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。

<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

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

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

<body>
username:${user.username}<br>
password:${user.password}<br>
age:${user.age}<br>
birthday:${user.birthday}<br>
graduate:${user.graduate}<br>
</body>

<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

<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"%>）

<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

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

<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。

巴特西

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

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