.isPagination()) { // 必须分页(列表需求) String countSQL = getCountSQL(sql); pst = con.prepareStatement(countSQL); rs = pst.executeQuery(); if(rs.next()) { pageBean.setTotal(String.valueOf(rs.getObject(1))); } // 挪动到下面,是因为最后才处理返回的结果集 // -- sql=SELECT * FROM t_mvc_book WHERE bname like '%圣墟%' // -- pageSql=sql limit (page-1)*rows,rows 对应某一页的数据 // -- countSql=select count(1) from (sql) t 符合条件的总记录数 String pageSQL = getPageSQL(sql,pageBean);//符合条件的某一页数据 pst = con.prepareStatement(pageSQL); rs = pst.executeQuery(); }else { // 不分页(select需求) pst = con.prepareStatement(sql);//符合条件的所有数据 rs = pst.executeQuery(); } while (rs.next()) { T t = clz.newInstance(); Field[] fields = clz.getDeclaredFields(); for (Field f : fields) { f.setAccessible(true); f.set(t, rs.getObject(f.getName())); } list.add(t); } return list; } /** * 将原生SQL转换成符合条件的总记录数countSQL * @param sql * @return */ private String getCountSQL(String sql) { // -- countSql=select count(1) from (sql) t 符合条件的总记录数 return "select count(1) from ("+sql+") t"; } /** * 将原生SQL转换成pageSQL * @param sql * @param pageBean * @return */ private String getPageSQL(String sql,PageBean pageBean) { // (this.page - 1) * this.rows // pageSql=sql limit (page-1)*rows,rows return sql + " limit "+ pageBean.getStartIndex() +","+pageBean.getRows(); } }
5.完成Book实体类及bookDao的编写【模拟】
1. Book实体类
package com.zking.entity; public class Book { private int bid; private String bname; private float price; public Book() { // TODO Auto-generated constructor stub } public int getBid() { return bid; } public void setBid(int bid) { this.bid = bid; } public String getBname() { return bname; } public void setBname(String bname) { this.bname = bname; } public float getPrice() { return price; } public void setPrice(float price) { this.price = price; } public Book(int bid, String bname, float price) { super(); this.bid = bid; this.bname = bname; this.price = price; } @Override public String toString() { return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]"; } }
2. BookDao的编写
package com.zking.dao; import java.util.List; import com.zking.entity.Book; import com.zking.util.BaseDao; import com.zking.util.PageBean; import com.zking.util.StringUtils; public class BookDao extends BaseDao<Book>{ public List<Book> list(Book book, PageBean pageBean) throws Exception { String sql = "select *from t_mvc_book where 1=1"; String bname = book.getBname(); int bid = book.getBid(); if(StringUtils.isNotBlank(bname)) { sql +=" and bname like '%"+bname+"%'"; } if(bid !=0) { sql +=" and bid ="+bid; } return super.executeQuery(sql, Book.class, pageBean); } public int add(Book book) throws Exception { String sql = "insert into t_mvc_book values(?,?,?)"; return super.executeUpdate(sql, book, new String[] {"bid","bname","price"}); } public int upd(Book book) throws Exception { String sql = "update t_mvc_book set bname=?,price=? where bid=?"; return super.executeUpdate(sql, book, new String[] {"bname","price","bid"}); } public int del(Book book) throws Exception { String sql = "delete from t_mvc_book where bid=?"; return super.executeUpdate(sql, book, new String[] {"bid"}); } }
6.完成BookAction
package com.zking.web; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.zking.dao.BookDao; import com.zking.entity.Book; import com.zking.framework.ActionSupport; import com.zking.framework.ModelDriver; import com.zking.util.PageBean; public class BookAction extends ActionSupport implements ModelDriver<Book> { private Book book = new Book(); private BookDao bookdao = new BookDao(); // 查询 public String list(HttpServletRequest req, HttpServletResponse resp) { PageBean pageBean = new PageBean(); pageBean.setRequest(req); try { List<Book> list = bookdao.list(book, pageBean); req.setAttribute("list", list); req.setAttribute("pageBean", pageBean); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "list"; } // 编辑界面 public String toEdit(HttpServletRequest req, HttpServletResponse resp) { try { if(book.getBid()!=0) { List<Book> list = bookdao.list(book, null); req.setAttribute("b", list.get(0)); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toEdit"; } // 新增 public String add(HttpServletRequest req, HttpServletResponse resp) { try { bookdao.add(book); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } // 删除 public String del(HttpServletRequest req, HttpServletResponse resp) { try { bookdao.del(book); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } // 修改 public String upd(HttpServletRequest req, HttpServletResponse resp) { try { bookdao.upd(book); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } @Override public Book getModel() { // TODO Auto-generated method stub return book; } }
7.前台代码的编写
bookList界面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ taglib prefix="z" uri="http://jsp.veryedu.cn" %> <!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>书籍列表</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="${pageContext.request.contextPath }/book.action?methodName=list" method="post"> <div class="form-group mb-2"> <input type="text" class="form-control-plaintext" name="bname" placeholder="请输入书籍名称"> </div> <button type="submit" class="btn btn-primary mb-2">查询</button> <a class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book.action?methodName=toEdit&&bid=${b.bid }">新增</a> </form> <table class="table table-striped"> <thead> <tr> <th scope="col">书籍ID</th> <th scope="col">书籍名</th> <th scope="col">价格</th> <th scope="col">操作</th> </tr> </thead> <tbody> <c:forEach items="${list }" var="b"> <tr> <td>${b.bid }</td> <td>${b.bname }</td> <td>${b.price }</td> <td> <a href="${pageContext.request.contextPath }/book.action?methodName=toEdit&&bid=${b.bid }">修改</a> <a href="${pageContext.request.contextPath }/book.action?methodName=del&&bid=${b.bid }">删除</a> </td> </tr> </c:forEach> </tbody> </table> <z:page pageBean="${pageBean }"></z:page> </body> </html>
bookEdit界面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!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>书籍的编辑界面【新增,修改通用】</title> </head> <body> <form action="${pageContext.request.contextPath }/book.action?methodName=${empty b?'add':'upd'}" method="post"> 编号<input type="text" name="bid" value="${b.bid }"/><br> 名称<input type="text" name="bname" value="${b.bname }"/><br> 价格<input type="text" name="price" value="${b.price }"/><br> <input type="submit"/> </form> </body> </html>
运行效果如下
自定义MVC框架实现增删改改查