• 自定义mvc框架实现

    文章目录

    一、中央控制器动态加载存储子控制器

    分析：

    1.通过建模我们可以知道，最终configModel对象会包含config.xml中所有子控制器的信息

    2.同时为了解决中央控制器能够动态加载保存子控制器的信息，那么我们只需要引入congigModel对象即可

    代码展示：

    config.xml

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <config>
    3. 	<action path="/book" type="com.cdl.web.BookAction">
    4. 		<forward name="failed" path="/reg.jsp" redirect="false" />
    5. 		<forward name="success" path="/login.jsp" redirect="true" />
    6. 	</action>
    7. 	
    8. </config>

    对DispatcherServlet进行改造

    1. package com.cdl.framework;
    2.  
    3. import java.io.IOException;
    4. import java.util.HashMap;
    5. import java.util.Map;
    6.  
    7. import javax.management.RuntimeErrorException;
    8. import javax.servlet.ServletException;
    9. import javax.servlet.annotation.WebServlet;
    10. import javax.servlet.http.HttpServlet;
    11. import javax.servlet.http.HttpServletRequest;
    12. import javax.servlet.http.HttpServletResponse;
    13.  
    14. import com.cdl.web.BookAction;
    15.  
    16.  
    17.  
    18. /**
    19.  * 中央控制器：
    20.  * 主要职能：接受浏览器请求，找到对应的处理人
    21.  *
    22.  * 
    23.  * @author 陈冬丽
    24.  *
    25.  */
    26. @WebServlet("*.action")
    27. public class DispatcherServlet extends HttpServlet{
    28. 	//private Map<String, Action> actions=new HashMap<String, Action>();
    29. 	
    30. //	通过建模我们可以知道，最终configModel对象会包含config.xml中所有子控制器的信息
    31. //	同时为了解决中央控制器能够动态加载保存子控制器的信息，那么我们只需要引入congigModel对象即可
    32. 	private ConfigModel ConfigModel;
    33. 	
    34. 	
    35. 	
    36. 	//	程序启动时，只会加载一次
    37. 	@Override
    38. 	public void init() throws ServletException {
    39. 		//actions.put("/book", new BookAction());
    40. //		actions.put("/order", new BooKAction());
    41. 		try {
    42. 			ConfigModel = (ConfigModel)ConfigModelFactory.bulid();
    43. 		} catch (Exception e) {
    44. 			// TODO Auto-generated catch block
    45. 			e.printStackTrace();
    46. 		}
    47. 	}
    48. 	
    49. 	@Override
    50. 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    51. 		doPost(req, resp);
    52. 	}
    53. 	@Override
    54. 	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    55. 		//http://localhost:8080/mvc/book.aciton?methodName=list
    56. 		String uri = req.getRequestURI();
    57. //		要拿到/book，就是最后一个/到最后一个点的位置
    58. 		uri=uri.substring(uri.lastIndexOf("/")
    59. 						, uri.lastIndexOf("."));
    60. 		//Action action = actions.get(uri);
    61. 		//相比于上一种从map集合中获取子控制器，当前需要获取config.xml中的全路径名，然后反射实例化
    62. 		ActionModel actionModel = ConfigModel.pop(uri);
    63. 		if(actionModel == null) {
    64. 			throw new RuntimeException("action 配置 error");
    65. 		}
    66. 		String type = actionModel.getType();//配置文件中的全路径名 action子控制器的全路径名
    67. 		try {
    68. 			Action action = (Action) Class.forName(type).newInstance();//action的实例
    69. 			action.execute(req, resp);
    70. 		} catch (Exception e) {
    71. 			e.printStackTrace();
    72. 		} 
    73. 	}
    74. 	
    75. }

    页面代码：Demo01

    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. <h3>优化</h3>
    11. <a href="${pageContext.request.contextPath }/book.action?methodName=add">增加</a>
    12. <a href="${pageContext.request.contextPath }/book.action?methodName=del">删除</a>
    13. <a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
    14. <a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
    15. <a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
    16. </body>
    17. </html>

     运行效果：

     点击增加

    二、参数传递封装的优化

    以增加为例

    Demo01:

    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. <h3>参数传递封装的优化</h3>
    11. <a href="${pageContext.request.contextPath }/book.action?methodName=add&bid=989898&bname=laoliu&price=89">增加</a>
    12. <a href="${pageContext.request.contextPath }/book.action?methodName=del">删除</a>
    13. <a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
    14. <a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
    15. <a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
    16. </body>
    17. </html>

    建一个com.cdl.entity的包 在其内建一个Book的实体类

    1. package com.cdl.entity;
    2. /**
    3.  * 书的实体类
    4.  * @author 陈冬丽
    5.  *
    6.  */
    7. public class Book {
    8. 	private int bid;
    9. 	private String bname;
    10. 	private float price;
    11. 	
    12. 	public int getBid() {
    13. 		return bid;
    14. 	}
    15. 	public void setBid(int bid) {
    16. 		this.bid = bid;
    17. 	}
    18. 	public String getBname() {
    19. 		return bname;
    20. 	}
    21. 	public void setBname(String bname) {
    22. 		this.bname = bname;
    23. 	}
    24. 	public float getPrice() {
    25. 		return price;
    26. 	}
    27. 	public void setPrice(float price) {
    28. 		this.price = price;
    29. 	}
    30. 	@Override
    31. 	public String toString() {
    32. 		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
    33. 	}
    34. 	
    35. }

    优化前的BookAction

    1. package com.cdl.web;
    2.  
    3. import javax.servlet.http.HttpServletRequest;
    4. import javax.servlet.http.HttpServletResponse;
    5.  
    6. import com.cdl.entity.Book;
    7. import com.cdl.framework.Action;
    8. import com.cdl.framework.ActionSupport;
    9.  
    10. public class BookAction extends ActionSupport {
    11. 	
    12. 	private void list(HttpServletRequest req, HttpServletResponse resp) {
    13. 		System.out.println("在用一个servlet中调用 list 方法");
    14. 	}
    15. 	
    16. 	private void load(HttpServletRequest req, HttpServletResponse resp) {
    17. 		System.out.println("在用一个servlet中调用 list 方法");
    18. 	}
    19. 	
    20. 	private void edit(HttpServletRequest req, HttpServletResponse resp) {
    21. 		System.out.println("在用一个servlet中调用 edit 方法");
    22. 	}
    23.  
    24. 	private void del(HttpServletRequest req, HttpServletResponse resp) {
    25. 		System.out.println("在用一个servlet中调用 del 方法");
    26. 	}
    27.  
    28. 	private void add(HttpServletRequest req, HttpServletResponse resp) {
    29. 		String bid = req.getParameter("bid");
    30. 		String bname = req.getParameter("bname");
    31. 		String price = req.getParameter("price");
    32. 		Book book = new Book();
    33. 		book.setBid(Integer.valueOf(bid));
    34. 		book.setBname(bname);
    35. 		book.setPrice(Float.valueOf(price));
    36. 		System.out.println("在用一个servlet中调用 add 方法"+book);
    37. 	}
    38. }
    39.

    在界面点击增加之后：

     

     问题：若前端也就是界面联合了多张表，那么在传递参数时就不止3个属性，就会反复的写String bname = req.getParameter("bname"); 这种代码

    BookAction

    1. package com.cdl.web;
    2.  
    3. import javax.servlet.http.HttpServletRequest;
    4. import javax.servlet.http.HttpServletResponse;
    5.  
    6. import com.cdl.entity.Book;
    7. import com.cdl.framework.Action;
    8. import com.cdl.framework.ActionSupport;
    9. import com.cdl.framework.ModelDriven;
    10. /**
    11.  * 子控制器
    12.  * @author 陈冬丽
    13.  *
    14.  *
    15.  */
    16. public class BookAction extends ActionSupport implements ModelDriven<Book>{
    17. 	
    18. 	private Book book = new Book();
    19. 	
    20. 	private void list(HttpServletRequest req, HttpServletResponse resp) {
    21. 		System.out.println("在用一个servlet中调用 list 方法");
    22. 	}
    23. 	
    24. 	private void load(HttpServletRequest req, HttpServletResponse resp) {
    25. 		System.out.println("在用一个servlet中调用 list 方法");
    26. 	}
    27. 	
    28. 	private void edit(HttpServletRequest req, HttpServletResponse resp) {
    29. 		System.out.println("在用一个servlet中调用 edit 方法");
    30. 	}
    31.  
    32. 	private void del(HttpServletRequest req, HttpServletResponse resp) {
    33. 		System.out.println("在用一个servlet中调用 del 方法");
    34. 	}
    35.  
    36. 	private void add(HttpServletRequest req, HttpServletResponse resp) {
    37. //		String bid = req.getParameter("bid");
    38. //		String bname = req.getParameter("bname");
    39. //		String price = req.getParameter("price");
    40. 		//Book book = new Book();
    41. //		book.setBid(Integer.valueOf(bid));
    42. //		book.setBname(bname);
    43. //		book.setPrice(Float.valueOf(price));
    44. 		System.out.println("在用一个servlet中调用 add 方法"+book);
    45. 	}
    46.  
    47. 	@Override
    48. 	public Book getModel() {
    49. 		return book;
    50. 	}
    51. }
    52.

    创建一个接口ModelDriven

    1. package com.cdl.framework;
    2. /**
    3.  * 模型驱动接口：接收jsp传递的参数，并且封装到实体类中
    4.  * @author 陈冬丽
    5.  *
    6.  *
    7.  */
    8. public interface ModelDriven<T> {
    9. 	//拿到将要封装的类实例 ModelDriven.getModel -->new Book();
    10. 	T getModel();
    11. }

    改造 DispatcherServlet

    1. package com.cdl.framework;
    2.  
    3. import java.io.IOException;
    4. import java.util.HashMap;
    5. import java.util.Map;
    6.  
    7. import javax.management.RuntimeErrorException;
    8. import javax.servlet.ServletException;
    9. import javax.servlet.annotation.WebServlet;
    10. import javax.servlet.http.HttpServlet;
    11. import javax.servlet.http.HttpServletRequest;
    12. import javax.servlet.http.HttpServletResponse;
    13.  
    14. import org.apache.commons.beanutils.BeanUtils;
    15. import org.apache.commons.beanutils.PropertyUtils;
    16.  
    17. import com.cdl.web.BookAction;
    18.  
    19.  
    20.  
    21. /**
    22.  * 中央控制器：
    23.  * 主要职能：接受浏览器请求，找到对应的处理人
    24.  * 
    25.  * @author 陈冬丽
    26.  *
    27.  */
    28. @WebServlet("*.action")
    29. public class DispatcherServlet extends HttpServlet{
    30. 	//private Map<String, Action> actions=new HashMap<String, Action>();
    31. 	
    32. //	通过建模我们可以知道，最终configModel对象会包含config.xml中所有子控制器的信息
    33. //	同时为了解决中央控制器能够动态加载保存子控制器的信息，那么我们只需要引入congigModel对象即可
    34. 	private ConfigModel ConfigModel;
    35. 	
    36. 	
    37. 	
    38. 	//	程序启动时，只会加载一次
    39. 	@Override
    40. 	public void init() throws ServletException {
    41. 		//actions.put("/book", new BookAction());
    42. //		actions.put("/order", new BooKAction());
    43. 		try {
    44. 			ConfigModel = (ConfigModel)ConfigModelFactory.bulid();
    45. 		} catch (Exception e) {
    46. 			// TODO Auto-generated catch block
    47. 			e.printStackTrace();
    48. 		}
    49. 	}
    50. 	
    51. 	@Override
    52. 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    53. 		doPost(req, resp);
    54. 	}
    55. 	@Override
    56. 	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    57. 		//http://localhost:8080/mvc/book.aciton?methodName=list
    58. 		String uri = req.getRequestURI();
    59. //		要拿到/book，就是最后一个/到最后一个点的位置
    60. 		uri=uri.substring(uri.lastIndexOf("/")
    61. 						, uri.lastIndexOf("."));
    62. 		//Action action = actions.get(uri);
    63. 		//相比于上一种从map集合中获取子控制器，当前需要获取config.xml中的全路径名，然后反射实例化
    64. 		ActionModel actionModel = ConfigModel.pop(uri);
    65. 		if(actionModel == null) {
    66. 			throw new RuntimeException("action 配置 error");
    67. 		}
    68. 		String type = actionModel.getType();//配置文件中的全路径名 action子控制器的全路径名
    69. 		try {
    70. 			Action action = (Action) Class.forName(type).newInstance();//action的实例
    71. 			//因为action是bookAction而bookAction实现了ModelDriven接口
    72. 			if(action instanceof ModelDriven) {
    73. 				//所以可以将其进行向下转型
    74. 				ModelDriven md = (ModelDriven)action;
    75. 				//model指的是bookAction中的book类实例
    76. 				Object model = md.getModel();
    77. 				//给model中的属性赋值,要接受前端jsp传递的参数  req.getParameterMap()
    78. 				//PropertyUtils.getIndexedProperty(bean, name) 从某个对象中取某个值
    79. 				
    80. 				//将前端所有参数值封装进实体类
    81. 				BeanUtils.populate(model, req.getParameterMap());
    82. 				
    83. 			}
    84. //			目标：正式调用此方法之前 book中的属性要被赋值
    85. 			action.execute(req, resp);
    86. 		} catch (Exception e) {
    87. 			e.printStackTrace();
    88. 		} 
    89. 	}
    90. 	
    91. }

    当在页面点击增加和优化前一样的效果

    三、返回值页面跳转优化

    对子控制器进行改造

    1. package com.cdl.framework;
    2.  
    3. import javax.servlet.http.HttpServletRequest;
    4. import javax.servlet.http.HttpServletResponse;
    5.  
    6. /**
    7.  * 子控制器：
    8.  * 对应请求的处理人
    9.  * @author 陈冬丽
    10.  *
    11.  */
    12. public interface Action {
    13. 	String execute(HttpServletRequest req, HttpServletResponse resp);
    14. }
    15.

    ActionSupport

    1. package com.cdl.framework;
    2.  
    3. import java.lang.reflect.Method;
    4.  
    5. import javax.servlet.http.HttpServletRequest;
    6. import javax.servlet.http.HttpServletResponse;
    7.  
    8. public class ActionSupport implements Action{
    9.  
    10. 	@Override
    11. 	public String execute(HttpServletRequest req, HttpServletResponse resp) {
    12. 		String methodName = req.getParameter("methodName");
    13. //		methodName可能是add/del/edit/list/load/xxx/yyy/aaa...
    14. //		前台传递什么方法，就调用当前类的对应方法
    15. 		try {
    16. 			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
    17. 			m.setAccessible(true);
    18. //			调用当前类实例的methodName方法
    19. 			return (String) m.invoke(this, req,resp);
    20. 		} catch (Exception e) {
    21. 			// TODO Auto-generated catch block
    22. 			e.printStackTrace();
    23. 		}
    24. 		return null; 
    25. 	}
    26. 	
    27. 	private void list(HttpServletRequest req, HttpServletResponse resp) {
    28. 		System.out.println("在用一个servlet中调用 list 方法");
    29. 	}
    30. 	
    31. 	private void load(HttpServletRequest req, HttpServletResponse resp) {
    32. 		System.out.println("在用一个servlet中调用 list 方法");
    33. 	}
    34. 	
    35. 	private void edit(HttpServletRequest req, HttpServletResponse resp) {
    36. 		System.out.println("在用一个servlet中调用 edit 方法");
    37. 	}
    38.  
    39. 	private void del(HttpServletRequest req, HttpServletResponse resp) {
    40. 		System.out.println("在用一个servlet中调用 del 方法");
    41. 	}
    42.  
    43. 	private void add(HttpServletRequest req, HttpServletResponse resp) {
    44. 		System.out.println("在用一个servlet中调用 add 方法");
    45. 	}
    46. }

    DispatcherServlet

    1. package com.cdl.framework;
    2.  
    3. import java.io.IOException;
    4. import java.util.HashMap;
    5. import java.util.Map;
    6.  
    7. import javax.management.RuntimeErrorException;
    8. import javax.servlet.ServletException;
    9. import javax.servlet.annotation.WebServlet;
    10. import javax.servlet.http.HttpServlet;
    11. import javax.servlet.http.HttpServletRequest;
    12. import javax.servlet.http.HttpServletResponse;
    13.  
    14. import org.apache.commons.beanutils.BeanUtils;
    15. import org.apache.commons.beanutils.PropertyUtils;
    16.  
    17. import com.cdl.web.BookAction;
    18.  
    19.  
    20.  
    21. /**
    22.  * 中央控制器：
    23.  * 主要职能：接受浏览器请求，找到对应的处理人
    24.  * 
    25.  * @author 陈冬丽
    26.  *
    27.  */
    28. @WebServlet("*.action")
    29. public class DispatcherServlet extends HttpServlet{
    30. 	//private Map<String, Action> actions=new HashMap<String, Action>();
    31. 	
    32. //	通过建模我们可以知道，最终configModel对象会包含config.xml中所有子控制器的信息
    33. //	同时为了解决中央控制器能够动态加载保存子控制器的信息，那么我们只需要引入congigModel对象即可
    34. 	private ConfigModel ConfigModel;
    35. 	
    36. 	
    37. 	
    38. 	//	程序启动时，只会加载一次
    39. 	@Override
    40. 	public void init() throws ServletException {
    41. 		//actions.put("/book", new BookAction());
    42. //		actions.put("/order", new BooKAction());
    43. 		try {
    44. 			ConfigModel = (ConfigModel)ConfigModelFactory.bulid();
    45. 		} catch (Exception e) {
    46. 			// TODO Auto-generated catch block
    47. 			e.printStackTrace();
    48. 		}
    49. 	}
    50. 	
    51. 	@Override
    52. 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    53. 		doPost(req, resp);
    54. 	}
    55. 	@Override
    56. 	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    57. 		//http://localhost:8080/mvc/book.aciton?methodName=list
    58. 		String uri = req.getRequestURI();
    59. //		要拿到/book，就是最后一个/到最后一个点的位置
    60. 		uri=uri.substring(uri.lastIndexOf("/")
    61. 						, uri.lastIndexOf("."));
    62. 		//Action action = actions.get(uri);
    63. 		//相比于上一种从map集合中获取子控制器，当前需要获取config.xml中的全路径名，然后反射实例化
    64. 		ActionModel actionModel = ConfigModel.pop(uri);
    65. 		if(actionModel == null) {
    66. 			throw new RuntimeException("action 配置 error");
    67. 		}
    68. 		String type = actionModel.getType();//配置文件中的全路径名 action子控制器的全路径名
    69. 		try {
    70. 			Action action = (Action) Class.forName(type).newInstance();//action的实例
    71. 			//因为action是bookAction而bookAction实现了ModelDriven接口
    72. 			if(action instanceof ModelDriven) {
    73. 				//所以可以将其进行向下转型
    74. 				ModelDriven md = (ModelDriven)action;
    75. 				//model指的是bookAction中的book类实例
    76. 				Object model = md.getModel();
    77. 				//给model中的属性赋值,要接受前端jsp传递的参数  req.getParameterMap()
    78. 				//PropertyUtils.getIndexedProperty(bean, name) 从某个对象中取某个值
    79. 				
    80. 				//将前端所有参数值封装进实体类
    81. 				BeanUtils.populate(model, req.getParameterMap());
    82. 				
    83. 			}
    84. //			正式调用此方法之前 book中的属性要被赋值
    85. 			String result = action.execute(req,resp);
    86. 			ForwardModel forwardModel = actionModel.pop(result);
    87. //			if(forwardModel == null)
    88. //				throw new RuntimeException("forward config error");
    89. //			/bookList.jsp /index.jsp
    90. 			String path = forwardModel.getPath();
    91. 			//拿到是否需要转发的配置
    92. 			boolean redirect = forwardModel.isRedirect();
    93. 			if(redirect)
    94. 				resp.sendRedirect(path);
    95. 			else
    96. 			req.getRequestDispatcher(path).forward(req, resp);
    97. 			
    98. 		} catch (Exception e) {
    99. 			e.printStackTrace();
    100. 		} 
    101. 	}
    102. 	
    103. }

    ForwardModel

    1. package com.cdl.framework;
    2.  
    3. /**
    4.  * @author 陈冬丽
    5.  *
    6.  */
    7. public class ForwardModel {
    8. //	<forward name="failed" path="/reg.jsp" redirect="false" />
    9. 	private String name;
    10. 	private String path;
    11. 	private Boolean redirect;
    12. 	public String getName() {
    13. 		return name;
    14. 	}
    15. 	public void setName(String name) {
    16. 		this.name = name;
    17. 	}
    18. 	public String getPath() {
    19. 		return path;
    20. 	}
    21. 	public void setPath(String path) {
    22. 		this.path = path;
    23. 	}
    24. 	public Boolean getRedirect() {
    25. 		return redirect;
    26. 	}
    27. 	public void setRedirect(Boolean redirect) {
    28. 		this.redirect = redirect;
    29. 	}
    30. 	
    31. 	public ForwardModel() {
    32. 		// TODO Auto-generated constructor stub
    33. 	}
    34. 	public ForwardModel(String name, String path, Boolean redirect) {
    35. 		this.name = name;
    36. 		this.path = path;
    37. 		this.redirect = redirect;
    38. 	}
    39. 	public boolean isRedirect() {
    40. 		return redirect;
    41. 	}
    42. 	
    43. 	
    44. 	
    45. 	
    46. }

    config.xml

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <config>
    3. 	<action path="/book" type="com.cdl.web.BookAction">
    4. 		<forward name="success" path="/Demo02.jsp" redirect="false" />
    5. 		<forward name="failed" path="/Demo03.jsp" redirect="true" />
    6. 	</action>
    7. 	
    8. 	<action path="/order" type="com.cdl.web.OrderAction">
    9. 		<forward name="failed" path="/reg.jsp" redirect="false" />
    10. 		<forward name="success" path="/login.jsp" redirect="true" />
    11. 	</action>
    12. </config>

    界面Demo01

    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. <h3>参数传递封装的优化</h3>
    11. <a href="${pageContext.request.contextPath }/book.action?methodName=add&bid=989898&bname=laoliu&price=89">增加</a>
    12. <a href="${pageContext.request.contextPath }/book.action?methodName=del">删除</a>
    13. <a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
    14. <a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
    15. <a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
    16.  
    17. </body>
    18. </html>

    Demo02

    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. 	转发页面
    11. </body>
    12. </html>

    Demo03

    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. 重定向页面
    11. </body>
    12. </html>

    运行Demo01

     点击增加

     点击查询

     丢失项目名的解决办法

    代码段：

    DispatcherServlet

    1. //拿到是否需要转发的配置
    2. 			boolean redirect = forwardModel.isRedirect();
    3. 			if(redirect)
    4. 				resp.sendRedirect(req.getServletContext().getContextPath()+path);
    5. 			else
    6. 			req.getRequestDispatcher(path).forward(req, resp);

    再次点击增加时

     此时控制台：

     注意：即使在丢失项目名的情况下 还是会调用增加的方法

    四、框架配置文件可变

    DispatcherServlet

    1. package com.cdl.framework;
    2.  
    3. import java.io.IOException;
    4. import java.util.HashMap;
    5. import java.util.Map;
    6.  
    7. import javax.management.RuntimeErrorException;
    8. import javax.servlet.ServletException;
    9. import javax.servlet.annotation.WebServlet;
    10. import javax.servlet.http.HttpServlet;
    11. import javax.servlet.http.HttpServletRequest;
    12. import javax.servlet.http.HttpServletResponse;
    13.  
    14. import org.apache.commons.beanutils.BeanUtils;
    15. import org.apache.commons.beanutils.PropertyUtils;
    16.  
    17. import com.cdl.web.BookAction;
    18.  
    19.  
    20.  
    21. /**
    22.  * 中央控制器：
    23.  * 主要职能：接受浏览器请求，找到对应的处理人
    24.  * 
    25.  * @author 陈冬丽
    26.  *
    27.  */
    28. //@WebServlet("*.action")
    29. public class DispatcherServlet extends HttpServlet{
    30. 	//private Map<String, Action> actions=new HashMap<String, Action>();
    31. 	
    32. //	通过建模我们可以知道，最终configModel对象会包含config.xml中所有子控制器的信息
    33. //	同时为了解决中央控制器能够动态加载保存子控制器的信息，那么我们只需要引入congigModel对象即可
    34. 	private ConfigModel ConfigModel;
    35. 	
    36. 	
    37. 	
    38. 	//	程序启动时，只会加载一次
    39. 	@Override
    40. 	public void init() throws ServletException {
    41. 		//actions.put("/book", new BookAction());
    42. //		actions.put("/order", new BooKAction());
    43. 		try {
    44. 			//配置地址
    45. 			//getInitParameter的作用是拿到web.xml中的servlet信息配置的参数
    46. 			String configLocation = this.getInitParameter("configLocation");
    47. 			if(configLocation == null || "".equals(configLocation))
    48. 				ConfigModel = ConfigModelFactory.bulid();
    49. 			else
    50. 				ConfigModel = ConfigModelFactory.bulid(configLocation);
    51. 		} catch (Exception e) {
    52. 			// TODO Auto-generated catch block
    53. 			e.printStackTrace();
    54. 		}
    55. 	}
    56. 	
    57. 	@Override
    58. 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    59. 		doPost(req, resp);
    60. 	}
    61. 	@Override
    62. 	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    63. 		//http://localhost:8080/mvc/book.aciton?methodName=list
    64. 		String uri = req.getRequestURI();
    65. //		要拿到/book，就是最后一个/到最后一个点的位置
    66. 		uri=uri.substring(uri.lastIndexOf("/")
    67. 						, uri.lastIndexOf("."));
    68. 		//Action action = actions.get(uri);
    69. 		//相比于上一种从map集合中获取子控制器，当前需要获取config.xml中的全路径名，然后反射实例化
    70. 		ActionModel actionModel = ConfigModel.pop(uri);
    71. 		if(actionModel == null) {
    72. 			throw new RuntimeException("action 配置 error");
    73. 		}
    74. 		String type = actionModel.getType();//配置文件中的全路径名 action子控制器的全路径名
    75. 		try {
    76. 			Action action = (Action) Class.forName(type).newInstance();//action的实例
    77. 			//因为action是bookAction而bookAction实现了ModelDriven接口
    78. 			if(action instanceof ModelDriven) {
    79. 				//所以可以将其进行向下转型
    80. 				ModelDriven md = (ModelDriven)action;
    81. 				//model指的是bookAction中的book类实例
    82. 				Object model = md.getModel();
    83. 				//给model中的属性赋值,要接受前端jsp传递的参数  req.getParameterMap()
    84. 				//PropertyUtils.getIndexedProperty(bean, name) 从某个对象中取某个值
    85. 				
    86. 				//将前端所有参数值封装进实体类
    87. 				BeanUtils.populate(model, req.getParameterMap());
    88. 				
    89. 			}
    90. //			正式调用此方法之前 book中的属性要被赋值
    91. 			String result = action.execute(req,resp);
    92. 			ForwardModel forwardModel = actionModel.pop(result);
    93. //			if(forwardModel == null)
    94. //				throw new RuntimeException("forward config error");
    95. //			/bookList.jsp /index.jsp
    96. 			String path = forwardModel.getPath();
    97. 			//拿到是否需要转发的配置
    98. 			boolean redirect = forwardModel.isRedirect();
    99. 			if(redirect)
    100. 				resp.sendRedirect(req.getServletContext().getContextPath()+path);
    101. 			else
    102. 			req.getRequestDispatcher(path).forward(req, resp);
    103. 			
    104. 		} catch (Exception e) {
    105. 			e.printStackTrace();
    106. 		} 
    107. 	}
    108. 	
    109. }

    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_mvc</display-name>
    4.   <servlet>
    5.   	<servlet-name>mvc</servlet-name>
    6.   	<servlet-class>com.cdl.framework.DispatcherServlet</servlet-class>
    7.  	<init-param>
    8.  		<param-name>configLaction</param-name>
    9.  		<param-value>/wuyanzu</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>

     将config.xml->wuyanzu.xml

    运行Demo01点击增加和查询和三是一样的结果


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  • 原文地址：https://blog.csdn.net/weixin_62735525/article/details/125488668