struts2使用模型传值

用户bean

package userBeans;

public class User {
    private String username;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Override
    public String toString() {
        return "User [username=" + username + "]";
    }



}

action

package Actions;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

import userBeans.User;

public class loginAction extends ActionSupport implements ModelDriven<User>{
    private User user =new User();

    @Override
    public String execute() throws Exception {
        return Action.SUCCESS;
    }

    @Override
    public User getModel() {
        // TODO Auto-generated method stub
        return user;
    }

    @Override
    public void validate() {
        //在沒有使用beans的情況下 可以用null 来进行比较
        if (user.getUsername().equals("")) {
            addFieldError("username", "用户名不能为空");
        }
    }


}

struts 中需要注意

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
        "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
    <constant name="struts.i18n.encoding" value="GBK" />
    <package name="default" extends="struts-default">
    <action name="userAction" class="Actions.loginAction">
            <result name="success">/result.jsp</result>
            //这里的name 为input 在vaildada执行错误时执行该//代码  不写将不会正确
            <result name="input">/index.jsp</result>
        </action>

    </package>
</struts>

其他代码

<%@ page language="Java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>??</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
    <s:fielderror />
    <form action="userAction" method="post">
        <s:textfield name="username" label="验证信息"></s:textfield>
        <s:submit value="验证"></s:submit>
    </form>
</body>
</html>

<%@ page language="Java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="s" uri="/struts-tags"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">    
    <title>??</title>        
  <meta http-equiv="pragma" content="no-cache">
  <meta http-equiv="cache-control" content="no-cache">
  <meta http-equiv="expires" content="0">    
  <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
  <meta http-equiv="description" content="This is my page">
 </head>
 <body>
 <s:property value="username"/>
 </body>
</html>

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <display-name>strutsDemo</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
    <filter>

        <filter-name>struts2</filter-name>

        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>struts2</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>
</web-app>

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原文地址：https://www.cnblogs.com/dgwblog/p/7635215.html