从一个简单的小实例分析JSP+Servelt与JSP+Struts2框架的区别

从一个简单的小实例分析JSP+Servelt与JSP+Struts2框架的区别
最近在学struts2，struts2相比以前的JSP+Servlet，在处理流程上的更简单，我们就一个小实例来具体分析一下。

实例内容如下：

实现一个简单的注册页面包括：用户名、密码、重复密码、年龄、出生日期、毕业日期

要求如下：
用户名的长度在4-6之间
密码的长度在4-6之间
重复密码与密码相等
年龄在10-50之间
出生日期在毕业日期之前

输入错误返回原页面，并在原页面的文本框后面显示具体的错误信息。正确输入则跳入下个页面将信息显示出来。

1、JSP+Servlet

1）我们编写注册页面register.jsp

注册页面，不使用struts标签库的话，基本上大同小异，唯一的区别在form中action选项上，这里面的servlet自然要跳到RegisterServlet上进行相应的信息处理。我们先各自处理，然后再来比较吧。
[html] view plain copy
1. <body>
2. <h1>用户注册</h1>
3. <form action="RegisterServlet" method="post">
4. username:<input type="text" name="username"><br>
5. password:<input type="password" name="password"><br>
6. repassword:<input type="password" name="repassword"><br>
7. age:<input type="text" name="age"><br>
8. birthday:<input type="text" name="birthday"><br>
9. graduate:<input type="text" name="graduate"><br>
10. <input type="submit" value="submit">
11. </form>
12. </body>
2）因为这些属性都是属于注册用户的，我们再构建一个User类
[java] view plain copy
1. private String username;
2. private String password;
3. private String repassword;
4. private int age;
5. private Date birthday;
6. private Date graduate;
7. public String getUsername() {
8. return username;
9. }
10. public void setUsername(String username) {
11. this.username = username;
12. }
13. public String getPassword() {
14. return password;
15. }
16. public void setPassword(String password) {
17. this.password = password;
18. }
19. public String getRepassword() {
20. return repassword;
21. }
22. public void setRepassword(String repassword) {
23. this.repassword = repassword;
24. }
25. public int getAge() {
26. return age;
27. }
28. public void setAge(int age) {
29. this.age = age;
30. }
31. public Date getBirthday() {
32. return birthday;
33. }
34. public void setBirthday(Date birthday) {
35. this.birthday = birthday;
36. }
37. public Date getGraduate() {
38. return graduate;
39. }
40. public void setGraduate(Date graduate) {
41. this.graduate = graduate;
42. }
3）输入效验可以分为客户端效验和服务器端的效验，客户端的效验是将验证代码用javascript写到页面中，这里面我们统一用服务器端效验。编写RegisterServlet
[java] view plain copy
1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
2. // TODO Auto-generated method stub
3. //从页面传过来的数据都是字符形式的，我们要进行相应的转换
4. String username=request.getParameter("username");
5. String password=request.getParameter("password");
6. String repassword=request.getParameter("repassword");
7. int age=Integer.valueOf(request.getParameter("age"));
8. String birthday=request.getParameter("birthday");
9. String graduate=request.getParameter("graduate");
10. Date graduate1=null;
11. Date birthday1=null;
12. Map<String, String> errors = new HashMap<String, String>();
13. if (username == null)
14. {
15. errors.put("username", "用户名不能为空");
16. } else
17. {
18. if (username.length()<4||username.length()>6)
19. {
20. errors.put("username", "用户名必须是4到6位");
21. }
22. }
23. if (password == null)
24. {
25. errors.put("password", "密码不能为空");
26. } else
27. {
28. if (password.length()<4||password.length()>6)
29. {
31. errors.put("password", "密码必须是4-6位数字");
32. }
33. }
34. if (repassword ==null)
35. {
36. errors.put("repassword", "确认密码不能为空");
37. } else
38. {
39. if (!(password.equals(repassword)))
40. {
41. errors.put("repassword", "确认密码必须与密码输入一致");
42. }
43. }
44. if(age>50||age<10)
45. {
46. errors.put("age", "年龄无效");
47. }
48. if(birthday!=null)
49. {
50. DateFormat df=new SimpleDateFormat("yyyy-MM-dd");
52. try{
53. birthday1=df.parse(birthday);
54. }catch(Exception e)
55. {
56. errors.put("birthday", "日期格式不正确");
57. }
58. }else{
59. errors.put("birthday", "生日不能为空");
60. }
61. if(graduate!=null)
62. {
63. DateFormat df=new SimpleDateFormat("yyyy-MM-dd");
65. try{
66. graduate1=df.parse(graduate);
67. }catch(Exception e)
68. {
69. errors.put("graduate", "日期格式不正确");
70. }
71. }else{
72. errors.put("graduate", "毕业日期不能为空");
73. }
74. if(null!=graduate1&&null!=birthday1)
75. {
76. Calendar c1=Calendar.getInstance();
77. c1.setTime(birthday1);
78. Calendar c2=Calendar.getInstance();
79. c2.setTime(graduate1);
80. if(!c1.before(c2))
81. {
82. errors.put("graduate", "毕业日期出生日期不匹配");
83. }
84. }
85. <span style="color:#FF0000;">if(errors.size()==0)
86. {
87. User user=new User();
88. user.setUsername(username);
89. user.setAge(age);
90. user.setPassword(password);
91. user.setRepassword(repassword);
92. user.setBirthday(birthday1);
93. user.setGraduate(graduate1);
94. request.setAttribute("user", user);
95. request.getRequestDispatcher("result.jsp").forward(request, response);
96. }else
97. {
98. request.setAttribute("errors", errors);
99. request.setAttribute("username", username);
100. request.setAttribute("password",password);
101. request.setAttribute("birthday", birthday);
102. request.setAttribute("graduate",graduate);
103. request.setAttribute("age",age);
104. request.getRequestDispatcher("register.jsp").forward(request, response);
106. }</span>
108. }
4)然后我们编写一下result.jsp结果页面和修改一下register.jsp页面（出现错误后跳转，显示相应的错误信息）

result.jsp页面
[html] view plain copy
1. <body>
2. username:${user.username}<br>
3. password:${user.password}<br>
4. age:${user.age}<br>
5. birthday:${user.birthday}<br>
6. graduate:${user.graduate}<br>
7. </body>
register.jsp修改后内容
[html] view plain copy
1. <body>
2. <h1>用户注册</h1>
3. <form action="RegisterServlet" method="post">
4. username:<input type="text" name="username" value="${username}">${errors.username}<br>
5. password:<input type="password" name="password">${errors.password}<br>
6. repassword:<input type="password" name="repassword">${errors.repassword}<br>
7. age:<input type="text" name="age" value="${age}">${errors.age}<br>
8. birthday:<input type="text" name="birthday" value="${birthday}">${errors.birthday}<br>
9. graduate:<input type="text" name="graduate" value="${graduate}">${errors.graduate}<br>
10. <input type="submit" value="submit">
11. </form>
5)最后我们查看一下web.xml文件中，zai生成RegisterServlet时是否有相关的配置
[html] view plain copy
1. <servlet>
2. <description></description>
3. <display-name>ReigsterServlet</display-name>
4. <servlet-name>ReigsterServlet</servlet-name>
5. <servlet-class>ReigsterServlet</servlet-class>
6. </servlet>
7. <servlet-mapping>
8. <servlet-name>ReigsterServlet</servlet-name>
9. <url-pattern>/RegisterServlet</url-pattern>
10. </servlet-mapping>
Ok，到这上面描述的Jsp+Servlet的基本功能都已实现，RegisterServlet作为整个代码的核心，写的是很长的。其实我们可以优化一下，将判断的内容放在formbean类中，然后在servlet中判调用。但是代码量是不减的，只能是让逻辑业务更清晰。

2、用Struts框架来实现以上功能。

1）首先struts的基本配置省略，可以参考http://blog.csdn.net/fumier/article/details/44626461

2）编写register.jsp页面，这里面使用了struts标签库，需要在开头第二行加入（ <%@ taglib prefix="s" uri="/struts-tags"%>）
[html] view plain copy
1. <s:form action="register.action" theme="simple"><br>
2. username:<s:textfield name="username" label="username"></s:textfield><br>
3. password:<s:password name="password" label="password"></s:password><br>
4. repassword:<s:password name="repassword" lable="repassword"></s:password><br>
5. age:<s:textfield name="age" label="age"></s:textfield><br>
6. birthday:<s:textfield name="birthday" label="birthday"></s:textfield><br>
7. graduate:<s:textfield name="graduate" label="age"></s:textfield><br>
8. <s:submit value="submit"></s:submit>
9. </s:form>
3）接下来我们编写RegisterAction类
[java] view plain copy
1. public class RegisterAction extends ActionSupport {
2. private String username;
3. private String password;
4. private String repassword;
5. private int age;
6. private Date birthday;
7. private Date graduate;
9. public String getUsername() {
10. return username;
11. }
13. public void setUsername(String username) {
14. this.username = username;
15. }
17. public String getPassword() {
18. return password;
19. }
21. public void setPassword(String password) {
22. this.password = password;
23. }
25. public String getRepassword() {
26. return repassword;
27. }
29. public void setRepassword(String repassword) {
30. this.repassword = repassword;
31. }
33. public int getAge() {
34. return age;
35. }
37. public void setAge(int age) {
38. this.age = age;
39. }
41. public Date getBirthday() {
42. return birthday;
43. }
45. public void setBirthday(Date birthday) {
46. this.birthday = birthday;
47. }
49. public Date getGraduate() {
50. return graduate;
51. }
53. public void setGraduate(Date graduate) {
54. this.graduate = graduate;
55. }
57. @Override
58. public String execute() throws Exception {
59. // TODO Auto-generated method stub
60. System.out.println("execute()");
61. return SUCCESS;
62. }
63. @Override
64. public void validate() {
65. // TODO Auto-generated method stub
66. System.out.println("validate()");
67. if(null==username||username.length()<4||username.length()>6)
68. {
69. this.addFieldError("username","用户名无效");
70. }
71. if(null==password||password.length()<4||password.length()>6)
72. {
73. this.addFieldError("password","密码无效");
74. }else if(null==repassword||repassword.length()!=password.length())
75. {
76. this.addFieldError("repassword","密码长度不一致");
77. }else if(!repassword.equals(password))
78. {
79. this.addFieldError("repassword","密码不一致");
80. }
81. if(age<10||age>50)
82. {
83. this.addFieldError("age","年龄无效");
84. }
85. if(null==birthday)
86. {
87. this.addFieldError("birthday","出生日期为空");
88. }
89. if(null==graduate)
90. {
91. this.addFieldError("graduate","毕业日期为空");
92. }
93. if(null!=graduate&&null!=birthday)
94. {
95. Calendar c1=Calendar.getInstance();
96. c1.setTime(birthday);
97. Calendar c2=Calendar.getInstance();
98. c2.setTime(graduate);
99. if(!c1.before(c2))
100. {
101. this.addFieldError("graduate","毕业日期出生日期不匹配");
102. }
103. }
104. }
105. }
4）配置struts.xml文件
[html] view plain copy
1. <action name="register" class="cn.sict.register.RegisterAction">
2. <result name="success">/result.jsp</result>//正确就跳转到result.jsp
3. <result name="input">/register.jsp</result>//错误就跳转到register.jsp
4. </action>
5）result.jsp与1中的相同，至此，就完成了所有的功能。

接下来，我们来看一下，使用struts框架，我们省略了哪些工作。

1）首先没有set/get方法了。

2）没有了servlet中从页面获得字符，然后再转换为需要的类型，然后简单的配置相应的result参数，就可以跳转到相应的页面。

3）继承了ActionSupport类重写validate（）方法，使逻辑清晰。

Struts对上述的操作进行了包装，提高了程序的课重用性，我们只需要修改少量的参数和配置文件，就可以达到想要的效果。
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原文地址：https://www.cnblogs.com/jay36/p/7515674.html