validate（）方法验证
一个ACTION类继承ActionSupport有何用处？
答：在ActionSupport中实现了很
多接口，就拿一个来讲，validate()方法，是默认的验证。我们可以在我们的action类中重写一下此方法。比方说验证用户名是否为空。这个方法
不需要调用，当S：FORM表单提交了，到了action类中会首先执行此方法。对数据进行验证。
用 el 表达式 或 struts 标签 读取错误信息
1 <%@ page language="java" contentType="text/html; charset=ISO-8859-1"
2 pageEncoding="ISO-8859-1"%>
3 <%@ taglib uri="/struts-tags" prefix="s"%>
4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5 <html>
6 <head>
7 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
8 <title>Insert title here</title>
9 <style>
10 span{
11 color:red;; //css
12 }
13
14
15 </style>
16 </head>
17 <body>
18 <form action="login" method="post">
19 username:<input type="text" name="username" /><span> ${errors.username[0] }|<s:property value="errors.username[0]"/></span><br /> <br />
20 password:<input type="password" name="password" /><span>${errors.password[0] }|<s:property value="errors.password[0]"/></span><br /><br />
21 <input type="submit" value="submit" /> <input type="reset" value="cancel" />
23 </form>
24 </body>
25 </html>
validate()方法校验
1 package com.helen.action;
2
3 import com.opensymphony.xwork2.ActionSupport;
4
5 public class LoginAction extends ActionSupport {
6 private String username;
7 private String password;
8
9 public void validate() {
10
11 if (username == null || username.equals("")) {
12 this.addFieldError("username", "please enter your username!");
13 } else if (!username.equals("admin")) {
14 this.addFieldError("username", "username is not right!");
15 }
16 if (password == null || password.equals("")) {
17
18 this.addFieldError("password", "please enter your password!");
19 } else if (!password.equals("123")) {
20 this.addFieldError("password", "password is not right!");
21 }
22
23 }
24
25 public String getUsername() {
26 return username;
27 }
28
29 public void setUsername(String username) {
30 this.username = username;
31 }
32
33 public String getPassword() {
34 return password;
35 }
36
37 public void setPassword(String password) {
38 this.password = password;
39 }
40
41 }
返回值为 input
<action name="login" class="com.helen.action.LoginAction">
<result name="input">/index.jsp</result>
<result>/success.jsp</result>
</action>
时间： 2024-08-03 15:47:22