• 自定义mvc增删改查

    目录

    一，步骤如下：

    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

    打成jar包的步骤

    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

    4.完成Book实体类一bookDao的编写

    5.完成通用的增删改方法

    6.完成BookAction

    7.完成mvc.xml的配置

    8.完成前台代码的编写

    一，步骤如下：

    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

    打成jar包的步骤

     选择file文件后点击下一步

     

     命名完后点击下一步

     

    jar包打出来后将其导入项目即可

    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

    4.完成Book实体类一bookDao的编写

    《代码演示book》

    1. package com.dengxiyan.entity;
    2.  
    3. public class Book {
    4.  
    5. 	private int bid;
    6. 	private String bname;
    7. 	private float price;
    8.  
    9.  
    10. 	public int getBid() {
    11. 		return bid;
    12. 	}
    13.  
    14. 	public void setBid(int bid) {
    15. 		this.bid = bid;
    16. 	}
    17.  
    18. 	public String getBname() {
    19. 		return bname;
    20. 	}
    21.  
    22. 	public void setBname(String bname) {
    23. 		this.bname = bname;
    24. 	}
    25.  
    26. 	public float getPrice() {
    27. 		return price;
    28. 	}
    29.  
    30. 	public void setPrice(float price) {
    31. 		this.price = price;
    32. 	}
    33.  
    34. 	
    35. 	public Book() {
    36. 		// TODO Auto-generated constructor stub
    37. 	}
    38.  
    39. 	public Book(int bid, String bname, float price) {
    40. 		super();
    41. 		this.bid = bid;
    42. 		this.bname = bname;
    43. 		this.price = price;
    44. 	}
    45. 	
    46. 	@Override
    47. 	public String toString() {
    48. 		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
    49. 	}
    50. 	
    51. 	
    52. }

     《代码演示bookDao》
    以下方法既节省代码，更是便捷了程序人员

    1. package com.dengxiyan.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.dengxiyan.entity.Book;
    10. import com.dengxiyan.util.BaseDao;
    11. import com.dengxiyan.util.DBAccess;
    12. import com.dengxiyan.util.PageBean;
    13. import com.dengxiyan.util.StringUtils;
    14.  
    15. public class BookDao extends BaseDao<Book>{
    16.  
    17. 	//查询
    18. 	public List<Book> list(Book book,PageBean pageBean) throws Exception{
    19. 	 String sql = "select * from tb_book where 1=1 ";
    20. 	 String bname = book.getBname();
    21. 	 if(StringUtils.isNotBlank(bname)) {
    22. 		 sql+= " and bname like '%"+bname+"%'";
    23. 	 }
    24. 	 int bid = book.getBid();
    25. 	 //前台传递到后台，只要传了就有值,没传就是默认值，默认值为0
    26. 	 if(bid!=0) {
    27. 		 sql+= " and bid = "+bid;
    28. 	 }
    29. 		return super.executeQuery(sql, pageBean, rs ->{
    30. 			List<Book> ls = new ArrayList<Book>();
    31. 			try {
    32. 				while(rs.next()) {
    33. 					ls.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
    34. 				}
    35. 			} catch (SQLException e) {
    36. 				e.printStackTrace();
    37. 			}
    38. 			return ls;
    39. 		});
    40. 	}
    41. 	
    42. 	//增加
    43. 	/*public int add(Book b) throws Exception {
    44. 		Connection con = DBAccess.getConnection();
    45. 		String sql = "insert into tb_book values(?,?,?)";
    46. 		PreparedStatement ps = con.prepareStatement(sql);
    47. 		ps.setObject(1, b.getBid());
    48. 		ps.setObject(2, b.getBname());
    49. 		ps.setObject(3, b.getPrice());
    50. 		return ps.executeUpdate();
    51. 	}*/
    52. 	
    53. 	public int add(Book b) throws Exception {
    54. 		String sql = "insert into tb_book values(?,?,?)";
    55. 		return super.executeUpdate(sql, b, new String[] {"bid","bname","price"});
    56. 	}
    57. 	
    58. 	
    59. 	//删除
    60. 	/*public int del(Book b) throws Exception {
    61. 		Connection con = DBAccess.getConnection();
    62. 		String sql = "delete from tb_book where bid=?";
    63. 		PreparedStatement ps = con.prepareStatement(sql);
    64. 		ps.setObject(1, b.getBid());
    65. 		return ps.executeUpdate();
    66. 	}*/
    67. 	
    68. 	public int del(Book b) throws Exception {
    69. 		String sql = "delete from tb_book where bid=?";
    70. 		return super.executeUpdate(sql, b, new String[] {"bid"});
    71. 	}
    72. 	
    73. 	
    74. 	//修改
    75. 	/*public int update(Book b) throws Exception {
    76. 		Connection con = DBAccess.getConnection();
    77. 		String sql = "update tb_book set bname=?,price=? where bid=?";
    78. 		PreparedStatement ps = con.prepareStatement(sql);
    79. 		ps.setObject(1, b.getBname());
    80. 		ps.setObject(2, b.getPrice());
    81. 		ps.setObject(3, b.getBid());
    82. 		return ps.executeUpdate();
    83. 	}*/
    84. 	
    85. 	
    86. 	public int update(Book b) throws Exception {
    87. 		String sql = "update tb_book set bname=?,price=? where bid=?";
    88. 		return super.executeUpdate(sql, b, new String[] {"bname","price","bid"});
    89. 	}
    90. 	
    91. 	
    92. 	
    93. 	
    94. }

    5.完成通用的增删改方法

    《代码演示》

    在bookDao里面继承了改类，并实现了以下方法

    1. //将以下代码不一样的提出来作为参数放到方法里，以及对象不能是定死的，所以将它换为泛型
    2. 		public int executeUpdate(String sql,T t,String [] attrs) throws Exception {
    3. 			Connection con = DBAccess.getConnection();
    4. 			PreparedStatement ps = con.prepareStatement(sql);
    5. 			//将 t 的某一个属性对应的值加到ps对象中
    6. 			for (int i = 0; i < attrs.length; i++) {
    7. 				Field f = t.getClass().getDeclaredField(attrs[i]);
    8. 				f.setAccessible(true);
    9. 				ps.setObject(i+1, f.get(t));
    10. 			}
    11. 			return ps.executeUpdate();
    12. 		}

    6.完成BookAction

    在book子控制器里调用方法

    《代码演示》

    方法里的返回值为xml配置文件里的name值

    1. package com.dengxiyan.servlet;
    2.  
    3. import java.util.List;
    4.  
    5. import javax.servlet.http.HttpServletRequest;
    6. import javax.servlet.http.HttpServletResponse;
    7.  
    8. import com.dengxiyan.dao.BookDao;
    9. import com.dengxiyan.entity.Book;
    10. import com.dengxiyan.framework.ActionSupport;
    11. import com.dengxiyan.framework.ModelDriven;
    12. import com.dengxiyan.util.PageBean;
    13.  
    14. public class BookAction extends ActionSupport implements ModelDriven<Book> {
    15.  
    16. 	private Book book = new Book();
    17. 	private BookDao bookDao = new BookDao();
    18. 	
    19. 	
    20. 	@Override
    21. 	public Book getModel() {
    22. 		// TODO Auto-generated method stub
    23. 		return book;
    24. 	}
    25. 	
    26.  
    27. 	//增加
    28. 	public String add(HttpServletRequest req, HttpServletResponse resp) {
    29. 		try {
    30. 			bookDao.add(book);
    31. 		} catch (Exception e) {
    32. 			// TODO Auto-generated catch block
    33. 			e.printStackTrace();
    34. 		}
    35. 		//表示跳到查询界面
    36. 		return "toList";
    37. 	}
    38. 	
    39. 	
    40. 	//删除
    41. 	public String del(HttpServletRequest req, HttpServletResponse resp) {
    42. 		try {
    43. 			bookDao.del(book);
    44. 		} catch (Exception e) {
    45. 			// TODO Auto-generated catch block
    46. 			e.printStackTrace();
    47. 		}
    48. 		//表示跳到查询界面
    49. 		return "toList";
    50. 	}
    51. 	
    52. 	
    53. 	//修改
    54. 	public String update(HttpServletRequest req, HttpServletResponse resp) {
    55. 		try {
    56. 			bookDao.update(book);
    57. 		} catch (Exception e) {
    58. 			// TODO Auto-generated catch block
    59. 			e.printStackTrace();
    60. 		}
    61. 		//表示跳到查询界面
    62. 		return "toList";
    63. 	}
    64. 	
    65. 	
    66. 	//查询
    67. 	public String list(HttpServletRequest req, HttpServletResponse resp) {
    68. 		try {
    69. 			PageBean pageBean = new PageBean();
    70. 			//初始化
    71. 			pageBean.setRequest(req);
    72. 			List<Book> list = bookDao.list(book,pageBean);
    73. 			req.setAttribute("list", list);
    74. 			req.setAttribute("pageBean", pageBean);
    75. 		} catch (Exception e) {
    76. 			// TODO Auto-generated catch block
    77. 			e.printStackTrace();
    78. 		}
    79. 		//执行查询
    80. 		return "list";
    81. 	}
    82. 	
    83. 	
    84.  
    85. 	//跳转到新增或修改界面
    86. 	public String preEdit(HttpServletRequest req, HttpServletResponse resp) {
    87. 		try {
    88. 			int bid = book.getBid();
    89. 			if(bid != 0) {
    90. 				//传递bid到后台，且只能查出一条数据，那么list集合里只有一条数据
    91. 				List<Book> list = bookDao.list(book, null);
    92. 				//id对应的值list.get(0)
    93. 				req.setAttribute("b", list.get(0));
    94. 			}
    95. 		} catch (Exception e) {
    96. 			// TODO Auto-generated catch block
    97. 			e.printStackTrace();
    98. 		}
    99. 		//表示跳到查询界面
    100. 		return "toEdit";
    101. 	}
    102. 	
    103. 	
    104. 	
    105. }

    xml配置文件

    提示：true是重定向，false是转发

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

    7.完成mvc.xml的配置

    8.完成前台代码的编写

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2. 	pageEncoding="UTF-8"%>
    3. 	<%@taglib uri="http://jsp.veryedu.cn" prefix="z"%>
    4. 	<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
    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="css/bootstrap.css"
    11. 	rel="stylesheet">
    12. <script
    13. 	src="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.  
    37. 	<form class="form-inline"
    38. 		action="${pageContext.request.contextPath}/book.action?methodName=list" method="post">
    39. 		<div class="form-group mb-2">
    40. 			<input type="text" class="form-control-plaintext" name="bname"
    41. 				placeholder="请输入书籍名称">
    42. 		</div>
    43. 		<button type="submit" class="btn btn-primary mb-2">查询</button>&nbsp;
    44. 		 <a  type="submit" class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book.action?methodName=preEdit" method="post">增加</a>
    45. 	</form>
    46.  
    47. 	<table class="table table-striped">
    48. 		<thead>
    49. 			<tr>
    50. 				<th scope="col">书籍ID</th>
    51. 				<th scope="col">书籍名</th>
    52. 				<th scope="col">价格</th>
    53. 				<th scope="col">操作</th>
    54. 			</tr>
    55. 		</thead>
    56. 		<tbody>
    57. 		<c:forEach items="${list}" var="b">
    58. 			<tr>
    59. 				<td>${b.bid}</td>
    60. 				<td>${b.bname}</td>
    61. 				<td>${b.price}</td>
    62. 				<td>
    63. 				 <a href="${pageContext.request.contextPath }/book.action?methodName=preEdit&bid=${b.bid}" method="post">编辑</a>
    64. 				 <a href="${pageContext.request.contextPath }/book.action?methodName=del&bid=${b.bid}" method="post">删除</a>
    65. 				</td>
    66. 			</tr>
    67. 			</c:forEach>
    68. 		</tbody>
    69. 	</table>
    70. 	
    71.  <z:page pagebean="${pageBean}"></z:page>
    72. 	
    73. </body>
    74. </html>

     增加和修改的界面，在action里面判断一下如果是增加就跳增加，不是则跳修改

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2.     pageEncoding="UTF-8"%>
    3. <!DOCTYPE html>
    4. <html>
    5. <head>
    6. <meta charset="UTF-8">
    7. <title>Insert title here</title>
    8. </head>
    9. <body>
    10. <form action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'update'}" method="post">
    11. 	bid:<input type="text" name="bid" value="${b.bid}"><br>
    12. 	bname:<input type="text" name="bname" value="${b.bname}"><br>
    13. 	price:<input type="text" name="price" value="${b.price}"><br>
    14. 	<input type="submit">
    15. </form>
    16. </body>
    17. </html>

    效果图如下

     

     

    修改界面 

     

    模糊查询

     

     

    提示：当效果出不来时请尝试手动输入地址栏  

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  • 原文地址：https://blog.csdn.net/weixin_66202611/article/details/125517720