自定义MVC系列（三）之MVC框架实现增删改查-阿里云开发者社区

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

http://t.csdn.cn/a0Ib8

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()+")'>&lt;</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()+")'>&gt;</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

自定义MVC系列（三）之MVC框架实现增删改查

前言

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

2.将分页标签相关文件、及相关助手类导入

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】

4.完成通用的增删改方法

5.完成Book实体类及bookDao的编写【模拟】

6.完成BookAction

7.前台代码的编写

运行效果如下

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插件

自定义MVC系列（三）之MVC框架实现增删改查

前言

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

2.将分页标签相关文件、及相关助手类导入

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】

4.完成通用的增删改方法

5.完成Book实体类及bookDao的编写【模拟】

6.完成BookAction

7.前台代码的编写

运行效果如下

热门文章

最新文章

相关课程

相关电子书