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 <body> <h1>用户注册</h1> <form action="RegisterServlet" method="post"> username:<input type="text" name="username"><br> password:<input type="password" name="password"><br> repassword:<input type="password" name="repassword"><br> age:<input type="text" name="age"><br> birthday:<input type="text" name="birthday"><br> graduate:<input type="text" name="graduate"><br> <input type="submit" value="submit"> </form> </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 private String username; private String password; private String repassword; private int age; private Date birthday; private Date graduate; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getRepassword() { return repassword; } public void setRepassword(String repassword) { this.repassword = repassword; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public Date getGraduate() { return graduate; } public void setGraduate(Date graduate) { this.graduate = graduate; }
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 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //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 String username=request.getParameter("username"); String password=request.getParameter("password"); String repassword=request.getParameter("repassword"); int age=Integer.valueOf(request.getParameter("age")); String birthday=request.getParameter("birthday"); String graduate=request.getParameter("graduate"); Date graduate1=null; Date birthday1=null; Map<String, String> errors = new HashMap<String, String>(); if (username == null) { errors.put("username", "用户名不能为空"); } else { if (username.length()<4||username.length()>6) { errors.put("username", "用户名必须是4到6位"); } } if (password == null) { errors.put("password", "密码不能为空"); } else { if (password.length()<4||password.length()>6) { errors.put("password", "密码必须是4-6位数字"); } } if (repassword ==null) { errors.put("repassword", "确认密码不能为空"); } else { if (!(password.equals(repassword))) { errors.put("repassword", "确认密码必须与密码输入一致"); } } if(age>50||age<10) { errors.put("age", "年龄无效"); } if(birthday!=null) { DateFormat df=new SimpleDateFormat("yyyy-MM-dd"); try{ birthday1=df.parse(birthday); }catch(Exception e) { errors.put("birthday", "日期格式不正确"); } }else{ errors.put("birthday", "生日不能为空"); } if(graduate!=null) { DateFormat df=new SimpleDateFormat("yyyy-MM-dd"); try{ graduate1=df.parse(graduate); }catch(Exception e) { errors.put("graduate", "日期格式不正确"); } }else{ errors.put("graduate", "毕业日期不能为空"); } if(null!=graduate1&&null!=birthday1) { Calendar c1=Calendar.getInstance(); c1.setTime(birthday1); Calendar c2=Calendar.getInstance(); c2.setTime(graduate1); if(!c1.before(c2)) { errors.put("graduate", "毕业日期出生日期不匹配"); } } <span style="color:#FF0000;">if(errors.size()==0) { User user=new User(); user.setUsername(username); user.setAge(age); user.setPassword(password); user.setRepassword(repassword); user.setBirthday(birthday1); user.setGraduate(graduate1); request.setAttribute("user", user); request.getRequestDispatcher("result.jsp").forward(request, response); }else { request.setAttribute("errors", errors); request.setAttribute("username", username); request.setAttribute("password",password); request.setAttribute("birthday", birthday); request.setAttribute("graduate",graduate); request.setAttribute("age",age); request.getRequestDispatcher("register.jsp").forward(request, response); }</span> }
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 <body> username:${user.username}<br> password:${user.password}<br> age:${user.age}<br> birthday:${user.birthday}<br> graduate:${user.graduate}<br> </body>
register.jsp修改后内容
[html] view plain copy <body> <h1>用户注册</h1> <form action="RegisterServlet" method="post"> username:<input type="text" name="username" value="${username}">${errors.username}<br> password:<input type="password" name="password">${errors.password}<br> repassword:<input type="password" name="repassword">${errors.repassword}<br> age:<input type="text" name="age" value="${age}">${errors.age}<br> birthday:<input type="text" name="birthday" value="${birthday}">${errors.birthday}<br> graduate:<input type="text" name="graduate" value="${graduate}">${errors.graduate}<br> <input type="submit" value="submit"> </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 <servlet> <description></description> <display-name>ReigsterServlet</display-name> <servlet-name>ReigsterServlet</servlet-name> <servlet-class>ReigsterServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ReigsterServlet</servlet-name> <url-pattern>/RegisterServlet</url-pattern> </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 <s:form action="register.action" theme="simple"><br> username:<s:textfield name="username" label="username"></s:textfield><br> password:<s:password name="password" label="password"></s:password><br> repassword:<s:password name="repassword" lable="repassword"></s:password><br> age:<s:textfield name="age" label="age"></s:textfield><br> birthday:<s:textfield name="birthday" label="birthday"></s:textfield><br> graduate:<s:textfield name="graduate" label="age"></s:textfield><br> <s:submit value="submit"></s:submit> </s:form>
3）接下来我们编写RegisterAction类
[java] view plain copy public class RegisterAction extends ActionSupport { private String username; private String password; private String repassword; private int age; private Date birthday; private Date graduate; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getRepassword() { return repassword; } public void setRepassword(String repassword) { this.repassword = repassword; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public Date getGraduate() { return graduate; } public void setGraduate(Date graduate) { this.graduate = graduate; } @Override public String execute() throws Exception { // TODO Auto-generated method stub System.out.println("execute()"); return SUCCESS; } @Override public void validate() { // TODO Auto-generated method stub System.out.println("validate()"); if(null==username||username.length()<4||username.length()>6) { this.addFieldError("username","用户名无效"); } if(null==password||password.length()<4||password.length()>6) { this.addFieldError("password","密码无效"); }else if(null==repassword||repassword.length()!=password.length()) { this.addFieldError("repassword","密码长度不一致"); }else if(!repassword.equals(password)) { this.addFieldError("repassword","密码不一致"); } if(age<10||age>50) { this.addFieldError("age","年龄无效"); } if(null==birthday) { this.addFieldError("birthday","出生日期为空"); } if(null==graduate) { this.addFieldError("graduate","毕业日期为空"); } if(null!=graduate&&null!=birthday) { Calendar c1=Calendar.getInstance(); c1.setTime(birthday); Calendar c2=Calendar.getInstance(); c2.setTime(graduate); if(!c1.before(c2)) { this.addFieldError("graduate","毕业日期出生日期不匹配"); } } } }
4）配置struts.xml文件
[html] view plain copy <action name="register" class="cn.sict.register.RegisterAction"> <result name="success">/result.jsp</result>//正确就跳转到result.jsp <result name="input">/register.jsp</result>//错误就跳转到register.jsp </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。
转载于:https://www.cnblogs.com/jay36/p/7515674.html
