• 自定义MVC增删改查

     

    目录

    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-以后开源框架的使用从这一步开始

    4.完成Book实体类及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

    9.总结

    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-以后开源框架的使用从这一步开始

                                            

                                             

    4.完成Book实体类及bookDao的编写

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

    然后用junit4去测试：

    ctrl+n

     

     

     之后就自动生成了一个BookDaoTest:

    1. package com.ycx.dao;
    2.  
    3. import static org.junit.Assert.*;
    4.  
    5. import java.util.List;
    6.  
    7. import org.junit.After;
    8. import org.junit.Before;
    9. import org.junit.Test;
    10.  
    11. import com.ycx.entity.Book;
    12.  
    13. public class BookDaoTest {
    14. 	private BookDao bookDao=new BookDao();
    15. 	@Before
    16. 	public void setUp() throws Exception {
    17. 	}
    18.  
    19. 	@After
    20. 	public void tearDown() throws Exception {
    21. 	}
    22.  
    23. 	@Test
    24. 	public void testList() {
    25. 		try {
    26. 			List<Book> list = bookDao.list(new Book(), null);
    27. 			for (Book book : list) {
    28. 				System.out.println(book);
    29. 			}
    30. 		} catch (Exception e) {
    31. 			// TODO Auto-generated catch block
    32. 			e.printStackTrace();
    33. 		}
    34. 	}
    35.  
    36. 	@Test
    37. 	public void testAdd() {
    38. 		fail("Not yet implemented");
    39. 	}
    40.  
    41. 	@Test
    42. 	public void testDel() {
    43. 		fail("Not yet implemented");
    44. 	}
    45.  
    46. 	@Test
    47. 	public void testEdit() {
    48. 		fail("Not yet implemented");
    49. 	}
    50.  
    51. }

    测试查询所有：

    打印结果如下

     

     测试分页查询：

    1. @Test
    2. 	public void testList() {
    3. 		try {
    4. 			List<Book> list = bookDao.list(new Book(), new PageBean());
    5. 			for (Book book : list) {
    6. 				System.out.println(book);
    7. 			}
    8. 		} catch (Exception e) {
    9. 			// TODO Auto-generated catch block
    10. 			e.printStackTrace();
    11. 		}
    12. 	}

    结果如下：

     测试新增数据：

    1. @Test
    2. 	public void testAdd() {
    3. 		Book book = new Book(1234321, "1234321", 1234321);
    4. 		try {
    5. 			bookDao.add(book);
    6. 		} catch (Exception e) {
    7. 			// TODO Auto-generated catch block
    8. 			e.printStackTrace();
    9. 		}
    10. 	}

    结果如下：

     测试修改：

    1. @Test
    2. 	public void testEdit() {
    3. 		Book book = new Book(1234321, "123432100", 1234321);
    4. 		try {
    5. 			bookDao.edit(book);
    6. 		} catch (Exception e) {
    7. 			// TODO Auto-generated catch block
    8. 			e.printStackTrace();
    9. 		}
    10. 	}

    结果如下：

     测试删除：

    1.  
    2. 	@Test
    3. 	public void testDel() {
    4. 		Book book = new Book(1234321, "1234321", 1234321);
    5. 		try {
    6. 			bookDao.del(book);
    7. 		} catch (Exception e) {
    8. 			// TODO Auto-generated catch block
    9. 			e.printStackTrace();
    10. 		}
    11. 	}

    5.完成通用的增删改方法

    BaseDao:

    1. 	public int executeUpdate(String sql,T t,String [] attrs) throws Exception {
    2. 		Connection con = DBAccess.getConnection();
    3. 		PreparedStatement pst = con.prepareStatement(sql);
    4. //		将T的某一个属性对应的值加到 pst 对象中
    5. 		for (int i = 0; i < attrs.length; i++) {
    6. 			Field f = t.getClass().getDeclaredField(attrs[i]);
    7. 			f.setAccessible(true);
    8. 			pst.setObject(i+1, f.get(t));
    9. 		}
    10. 		return pst.executeUpdate();
    11. 	}

    BookDao:

    1. package com.ycx.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.ycx.entity.Book;
    10. import com.ycx.util.BaseDao;
    11. import com.ycx.util.DBAccess;
    12. import com.ycx.util.PageBean;
    13. import com.ycx.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. 		String bname = book.getBname();
    20. 		if(StringUtils.isNotBlank(bname)) {
    21. 			sql+=" and bname like '%"+bname+"%'";
    22. 		}
    23. 		int bid = book.getBid();
    24. //		前台jsp传递到后台，只要传了就有值，没穿就是默认值，默认值就是0
    25. 		if(bid!=0) {
    26. 			sql+=" and bid = "+bid;
    27. 		}
    28. 		return super.executeQuery(sql, pageBean, rs ->{
    29. 			List<Book> list=new ArrayList<>();
    30. 			try {
    31. 				while(rs.next()) {
    32. 					list.add(new Book(rs.getInt("bid"),rs.getString("bname"),rs.getFloat("price")));
    33. 				}
    34. 			} catch (Exception e) {
    35. 				// TODO Auto-generated catch block
    36. 				e.printStackTrace();
    37. 			}
    38. 			return list;
    39. 		});
    40. 	}
    41. 	
    42. //	 增
    43. 	
    44. 	public int add(Book book) throws Exception {
    45. 		String sql="insert into t_mvc_book values (?,?,?)";
    46. 		return super.executeUpdate(sql, book, new String[] {"bid","bname","price"});
    47. 	}
    48. //	 删
    49. 	
    50. 	public int del(Book book) throws Exception {
    51. 		String sql="delete from t_mvc_book where bid= ?";
    52. 		return super.executeUpdate(sql, book, new String[] {"bid"});
    53. 	}
    54. 	
    55. //	 改
    56. 	
    57. 	public int edit(Book book) throws Exception {
    58. 		String sql="update t_mvc_book set bname=?,price=?, where bid=？";
    59. 		return super.executeUpdate(sql, book, new String[] {"bname","price","bid"});
    60. 	}
    61. 	
    62. 	
    63. }

    6.完成BookAction

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

    7.完成mvc.xml的配置

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

    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://ycx.com" prefix="y" %>
    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="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="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
    38. 		<div class="form-group mb-2">
    39. 			<input type="text" class="form-control-plaintext" name="bname"
    40. 				placeholder="请输入书籍名称">
    41. 		</div>
    42. 		<button type="submit" class="btn btn-primary mb-2">查询</button>
    43. 	</form>
    44.  
    45. 	<table class="table table-striped ">
    46. 		<thead>
    47. 			<tr>
    48. 				<th scope="col">书籍ID</th>
    49. 				<th scope="col">书籍名</th>
    50. 				<th scope="col">价格</th>
    51. 			</tr>
    52. 		</thead>
    53. 		<tbody>
    54. 			<c:forEach items="${list }" var="b">
    55. 			<tr>
    56. 				<td>${b.bid }</td>
    57. 				<td>${b.bname }</td>
    58. 				<td>${b.price }</td>
    59. 			</tr>
    60. 			</c:forEach>
    61. 		</tbody>
    62. 	</table>
    63. 	
    64. 	<y:page pageBean="${pageBean }"></y:page>
    65. 	
    66.  
    67. </body>
    68. </html>

     

     

    9.总结

    自定义MVC框架应用中最为关键的是要把自定义MVC框架打造好，其中在应用是也要注意细节，比如：改造.xml文件时要跳转的目的类。

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  • 原文地址：https://blog.csdn.net/weixin_65808248/article/details/125513427