• 自定义MVC增删改查

    目录

    一、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

    二、将分页标签相关文件、及相关助手类导入

    三、完成Book实体类及bookdao的编写

    四、完成通用的增删改方法

    五、完成BookAction

    六.xml的配置 

    七、前台代码的编写 

    一、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

    将Framework包导成jar包

            ​

     搜索框搜索jar

    选中JAR File，然后点击下一步

     

     红色区域选择路径，点击finish

     

     直接点击Ok就可以了

     将相关依赖的jar包导入

    二、将分页标签相关文件、及相关助手类导入

    将博主之前所写的通用分页文章中util工具包和tag标签导入

     

     

    三、完成Book实体类及bookdao的编写

    1. package com.zwc.entity;
    2.  
    3. public class Book {
    4. 	private int bid;
    5. 	private String bname;
    6. 	private float price;
    7. 	public int getBid() {
    8. 		return bid;
    9. 	}
    10. 	public void setBid(int bid) {
    11. 		this.bid = bid;
    12. 	}
    13. 	public String getBname() {
    14. 		return bname;
    15. 	}
    16. 	public void setBname(String bname) {
    17. 		this.bname = bname;
    18. 	}
    19. 	public float getPrice() {
    20. 		return price;
    21. 	}
    22. 	public void setPrice(float price) {
    23. 		this.price = price;
    24. 	}
    25. 	
    26. 	public Book() {
    27. 		// TODO Auto-generated constructor stub
    28. 	}
    29. 	public Book(int bid, String bname, float price) {
    30. 		super();
    31. 		this.bid = bid;
    32. 		this.bname = bname;
    33. 		this.price = price;
    34. 	}
    35. 	@Override
    36. 	public String toString() {
    37. 		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
    38. 	}
    39. 	
    40. 	
    41. }

    Bookdao(基础的增删改)

    1. package com.zwc.dao;
    2.  
    3. import java.sql.Connection;
    4. import java.sql.PreparedStatement;
    5. import java.sql.SQLException;
    6. import java.util.ArrayList;
    7. import java.util.List;
    8.  
    9. import com.zwc.entity.Book;
    10. import com.zwc.util.BaseDao;
    11. import com.zwc.util.DBAccess;
    12. import com.zwc.util.PageBean;
    13. import com.zwc.util.StringUtils;
    14.  
    15. public class BookDao extends BaseDao<Book>{
    16. //	查询
    17. 	public List<Book> list(Book book,PageBean pageBean) throws Exception{
    18. 		String sql = "select * from t_mvc_book where 1=1 ";
    19. 		
    20. 		String bname = book.getBname();
    21. 		if(StringUtils.isNotBlank(bname)) {
    22. 			sql +=" and bname like '%"+bname+"%'";
    23. 		}
    24. 		int bid = book.getBid();
    25. //		前台jsp传递到后台，只要传了就有值，没传就是默认值，默认值就是0
    26. 		if(bid!=0) {
    27. 			sql +=" and bid ="+bid;
    28. 		}
    29. 		return super.executeQuery(sql, pageBean, rs ->{
    30. 			List<Book> list = new ArrayList<>();
    31. 			try {
    32. 				while(rs.next()) {
    33. 					list.add(new Book(rs.getInt("bid"), rs.getString("bname"),rs.getFloat("price")));
    34. 				}
    35. 			} catch (SQLException e) {
    36. 				e.printStackTrace();
    37. 			}
    38. 			return list;
    39. 		});
    40. 	}
    41. 	
    42. 	
    43. //	增
    44. 	public int add(Book book) throws Exception {
    45. 		Connection con = DBAccess.getConnection();
    46. 		String sql="insert into t_mvc_book values(?,?,?)";
    47. 		PreparedStatement pst = con.prepareStatement(sql);
    48. 		pst.setObject(1, book.getBid());
    49. 		pst.setObject(2, book.getBname());
    50. 		pst.setObject(3, book.getPrice());
    51. 		return pst.executeUpdate();
    52. 	}
    53. 	
    54. //	删
    55. 	public int del(Book book) throws Exception {
    56. 		Connection con = DBAccess.getConnection();
    57. 		String sql="delete from t_mvc_book where bid = ?";
    58. 		PreparedStatement pst = con.prepareStatement(sql);
    59. 		pst.setObject(1, book.getBid());
    60. 		return pst.executeUpdate();
    61. 	}
    62.  
    63. //	改
    64. 	public int edit(Book book) throws Exception {
    65. 		Connection con = DBAccess.getConnection();
    66. 		String sql="update t_mvc_book set bname=?,price=? where bid = ?";
    67. 		PreparedStatement pst = con.prepareStatement(sql);
    68. 		pst.setObject(1, book.getBname());
    69. 		pst.setObject(2, book.getPrice());
    70. 		pst.setObject(3, book.getBid());
    71. 		return pst.executeUpdate();
    72. 	}
    73. 	
    74. 	
    75. }
    76.

    四、完成通用的增删改方法

    大家可以发现上面基础的增删改代码都有一些相同代码


            Connection con = DBAccess.getConnection();
            PreparedStatement pst = con.prepareStatement(sql);
            pst.setObject(1, book.getBname());
            pst.setObject(2, book.getPrice());
            pst.setObject(3, book.getBid());
     

    所以我们要把它写成一个通用增删改

    因为我们bookdao继承了basedao

    basedao：

    1. package com.zwc.util;
    2.  
    3. import java.lang.reflect.Field;
    4. import java.sql.Connection;
    5. import java.sql.PreparedStatement;
    6. import java.sql.ResultSet;
    7. import java.util.ArrayList;
    8. import java.util.List;
    9.  
    10. import com.zwc.entity.Book;
    11.  
    12.  
    13. /**
    14.  * T代表实体类，可以是book/User/Goods...
    15.  * @author Administrator
    16.  *
    17.  * @param <T>
    18.  */
    19. public class BaseDao<T> {
    20. //	public  List<T> executeQuery(String sql,PageBean pageBean,CallBack<T> callBack) throws Exception{
    21. 		sql="select * from t_mvc_book WHERE bname like '%圣墟%'";
    22. 		从上面得到select COUNT(1) as n from (select * from t_mvc_book WHERE bname like '%圣墟%') t;
    23. 		目的是为了得到总记录数->得到总页数
    24. //		select * from t_mvc_book WHERE bname like '%圣墟%' LIMIT 10,10;
    25. //
    26. //		/**
    27. //		 * 1、拿到数据库连接
    28. //		 * 2、拿到preparestatement
    29. //		 * 3、执行sql语句
    30. //		 */
    31. //		Connection con = DBAccess.getConnection();//重复代码1
    32. //		PreparedStatement pst = con.prepareStatement(sql);//重复代码2
    33. //		ResultSet rs = pst.executeQuery();//重复代码3
    34. 		while(rs.next()) {
    35. 			list.add(new Book(rs.getInt("bid"), rs.getString("bname"),rs.getFloat("price") ));
    36. 		}
    37. 		查询不同表，必然要处理不同的结果集
    38. 		接口是调用方来实现
    39. //		return callBack.foreach(rs);
    40. //	}
    41. 	
    42. 	
    43. 	public  List<T> executeQuery(String sql,PageBean pageBean,CallBack<T> callBack) throws Exception{
    44.  
    45. 		/**
    46. 		 * 1、拿到数据库连接
    47. 		 * 2、拿到preparestatement
    48. 		 * 3、执行sql语句
    49. 		 */
    50. 		Connection con = null;//重复代码1
    51. 		PreparedStatement pst = null;//重复代码2
    52. 		ResultSet rs = null;//重复代码3
    53. 		if(pageBean !=null && pageBean.isPagination()) {
    54. 			String countSQL = getCountSQL(sql);
    55. 			con = DBAccess.getConnection();
    56. 			pst = con.prepareStatement(countSQL);
    57. 			rs = pst.executeQuery();
    58. 			if(rs.next()) {
    59. //				当前实体类就包含了记录数
    60. 				pageBean.setTotal(rs.getString("n"));
    61. 			}
    62. 			String pageSQL = getPageSQL(sql,pageBean);
    63. 			con = DBAccess.getConnection();
    64. 			pst = con.prepareStatement(pageSQL);
    65. 			rs = pst.executeQuery();
    66. 		}
    67. 		else {
    68. 			con = DBAccess.getConnection();
    69. 			pst = con.prepareStatement(sql);
    70. 			rs = pst.executeQuery();
    71. 		}
    72. 		
    73. 		 
    74. //		查询不同表，必然要处理不同的结果集
    75. //		接口是调用方来实现
    76. 		return callBack.foreach(rs);
    77. 	}
    78.  
    79. 		/**
    80. 		 * 拼装第n页的数据的sql
    81. 		 * @param sql
    82. 		 * @param pageBean
    83. 		 * @return
    84. 		 */
    85. 		private String getPageSQL(String sql, PageBean pageBean) {
    86. 		return sql + " limit "+pageBean.getStartIndex()+","+pageBean.getRows();
    87. }
    88.  
    89. 		/**
    90. 		 * 拼装符合条件总记录数的sql
    91. 		 * @param sql
    92. 		 * @return
    93. 		 */
    94. 		private String getCountSQL(String sql) {
    95. //		sql="select * from t_mvc_book WHERE bname like '%圣墟%'";
    96. //		从上面得到select COUNT(1) as n from (select * from t_mvc_book WHERE bname like '%圣墟%') t;
    97. 			return "select count(1) as n from ("+sql+") t";
    98. 		}
    99. 		
    100. 		
    101. 		public int executeUpdate(String sql,T t,String[] attrs) throws Exception {
    102. 			Connection con = DBAccess.getConnection();
    103. 			PreparedStatement pst = con.prepareStatement(sql);
    104. //			将t的某一个属性对应的值加到pst对象中
    105. 			for (int i = 0; i < attrs.length; i++) {
    106. 				Field f = t.getClass().getDeclaredField(attrs[i]);
    107. 				f.setAccessible(true);
    108. 				pst.setObject(i+1, f.get(t));
    109. 			}
    110. 			return pst.executeUpdate();
    111. 		}
    112. }

    Bookdao :

    1. package com.zwc.dao;
    2.  
    3. import java.sql.Connection;
    4. import java.sql.PreparedStatement;
    5. import java.sql.SQLException;
    6. import java.util.ArrayList;
    7. import java.util.List;
    8.  
    9. import com.zwc.entity.Book;
    10. import com.zwc.util.BaseDao;
    11. import com.zwc.util.DBAccess;
    12. import com.zwc.util.PageBean;
    13. import com.zwc.util.StringUtils;
    14.  
    15. public class BookDao extends BaseDao<Book>{
    16. //	查询
    17. 	public List<Book> list(Book book,PageBean pageBean) throws Exception{
    18. 		String sql = "select * from t_mvc_book where 1=1 ";
    19. 		
    20. 		String bname = book.getBname();
    21. 		if(StringUtils.isNotBlank(bname)) {
    22. 			sql +=" and bname like '%"+bname+"%'";
    23. 		}
    24. 		int bid = book.getBid();
    25. //		前台jsp传递到后台，只要传了就有值，没传就是默认值，默认值就是0
    26. 		if(bid!=0) {
    27. 			sql +=" and bid ="+bid;
    28. 		}
    29. 		return super.executeQuery(sql, pageBean, rs ->{
    30. 			List<Book> list = new ArrayList<>();
    31. 			try {
    32. 				while(rs.next()) {
    33. 					list.add(new Book(rs.getInt("bid"), rs.getString("bname"),rs.getFloat("price")));
    34. 				}
    35. 			} catch (SQLException e) {
    36. 				e.printStackTrace();
    37. 			}
    38. 			return list;
    39. 		});
    40. 	}
    41. 	
    42. 	
    43. //	增
    44.  
    45. 	public int add(Book book) throws Exception {
    46. 		String sql="insert into t_mvc_book values(?,?,?)";
    47. //      super调用basedao最后一个方法
    48. 		return super.executeUpdate(sql, book, new String[] {"bid","bname","price"});
    49. 	}
    50.  
    51. //	删
    52.  
    53. 	public int del(Book book) throws Exception {
    54. 		String sql="delete from t_mvc_book where bid = ?";
    55. 		return super.executeUpdate(sql, book,new String[] {"bid"});
    56. 	}
    57. 	
    58. //	改
    59.  
    60. 	public int edit(Book book) throws Exception {
    61. 		String sql="update t_mvc_book set bname=?,price=? where bid = ?";
    62. 		return super.executeUpdate(sql, book, new String[] {"bname","price","bid"});
    63. 	}
    64. 	
    65. 	
    66. 	
    67. }

    五、完成BookAction

            BookAction:

    1. package com.zwc.web;
    2.  
    3. import java.util.List;
    4.  
    5. import javax.servlet.http.HttpServletRequest;
    6. import javax.servlet.http.HttpServletResponse;
    7.  
    8. import com.zwc.dao.BookDao;
    9. import com.zwc.entity.Book;
    10. import com.zwc.framework.ActionSupport;
    11. import com.zwc.framework.ModelDrivetr;
    12. import com.zwc.util.PageBean;
    13.  
    14. public class BookAction extends ActionSupport implements ModelDrivetr<Book>{
    15.  
    16. 	private Book b = new Book();
    17. 	private BookDao book = new BookDao();
    18. 	
    19. 	@Override
    20. 	public Book getModel() {
    21. 		return b;
    22. 	}
    23.  
    24. //	增
    25. 	public String add(HttpServletRequest req, HttpServletResponse resp) {
    26. 		try {
    27. 			book.add(b);
    28. 		} catch (Exception e) {
    29. 			e.printStackTrace();
    30. 		}
    31. //		tolist代表跳到查询方法
    32. 		return "toList";
    33. 	}
    34. 	
    35. //	删
    36. 	public String del(HttpServletRequest req, HttpServletResponse resp) {
    37. 		try {
    38. 			book.del(b);
    39. 		} catch (Exception e) {
    40. 			e.printStackTrace();
    41. 		}
    42. //		tolist代表跳到查询方法
    43. 		return "toList";
    44. 	}
    45. 	
    46. //	修改
    47. 	public String edit(HttpServletRequest req, HttpServletResponse resp) {
    48. 		try {
    49. 			book.edit(b);
    50. 		} catch (Exception e) {
    51. 			e.printStackTrace();
    52. 		}
    53. //		tolist代表跳到查询方法
    54. 		return "toList";
    55. 	}
    56. 	
    57. //	查询
    58. 	public String list(HttpServletRequest req, HttpServletResponse resp) {
    59. 		try {
    60. 			PageBean pageBean  = new PageBean();
    61. 			pageBean.setRequest(req);
    62. 			List<Book> list = book.list(b, pageBean);
    63. 			req.setAttribute("list", list);
    64. 			req.setAttribute("pageBean", pageBean);
    65. 		} catch (Exception e) {
    66. 			e.printStackTrace();
    67. 		}
    68. //		执行查询展示
    69. 		return "list";
    70. 	}
    71. 	
    72. 	
    73. //	跳转到新增/修改界面
    74. 	public String preEdit(HttpServletRequest req, HttpServletResponse resp) {
    75. 		try {
    76. 			int bid = b.getBid();
    77. 			if(bid!=0) {
    78. //				传递bid到后台，有且只能查出一条数据，那也就意味着list集合中只有一条
    79. 				List<Book> list = book.list(b, null);
    80. 				req.setAttribute("b", list.get(0));
    81. 			}
    82. 		} catch (Exception e) {
    83. 			e.printStackTrace();
    84. 		}
    85. //		tolist代表跳到编辑方法
    86. 		return "toEdit";
    87. 	}
    88. 	
    89.  
    90. 	
    91. 	
    92. }

    六.xml的配置 

    web.xml

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <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">
    3.   <display-name>T280_recf</display-name>
    4.  <servlet>
    5.  	<servlet-name>mvc</servlet-name>
    6.  	<servlet-class>com.zwc.framework.DispatcherServlet</servlet-class>
    7.  	<init-param>
    8.  		<param-name>configLocation</param-name>
    9.  		<param-value>/zwc.xml</param-value>
    10.  	</init-param>
    11.  </servlet>
    12.  <servlet-mapping>
    13.  	<servlet-name>mvc</servlet-name>
    14.  	<url-pattern>*.action</url-pattern>
    15.  </servlet-mapping>
    16. </web-app>

    XML配置 

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. 	
    3. <config>
    4. 	
    5. 	<action path="/book" type="com.zwc.web.BookAction">
    6. 		<forward name="list" path="/bookList.jsp" redirect="false" />
    7. 		<forward name="toEdit" path="/bookEdit.jsp" redirect="false" />
    8. 		<forward name="toList" path="/book.action?methodName=list" redirect="true" />
    9. 	</action>
    10.  
    11. </config>

    七、前台代码的编写 

    主界面

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2. 	pageEncoding="UTF-8"%>
    3. 	<%@ taglib prefix="z" uri="http://jsp.zwcedu.cn" %>
    4. 	<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    5. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    6. <html>
    7. <head>
    8. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    9. <link
    10. 	href='https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css'
    11. 	rel='stylesheet'>
    12. <script
    13. 	src='https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js'></script>
    14. <title>书籍列表</title>
    15. <style type="text/css">
    16. .page-item input {
    17. 	padding: 0;
    18. 	width: 40px;
    19. 	height: 100%;
    20. 	text-align: center;
    21. 	margin: 0 6px; 
    22. }
    23.  
    24. .page-item input, .page-item b {
    25. 	line-height: 38px;
    26. 	float: left;
    27. 	font-weight: 400;
    28. }
    29.  
    30. .page-item.go-input {
    31. 	margin: 0 10px;
    32. }
    33. </style>
    34. </head>
    35. <body>
    36. 	 <form class="form-inline"
    37. 		action="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
    38. 		<div class="form-group mb-2">
    39. 			<input type="text" class="form-control-plaintext" name="bname"
    40. 				placeholder="请输入书籍名称">
    41. 		</div>
    42. 		<button type="submit" class="btn btn-primary mb-2">查询</button>
    43. 	</form>
    44.  
    45. 	<table class="table table-striped ">
    46. 		<thead>
    47. 			<tr>
    48. 				<th scope="col">书籍ID</th>
    49. 				<th scope="col">书籍名</th>
    50. 				<th scope="col">价格</th>
    51. 				<th scope="col">操作</th>
    52. 			</tr>
    53. 		</thead>
    54. 		<tbody>
    55. 		<c:forEach items="${list}" var="b">
    56. 			<tr>
    57. 				<td>${b.bid}</td>
    58. 				<td>${b.bname}</td>
    59. 				<td>${b.price}</td>
    60. 				<td>
    61. 					<a href="${pageContext.request.contextPath }/book.action?methodName=preEdit&bid=${b.bid}">编辑</a>
    62. 					<a href="${pageContext.request.contextPath }/book.action?methodName=del&bid=${b.bid}">删除</a>
    63. 					<a href="${pageContext.request.contextPath }/book.action?methodName=preEdit">新增</a>
    64. 				</td>
    65. 			</tr>
    66. 		</c:forEach>
    67.  
    68. 		</tbody>
    69. 	</table> 
    70. 	
    71. 	<z:page pageBean="${pageBean }"></z:page>
    72.  
    73. </body>
    74. </html>

    编辑界面

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2.     pageEncoding="UTF-8"%>
    3. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    4. <html>
    5. <head>
    6. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    7. <title>Insert title here</title>
    8. </head>
    9. <body>
    10. <center>
    11. 	<form action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post">
    12. 			编号：<input type="text" name="bid" value="${b.bid }"><br>
    13. 			名字：<input type="text" name="bname" value="${b.bname }"><br>
    14. 			价格：<input type="text" name="price" value="${b.price}">
    15. 			<input type="submit" value="提交">
    16. 	</form>
    17. </center>
    18. </body>
    19. </html>

    主界面效果图：

     

    点击编辑进入编辑界面，点击提交

     

     在主界面可以看到已经改了

    点击增加到增加页面点击提交

     

    主界面展示

     

     点击删除，编号为28的数据

     


     主界面没有编号为28的数据了 

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  • 原文地址：https://blog.csdn.net/qq_65345936/article/details/125517196