Struts 学习笔记2(输入校验、国际化、异常处理)

项目文件结构

项目源文件下载地址：http://dl.dbank.com/c05qyg3yir

Struts2的输入校验

Struts2输入校验、执行流程：

1）首先进行类型转换

2）然后进行输入校验（执行validate方法）

3）如果在上述过程中出现了任何错误，都不会再去执行 execute方法，会转向 struts.xml 中该 action 的名为 input 的 result 所对应的页面。

要点：

1. ActionSupport 类的 addActionError()方法的实现：首先创建一个ArrayList对象，然后将错误消息添加到该 ArrayList对象中。

2. 当调用 getActionErrors()方法返回 Action 级别的错误信息列表时，返回的实际上是集合的一个副本而不是集合本身，因此对集合副本调用 clear()方法清除的依旧是副本中的元素而非原集合中的元素，此时原集合中的内容没有收到任何的影响。换句话说，Action级别的错误信息列表对开发者来说是只读的。

3. Field Error 级别的错误信息底层是用 LinkedHashMap 实现的，该Map 的 key 是 String 类型，value 是 List<String>类型，这就表示一个 Field Name 可以对应多条错误信息，这些错误信息都放置在List<String>集合当中。

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ taglib prefix="s" uri="/struts-tags" %>

………………………………

<body>

<s:actionerror cssStyle="color:red"/>

----------------------------------------

<s:fielderror cssStyle="color:blue"></s:fielderror>

<!--

username: <input type="text" name="username" size="20"><br>

password: <input type="password" name="password" size="20"><br>

repassword: <input type="password" name="repassword" size="20"><br>

age: <input type="text" name="age" size="20"><br>

birthday: <input type="text" name="birthday" size="20"><br>

graduation: <input type="text" name="graduation" size="20"><br>

</form>

-->

<s:form action="register.action" theme="simple"><!—-加theme="simple修饰以简单表单呈现-->

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" label="repassword"></s:password><br>

age: <s:textfield name="age" label="age"></s:textfield><br>

birthday: <s:textfield name="birthday" label="birthday"></s:textfield><br>

graduation: <s:textfield name="graduation" label="graduation"></s:textfield><br>

<s:submit value="submit"></s:submit>

</s:form>

</body>

</html>

RegisterAction.java

package com.shengsiyuan.struts2;

import java.util.Calendar;

import java.util.Date;

import com.opensymphony.xwork2.ActionSupport;

public class RegisterAction extends ActionSupport

{

private String username;

private String password;

private String repassword;

private int age;

private Date birthday;

private Date graduation;

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 getGraduation()

{

return graduation;

}

public void setGraduation(Date graduation)

{

this.graduation = graduation;

}

@Override

public String execute() throws Exception

{

return SUCCESS;

}

@Override

public void validate()

{

if(null == username || username.length() < 4 || username.length() > 6)

{

this.addActionError("username invalid"); //Action级别的错误

this.addFieldError("username", "username invalid in field");//field级别的错误

}

if(null == password || password.length() < 4 || password.length() > 6)

{

this.addActionError("password invalid");

}

else if(null == repassword || repassword.length() < 4 || repassword.length() > 6)

{

this.addActionError("repassword invalid");

}

else if(!password.equals(repassword))

{

this.addActionError("the passwords not the same");

}

if(age < 10 || age > 50)

{

this.addActionError("age invalid");

}

if(null == birthday)

{

this.addActionError("birthday invalid");

}

if(null == graduation)

{

this.addActionError("graduation invalid");

}

if(null != birthday && null != graduation)

{

Calendar c1 = Calendar.getInstance(); //获取日期

c1.setTime(birthday);

Calendar c2 = Calendar.getInstance();

c2.setTime(graduation);

if(!c1.before(c2)) //如果c1不在c2前

{

this.addActionError("birthday should be before graduation");

}

//this.getFieldErrors().clear(); //clear()方法清空的只是副本

//this.getActionErrors().clear();

//this.clearActionErrors(); //清除Action级别的错误消息

//this.clearFieldErrors(); //清除field级别的错误消息

System.out.println("invoked!!!");

}

struts.xml

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

<!DOCTYPE struts PUBLIC

"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

"http://struts.apache.org/dtds/struts-2.0.dtd">

<result name="success">/result.jsp</result>

</action>

<result name="success">/output.jsp</result>

</action>

<result name="success">/output.jsp</result>

</action>

<action name="register" class="com.shengsiyuan.struts2.RegisterAction">

<result name="success">/registerResult.jsp</result>

<result name="input">/register.jsp</result>

</action>

</package>

</struts>

截图

提交之前截图

以html标签提交之后的截图

以struts标签，且未加theme="simple"属性提交的结果

若使用<s:form action="register.action" theme="simple">则呈现的结果同以html提交一样。不管是Action级别的，还是field级别的，在执行excute方法时，只要对应的错误容器中有错误消息，则转到input对应的页面，如果容器中没有错误消息，则继续往下执行。