自定义mvc的增删改查

短命女 2024-03-17 14:25 15阅读 0赞

## 1.将框架导出打包成jar包 ##

1.![4b3ea8e03ed647b185eb884e69eedd0c.png][]

### 1.2 选中我们的助手包点击export ###

出现![d4bdbfe70b2a4d0fa9d8bdeb959f57e6.png][]

### 1.3在输入框中输入jar点击选择jar file点击next ###

![37e92d34236e40248ba54219db36022b.png][]

### 1.4 点击browse ###

输入文件名mvc点击finsih就得到我们的jar包了

## 2、导入配置文夹 ##

### 2.1中央控制器 ###

<?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>mymvc_crud</display-name>
      <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>

### 2.2增删改配置文件 ###

<?xml version="1.0" encoding="UTF-8"?>
    <config>
    	<action path="/book" type="com.zking.web.BookAction">
    
    
    
    		<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>

### 3、编写后端代码 ###

### 3.1 通用增删改查 ###

package com.zking.util;
     
    import java.lang.reflect.Field;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.util.ArrayList;
    import java.util.List;
     
    import com.zking.util.DBAccess;
    import com.zking.util.PageBean;
     
    /**
     * 所有Dao层的父类
     * 
     * @author 
     *
     * @2023年7月3日 下午10:52:21
     */
    public class BaseDao<T> {
    	/**
    	 * 通用的增删改方法
    	 * 
    	 * @param book
    	 * @throws Exception
    	 */
    	public void executeUpdate(String sql, T t, String[] attrs) throws Exception {
    		Connection con = DBAccess.getConnection();
    		PreparedStatement pst = con.prepareStatement(sql);
    		/*
    		 * 思路： 1.从传进来的t中读取属性值 2.往预定义对象中设置了值
    		 * 
    		 * t->book f->bid
    		 */
    		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));
    		}
    		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
    			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) {
    		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) {
    		return sql + " limit " + pageBean.getStartIndex() + "," + pageBean.getRows();
    	}
    }

### 3. 2book实现增删改查类 ###

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;
     
    /**
     * book工作类
     * @author 
     *
     * @2023年7月3日 下午10:53:52
     */
    public class BookAction extends ActionSupport implements ModelDriver<Book>{
    	private Book book = new Book();
    	private BookDao bookDao = new BookDao();
    	@Override
    	public Book getModel() {
    		return book;
    	}
    	
    	/*
    	 * 增删改最终都要跳回查询界面
    	 * 分析增删改查一共有多少结果集的配置
    	 * 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
    	 */
    	public String add(HttpServletRequest req, HttpServletResponse resp) {
    		try {
    			bookDao.add(book);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "toList";
    	}
    	
    	public String list(HttpServletRequest req, HttpServletResponse resp) {
    		try {
    			PageBean pageBean = new PageBean();
    			pageBean.setRequest(req);
    			List<Book> list = bookDao.list(book,pageBean);
    			req.setAttribute("books", list);
    			req.setAttribute("pageBean", pageBean);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "list";
    	}
    	
    	public String delete(HttpServletRequest req, HttpServletResponse resp) {
    		try {
    			bookDao.delete(book);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "toList";
    	}
    	
    	public String edit(HttpServletRequest req, HttpServletResponse resp) {
    		try {
    			bookDao.edit(book);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "toList";
    	}
    	/**
    	 * 跳转到新增修改页面
    	 * @param req
    	 * @param resp
    	 * @return
    	 */
    	public String toEdit(HttpServletRequest req, HttpServletResponse resp) {
    		try {
    			/*
    			 * 如果是跳转修改页面，那么需要做bid条件的精准查询
    			 */
    			if(book.getBid() != 0) {
    				List<Book> list = bookDao.list(book, null);
    				req.setAttribute("b", list.get(0));
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "toEdit";
    	}
    }

### 3.4.分页助手类 ###

package com.zking.tag;
     
    import com.zking.util.PageBean;
     
    import javax.servlet.jsp.JspException;
    import javax.servlet.jsp.JspWriter;
    import javax.servlet.jsp.tagext.BodyTagSupport;
    import java.io.IOException;
    import java.util.Map;
    import java.util.Set;
     
    /**
     * Page助手类
     * 
     * @author
     *
     */
    public class PageTag extends BodyTagSupport {
    	private static final long serialVersionUID = 1L;
     
    	private PageBean pageBean;
     
    	public PageBean getPageBean() {
    		return pageBean;
    	}
     
    	public void setPageBean(PageBean pageBean) {
    		this.pageBean = pageBean;
    	}
     
    	@Override
    	public int doStartTag() throws JspException {
    		// 获取流
    		JspWriter out = pageContext.getOut();
    		try {
    			out.print(toHTML());
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    		return SKIP_BODY;
    	}
     
    	/**
    	 * JSP自定义页面内容展示
    	 * 
    	 * @return
    	 */
    	private String toHTML() {
    		StringBuilder sb = new StringBuilder();
     
    		// 这里拼接的是一个上一次发送的请求以及携带的参数，唯一改变的就是页码
    		sb.append("<form id='pageBeanForm' action='" + pageBean.getUrl() + "' method='post'>");
    		sb.append("<input type='hidden' name='page'>");
    		// 重要设置拼接操作，将上一次请求参数携带到下一次
    		Map<String, String[]> paMap = pageBean.getParameterMap();
    		if (paMap != null && paMap.size() > 0) {
    			Set<Map.Entry<String, String[]>> entrySet = paMap.entrySet();
    			for (Map.Entry<String, String[]> entry : entrySet) {
    				for (String val : entry.getValue()) {
    					if (!"page".equals(entry.getKey())) {
    						sb.append("<input type='hidden' name='" + entry.getKey() + "' value='" + val + "'>");
    					}
    				}
    			}
    		}
    		sb.append("</form>");
    		
    		/**
    		 * 页码数据配置
    		 */
    		int page = pageBean.getPage(); //当前页码
    		int max = pageBean.getMaxPage();//最大页码
    		int before = page > 4 ? 4 : page - 1;//当前页码前面的页码
    		int after = 10 - 1 - before;//当前页码后面的页码
    		
    		//如果最大页码没有10页，就显示当前页面后面的所有页码 max - page
    		after = page + after > max ? max - page : after;
    		// 初始页码和结束页码值判断 disabled
    		boolean startFlag = page == 1;
    		boolean endFlag = max == page;
     
    		// 拼接分页条
    		sb.append("<ul class='pagination'>");
    		sb.append("<li class='page-item " + (startFlag ? "disabled" : "")
    				+ "'><a class='page-link' href='javascript:gotoPage(1)'>首页</a></li>");
    		sb.append("<li class='page-item " + (startFlag ? "disabled" : "")
    				+ "'><a class='page-link' href='javascript:gotoPage(" + pageBean.getPrevPage() + ")'><</a></li>");
     
    		// 代表了当前页的前4页
    		for (int i = before; i > 0; i--) {
    			sb.append("<li class='page-item'><a class='page-link' href='javascript:gotoPage(" + (page - i) + ")'>"
    					+ (page - i) + "</a></li>");
    		}
     
    		sb.append("<li class='page-item active'><a class='page-link' href='javascript:gotoPage(" + pageBean.getPage()
    				+ ")'>" + pageBean.getPage() + "</a></li>");
     
    		// 代表了当前页的后5页
    		for (int i = 1; i <= after; i++) {
    			sb.append("<li class='page-item'><a class='page-link' href='javascript:gotoPage(" + (page + i) + ")'>"
    					+ (page + i) + "</a></li>");
    		}
     
    		sb.append("<li class='page-item " + (endFlag ? "disabled" : "")
    				+ "'><a class='page-link' href='javascript:gotoPage(" + pageBean.getNextPage() + ")'>></a></li>");
    		sb.append("<li class='page-item " + (endFlag ? "disabled" : "")
    				+ "'><a class='page-link' href='javascript:gotoPage(" + pageBean.getMaxPage() + ")'>尾页</a></li>");
    		sb.append(
    				"<li class='page-item go-input'><b>到第</b><input class='page-link' type='text' id='skipPage' name='' /><b>页</b></li>");
    		sb.append("<li class='page-item go'><a class='page-link' href='javascript:skipPage()'>确定</a></li>");
    		sb.append("<li class='page-item'><b>共" + pageBean.getTotal() + "条</b></li>");
    		sb.append("</ul>");
     
    		// 拼接分页的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) > " + max + ") {");
    		sb.append("alert('请输入1~N的数字');");
    		sb.append("return;");
    		sb.append("}");
    		sb.append("gotoPage(page);");
    		sb.append("}");
    		sb.append("</script>");
     
    		return sb.toString();
    	}
    }

## 4、编写前端代码 ##

### 4.1 数据显示主界面 ###

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>	
    <%@taglib uri="http://jsp.xzs.cn" prefix="w" %>	
    <!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">
    <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>
    <c:if test="${empty books }">
    <jsp:forward page="/BookServlet"></jsp:forward>
    </c:if>
    	<form class="form-inline"
    		action="${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">
    				<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.action?methodName=toEdit">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  var="b" items="${books }">
    			<tr>
    				<td>${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="${pageContext.request.contextPath }/book.action?methodName=delete&bid=${b.bid}">删除</a>
    				</td>
    			</tr>
    			</c:forEach>
    		</tbody>
    	</table>
    	
    	<w:page pageBean="${pageBean }"></w:page>
    </body>
    </html>

## 4.2 默认运行显示所有数据servlet ##

package com.zking.web;
     
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
     
    @WebServlet("/BookServlet")
    public class BookServlet extends HttpServlet {
    	private static final long serialVersionUID = 1L;
           
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doPost(request, response);
    	}
     
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		response.sendRedirect(request.getContextPath()+"/book.action?methodName=list");
    	}
     
    }

### 4.3 新增、修改共用页面 ###

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <%@ taglib uri="http://jsp.xzs.cn" prefix="z"%>	
    <%@ 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">
    <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>书籍新增/修改</title>
    </head>
    <body>
    	<form class="form-inline"
    		action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post">
    		书籍ID：<input type="text" name="bid" value="${b.bid }"><br>
    		书籍名称：<input type="text" name="bname" value="${b.bname }"><br>
    		书籍价格：<input type="text" name="price" value="${b.price }"><br>
    		<input type="submit">
    	</form>
     
     
    </body>
    </html>

[4b3ea8e03ed647b185eb884e69eedd0c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/4c036a520ead473d823408d9228bbd34.png
[d4bdbfe70b2a4d0fa9d8bdeb959f57e6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/c9103efb55904aa4a309c11f7dfb16a3.png
[37e92d34236e40248ba54219db36022b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/2a6566d178ce40d4a8bd067c8d66e3a9.png