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servlet

Wesley13

2021-10-11

1453 0 0

思路分析：
1. 根据需求抽象出业务对象
User{
usrename;
password;
}

ShoppingCarItem{
product;
num;
}

ShoppingCar{
List<ShoppingCarItem>
}

2. 写Servlet处理请求
...

domain:

Java代码 复制代码 收藏代码

  1. package cn.itcast.cd.domain;

  2. import java.util.ArrayList;

  3. import java.util.List;

  4. import java.util.UUID;

  5. public class ShoppingCar {

  6. private List<ShoppingCarItem> list = new ArrayList<ShoppingCarItem>();

  7. /**

  8. * 根据货品和数量往购物车中添加

  9. * @param product

  10. * @param num

  11. */

  12. public void add(String product,Integer num){

  13. ShoppingCarItem carItem = new ShoppingCarItem();

  14. carItem.setNum(num);

  15. carItem.setProduct(product);

  16. carItem.setId(UUID.randomUUID().toString());

  17. list.add(carItem);

  18. }

  19. /**

  20. * 根据唯一的标示删除购物车中对应的明细

  21. * @param id

  22. */

  23. public void remove(String id){

  24. for (ShoppingCarItem item : list) {

  25. if(id.equals(item.getId())){

  26. list.remove(item);

  27. break;

  28. }

  29. }

  30. }

  31. public List<ShoppingCarItem> getList() {

  32. return list;

  33. }

  34. }

  35. package cn.itcast.cd.domain;

  36. public class ShoppingCarItem {

  37. private String product;

  38. private Integer num;

  39. private String id; //给每一个明细生成一个唯一的id

  40. public String getProduct() {

  41. return product;

  42. }

  43. public void setProduct(String product) {

  44. this.product = product;

  45. }

  46. public Integer getNum() {

  47. return num;

  48. }

  49. public void setNum(Integer num) {

  50. this.num = num;

  51. }

  52. public String getId() {

  53. return id;

  54. }

  55. public void setId(String id) {

  56. this.id = id;

  57. }

  58. }

  59. package cn.itcast.cd.domain;

  60. public class User {

  61. private String username;

  62. private String password;

  63. public String getUsername() {

  64. return username;

  65. }

  66. public void setUsername(String username) {

  67. this.username = username;

  68. }

  69. public String getPassword() {

  70. return password;

  71. }

  72. public void setPassword(String password) {

  73. this.password = password;

  74. }

  75. }

package cn.itcast.cd.domain;

1import java.util.ArrayList;
2import java.util.List;
3import java.util.UUID;
4
5public class ShoppingCar {
6	private List<ShoppingCarItem> list = new ArrayList<ShoppingCarItem>();
7	
8	/**
9	 * 根据货品和数量往购物车中添加
10	 * @param product
11	 * @param num
12	 */
13	public void add(String product,Integer num){
14		ShoppingCarItem carItem = new ShoppingCarItem();
15		carItem.setNum(num);
16		carItem.setProduct(product);
17		carItem.setId(UUID.randomUUID().toString());
18		list.add(carItem);
19	}
20	
21	/**
22	 * 根据唯一的标示删除购物车中对应的明细
23	 * @param id
24	 */
25	public void remove(String id){
26		for (ShoppingCarItem item : list) {
27			 if(id.equals(item.getId())){
28				 list.remove(item);
29				 break;
30			 }
31		}
32	}	
33	
34	public List<ShoppingCarItem> getList() {
35		return list;
36	}
37	
38}
39
40package cn.itcast.cd.domain;
41
42public class ShoppingCarItem {
43	private String product;
44	private Integer  num;
45	private String id;  //给每一个明细生成一个唯一的id
46	public String getProduct() {
47		return product;
48	}
49	public void setProduct(String product) {
50		this.product = product;
51	}
52	public Integer getNum() {
53		return num;
54	}
55	public void setNum(Integer num) {
56		this.num = num;
57	}
58	public String getId() {
59		return id;
60	}
61	public void setId(String id) {
62		this.id = id;
63	}
64	
65}
66
67package cn.itcast.cd.domain;
68
69public class User {
70	private String username;
71	private String password;
72	public String getUsername() {
73		return username;
74	}
75	public void setUsername(String username) {
76		this.username = username;
77	}
78	public String getPassword() {
79		return password;
80	}
81	public void setPassword(String password) {
82		this.password = password;
83	}
84}

servlet:

Java代码 复制代码 收藏代码

  1. package cn.itcast.cd.servlet;

  2. import java.io.IOException;

  3. import java.io.PrintWriter;

  4. import javax.servlet.ServletException;

  5. import javax.servlet.http.HttpServlet;

  6. import javax.servlet.http.HttpServletRequest;

  7. import javax.servlet.http.HttpServletResponse;

  8. import javax.servlet.http.HttpSession;

  9. import cn.itcast.cd.domain.ShoppingCar;

  10. public class BuyServlet extends HttpServlet {

  11. @Override

  12. protected void service(HttpServletRequest request, HttpServletResponse response)

  13. throws ServletException, IOException {

  14. request.setCharacterEncoding("UTF-8");

  15. response.setContentType("text/html;charset=utf-8");

  16. //1. 获取请求中的参数.

  17. String product = request.getParameter("product");

  18. String num = request.getParameter("num");

  19. //2. 获取到购物车

  20. //2.1 首先要到session中找一下是否已经有了购物车. 如果有的话就不需要创建了... 直接把货品放到购物车中就可以了

  21. HttpSession httpSession = request.getSession();

  22. ShoppingCar shoppingCar = (ShoppingCar)httpSession.getAttribute("SHOPINGCAR_IN_SESSION");

  23. if(shoppingCar==null){ //说明是第一次购物. 还没有购物车的

  24. //2.2 如果从session中没有找到购物车. 需要新创建一个购物车并且放到session中.为了下次购物使用这个购物车

  25. shoppingCar = new ShoppingCar();

  26. httpSession.setAttribute("SHOPINGCAR_IN_SESSION", shoppingCar);

  27. }

  28. shoppingCar.add(product, Integer.parseInt(num));

  29. PrintWriter pw = response.getWriter();

  30. pw.println("添加成功<br/>");

  31. pw.println("<a href='/buy.html'>继续购物</a><br/>");

  32. pw.println("<a href='/list'>管理购物</a><br/>");

  33. }

  34. }

  35. package cn.itcast.cd.servlet;

  36. import java.io.IOException;

  37. import java.io.PrintWriter;

  38. import javax.servlet.ServletException;

  39. import javax.servlet.http.HttpServlet;

  40. import javax.servlet.http.HttpServletRequest;

  41. import javax.servlet.http.HttpServletResponse;

  42. import javax.servlet.http.HttpSession;

  43. import cn.itcast.cd.domain.ShoppingCar;

  44. import cn.itcast.cd.domain.ShoppingCarItem;

  45. import cn.itcast.cd.domain.User;

  46. public class ListServlet extends HttpServlet {

  47. @Override

  48. protected void service(HttpServletRequest request, HttpServletResponse response)

  49. throws ServletException, IOException {

  50. request.setCharacterEncoding("UTF-8");

  51. response.setContentType("text/html;charset=utf-8");

  52. HttpSession httpSession = request.getSession();

  53. //1. 先获取session中的User

  54. User user = (User) httpSession.getAttribute("USER_IN_SESSION");

  55. PrintWriter pw = response.getWriter();

  56. pw.println("当前用户为:"+user.getUsername()+"<br/>");

  57. //2. 获取session的购物车

  58. ShoppingCar shoppingCar = (ShoppingCar) httpSession.getAttribute("SHOPINGCAR_IN_SESSION");

  59. //2.1 如果在session中购物车的话,列出购物车中的明细

  60. if(shoppingCar!=null){

  61. for (ShoppingCarItem item : shoppingCar.getList()) {

  62. pw.println("货品:"+item.getProduct()+" 数量:"+item.getNum()+"<br/>");

  63. }

  64. }else{

  65. //2.2 在session中没有购物车的话.提示用户没有当前用户名购物车

  66. pw.println("当前用户没有购物车.");

  67. }

  68. }

  69. }

  70. package cn.itcast.cd.servlet;

  71. import java.io.IOException;

  72. import java.io.PrintWriter;

  73. import javax.servlet.ServletException;

  74. import javax.servlet.http.HttpServlet;

  75. import javax.servlet.http.HttpServletRequest;

  76. import javax.servlet.http.HttpServletResponse;

  77. import javax.servlet.http.HttpSession;

  78. import cn.itcast.cd.domain.User;

  79. public class LoginServlet extends HttpServlet {

  80. @Override

  81. protected void service(HttpServletRequest request, HttpServletResponse response)

  82. throws ServletException, IOException {

  83. request.setCharacterEncoding("UTF-8");

  84. response.setContentType("text/html;charset=utf-8");

  85. //1. 接收请求中的数据封装对象

  86. String username = request.getParameter("username");

  87. String password = request.getParameter("password");

  88. User user = new User();

  89. user.setPassword(password);

  90. user.setUsername(username);

  91. //2. 将用户方到session中供ListServlet从session中访问到User

  92. HttpSession httpSession = request.getSession();

  93. httpSession.setAttribute("USER_IN_SESSION", user);

  94. PrintWriter pw = response.getWriter();

  95. pw.println("欢迎:"+username+"<br/>");

  96. pw.println("<a href='/buy.html'>购物</a><br/>");

  97. pw.println("<a href='/list'>管理购物</a><br/>");

  98. }

  99. }

package cn.itcast.cd.servlet;

1import java.io.IOException;
2import java.io.PrintWriter;
3
4import javax.servlet.ServletException;
5import javax.servlet.http.HttpServlet;
6import javax.servlet.http.HttpServletRequest;
7import javax.servlet.http.HttpServletResponse;
8import javax.servlet.http.HttpSession;
9
10import cn.itcast.cd.domain.ShoppingCar;
11
12public class BuyServlet extends HttpServlet {
13	@Override
14	protected void service(HttpServletRequest request, HttpServletResponse response)
15			throws ServletException, IOException {
16		request.setCharacterEncoding("UTF-8");
17		response.setContentType("text/html;charset=utf-8");
18	 //1.  获取请求中的参数.
19		String product = request.getParameter("product");
20		String num	 = request.getParameter("num");
21     //2. 获取到购物车
22		   //2.1  首先要到session中找一下是否已经有了购物车. 如果有的话就不需要创建了... 直接把货品放到购物车中就可以了
23			HttpSession httpSession = request.getSession();
24			ShoppingCar shoppingCar = (ShoppingCar)httpSession.getAttribute("SHOPINGCAR_IN_SESSION");
25			if(shoppingCar==null){ //说明是第一次购物. 还没有购物车的
26				//2.2  如果从session中没有找到购物车. 需要新创建一个购物车并且放到session中.为了下次购物使用这个购物车
27				shoppingCar = new ShoppingCar();
28				httpSession.setAttribute("SHOPINGCAR_IN_SESSION", shoppingCar);
29			}
30			shoppingCar.add(product, Integer.parseInt(num));
31			PrintWriter pw = response.getWriter();
32			pw.println("添加成功<br/>");
33			pw.println("<a href='/buy.html'>继续购物</a><br/>");
34			pw.println("<a href='/list'>管理购物</a><br/>");
35		
36	}
37}
38
39package cn.itcast.cd.servlet;
40
41import java.io.IOException;
42import java.io.PrintWriter;
43
44import javax.servlet.ServletException;
45import javax.servlet.http.HttpServlet;
46import javax.servlet.http.HttpServletRequest;
47import javax.servlet.http.HttpServletResponse;
48import javax.servlet.http.HttpSession;
49
50import cn.itcast.cd.domain.ShoppingCar;
51import cn.itcast.cd.domain.ShoppingCarItem;
52import cn.itcast.cd.domain.User;
53
54public class ListServlet extends HttpServlet {
55	@Override
56	protected void service(HttpServletRequest request, HttpServletResponse response)
57			throws ServletException, IOException {
58		request.setCharacterEncoding("UTF-8");
59		response.setContentType("text/html;charset=utf-8");
60		
61		HttpSession httpSession = request.getSession();
62		//1. 先获取session中的User
63		 User user  = (User) httpSession.getAttribute("USER_IN_SESSION");
64		 PrintWriter pw = response.getWriter();
65		 pw.println("当前用户为:"+user.getUsername()+"<br/>");
66		//2. 获取session的购物车
67		 		ShoppingCar shoppingCar = (ShoppingCar) httpSession.getAttribute("SHOPINGCAR_IN_SESSION");
68		      //2.1  如果在session中购物车的话,列出购物车中的明细
69		 	   if(shoppingCar!=null){
70		 		   for (ShoppingCarItem item : shoppingCar.getList()) {
71		 			   pw.println("货品:"+item.getProduct()+"  数量:"+item.getNum()+"<br/>");
72		 		   }
73		 	   }else{
74		 		   //2.2 在session中没有购物车的话.提示用户没有当前用户名购物车
75		 		    pw.println("当前用户没有购物车.");
76		 	   }
77		
78		
79		
80	}
81}
82
83package cn.itcast.cd.servlet;
84
85import java.io.IOException;
86import java.io.PrintWriter;
87
88import javax.servlet.ServletException;
89import javax.servlet.http.HttpServlet;
90import javax.servlet.http.HttpServletRequest;
91import javax.servlet.http.HttpServletResponse;
92import javax.servlet.http.HttpSession;
93
94import cn.itcast.cd.domain.User;
95
96public class LoginServlet extends HttpServlet {
97
98	@Override
99	protected void service(HttpServletRequest request, HttpServletResponse response)
100			throws ServletException, IOException {
101		request.setCharacterEncoding("UTF-8");
102		response.setContentType("text/html;charset=utf-8");
103		
104		//1. 接收请求中的数据封装对象
105		String username = request.getParameter("username");
106		String password = request.getParameter("password");
107		User user = new User();
108		user.setPassword(password);
109		user.setUsername(username);
110		
111		//2. 将用户方到session中供ListServlet从session中访问到User
112		HttpSession  httpSession = request.getSession();
113		httpSession.setAttribute("USER_IN_SESSION", user);
114		
115		PrintWriter pw = response.getWriter();
116		pw.println("欢迎:"+username+"<br/>");
117		pw.println("<a href='/buy.html'>购物</a><br/>");
118		pw.println("<a href='/list'>管理购物</a><br/>");
119	}
120
121	
122}

用户登录页面：

Html代码 复制代码 收藏代码

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"\>

  2. <html>

  3. <head>

  4. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

  5. <title>用户登录</title>

  6. </head>

  7. <body>

  8. <form action\="/login" method\="post"\>

  9. 用户名：<input type="text" name="username"><br/>

  10. 密码：<input type="text" name="password"><br/>

  11. <input type="submit" value="登录">

  12. </form>

  13. </body>

  14. </html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

1<html>
2<head>
3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
4<title>用户登录</title>
5</head>
6<body>
7
8<form action="/login" method="post">
9	用户名：<input type="text" name="username"><br/>
10	密码：<input type="text" name="password"><br/>
11	<input type="submit" value="登录">
12</form>
13</body>
14</html>

购买页面：

Html代码 复制代码 收藏代码

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"\>

  2. <html>

  3. <head>

  4. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

  5. <title>购物货品</title>

  6. </head>

  7. <body>

  8. <form action\="/buy" method\="post"\>

  9. 货品：<select name="product">

  10. <option value\="鼠标"\>鼠标</option\>
  11. <option value\="键盘"\>键盘</option\>
  12. <option value\="内存"\>内存</option\>
  13. <option value\="显示器"\>显示器</option\>

  14. </select> <br/>

  15. 数量：<input type="text" name="num"><br/>

  16. <input type="submit" value="购买">

  17. </form>

  18. </body>

  19. </html>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

1<html>
2<head>
3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
4<title>购物货品</title>
5</head>
6<body>
7
8<form action="/buy" method="post">
9	货品：<select name="product">
10		<option value="鼠标">鼠标</option>
11		<option value="键盘">键盘</option>
12		<option value="内存">内存</option>
13                  <option value="显示器">显示器</option>
14	</select>  <br/>
15	数量：<input type="text" name="num"><br/>
16	<input type="submit" value="购买">
17</form>
18</body>
19</html>

web.xml配置：

Xml代码 复制代码 收藏代码

  1. <?xml version\="1.0" encoding\="UTF-8"?>

  2. <web-app xmlns="http://java.sun.com/xml/ns/javaee"

  3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  4. xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app\_2\_5.xsd"

  5. version="2.5">

  6. <servlet>

  7. <servlet-name>LoginServlet</servlet-name>

  8. <servlet-class>cn.itcast.cd.servlet.LoginServlet</servlet-class>

  9. </servlet>

  10. <servlet-mapping>

  11. <servlet-name>LoginServlet</servlet-name>

  12. <url-pattern>/login</url-pattern>

  13. </servlet-mapping>

  14. <servlet>

  15. <servlet-name>BuyServlet</servlet-name>

  16. <servlet-class>cn.itcast.cd.servlet.BuyServlet</servlet-class>

  17. </servlet>

  18. <servlet-mapping>

  19. <servlet-name>BuyServlet</servlet-name>

  20. <url-pattern>/buy</url-pattern>

  21. </servlet-mapping>

  22. <servlet>

  23. <servlet-name>ListServlet</servlet-name>

  24. <servlet-class>cn.itcast.cd.servlet.ListServlet</servlet-class>

  25. </servlet>

  26. <servlet-mapping>

  27. <servlet-name>ListServlet</servlet-name>

  28. <url-pattern>/list</url-pattern>

  29. </servlet-mapping>

  30. </web-app>

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