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  • Struts2学习（三）

    获取页面数据

    1、属性驱动

    • 对于属性驱动，我们需要在Action中定义与表单元素对应的所有的属性，因而在Action中会出现很多的getter和setter方法
    • 表单 或 URL 中的 参数名称 跟 Action 类中的属性名称一致，即可
    • 属性驱动的第一种方式（推荐使用的方式，直接将action做一个model(类似bean结构),就可以得到请求参数.）

      index.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Apache Struts</title>
<style type="text/css">
    .container { width: 90% ; margin: 10px auto ; box-shadow: 0px 0px 5px 4px #dedede ; padding: 5px 5px ; }
    ul .required { color : blue ; }
    ul li { font-size: 16px ; padding: 5px 5px ;  }
</style>
</head>
<body>
 　　<div class="container">
       <h4>属性驱动(赞成使用):</h4>
       <form action="${ pageContext.request.contextPath }/customer/results/register" method="post" >
                <input type="text" name="username" placeholder="用户名">
                <input type="password" name="password" placeholder="密码">
                <input type="password" name="confirm" placeholder="确认密码">
                <input type="submit" value="注册">
        </form>
        <a href="${ pageContext.request.contextPath }/customer/results/register?username=zhangsanfeng">注册</a>
    </div>

</body>
</html>

      struts.xml

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

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
    "http://struts.apache.org/dtds/struts-2.5.dtd">

<struts>
     <package name="customer-results" namespace="/customer/results" extends="struts-default">

        <action name="register" class="ecut.results.action.RegisterAction">
            <result>/WEB-INF/pages/results/register_success.jsp</result>
        </action>

        <action name="login" class="ecut.results.action.LoginAction">
            <result>/WEB-INF/pages/results/login_success.jsp</result>
        </action>

    </package>
</struts>

      Action类

      package ecut.results.action;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import com.opensymphony.xwork2.Action;

import ecut.results.entity.Customer;

public class RegisterAction implements Action {
    
    private static final Logger logger = LogManager.getLogger();
    
    private String username ;
    private String password ;
    private String confirm ;
    
    private Customer customer ;

    @Override
    public String execute() throws Exception {
        
        if( customer != null ) {
            logger.info( "customer username : " + customer.getUsername() );
            logger.info( "customer password : " + customer.getPassword() );
            logger.info( "customer confirm : " + customer.getConfirm() );
        } else {
            logger.info( "username : " + username );
            logger.info( "password : " + password );
            logger.info( "confirm : " + confirm );
        }
        
        return SUCCESS;
    }

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }
    

    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 getConfirm() {
        return confirm;
    }

    public void setConfirm(String confirm) {
        this.confirm = confirm;
    }
    
}

      register_success.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>注册成功</title>
</head>
<body>

    <h1>注册成功</h1>
    
    <h4> username: ${ username } </h4>
    
    <h4> page scope: ${ pageScope.username } </h4>
    
    <h4> request scope: ${ requestScope.username } </h4>
    
    <h4> session scope: ${ sessionScope.username } </h4>
    
    <h4> application scope: ${ applicationScope.username } </h4>
    
    <hr>
    
    <h4> customer.username : ${ customer.username } </h4>
    
    <h4> request scope: ${ requestScope.customer.username } </h4>

</body>
</html>

      在同一个请求中因此参数保留在requestScope中

    • 属性驱动的第二种方式（反对使用，在action中声明一个model，js不通用）

      index.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Apache Struts</title>
<style type="text/css">
    .container { width: 90% ; margin: 10px auto ; box-shadow: 0px 0px 5px 4px #dedede ; padding: 5px 5px ; }
    ul .required { color : blue ; }
    ul li { font-size: 16px ; padding: 5px 5px ;  }
</style>
</head>
<body>
 　　<div class="container">
       <h4>属性驱动(反对使用):</h4>
       <form action="${ pageContext.request.contextPath }/customer/results/register" method="post" >
                <input type="text" name="customer.username" placeholder="用户名">
                <input type="password" name="customer.password" placeholder="密码">
                <input type="password" name="customer.confirm" placeholder="确认密码">
                <input type="submit" value="注册">
        </form>
    </div>

</body>
</html>

      Action中增加customer 的model

    2、模块驱动

    •  对于模型驱动，使用的Action对象需要实现ModelDriven接口并给定所需要的类型.而在Action中我们只需要定义一个封装所有数据信息的javabean
    • 模块驱动的具体实现

      index.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Apache Struts</title>
<style type="text/css">
    .container { width: 90% ; margin: 10px auto ; box-shadow: 0px 0px 5px 4px #dedede ; padding: 5px 5px ; }
    ul .required { color : blue ; }
    ul li { font-size: 16px ; padding: 5px 5px ;  }
</style>
</head>
<body>
　　<div class="container">
       <h4>模型驱动:</h4>
       <form action="${ pageContext.request.contextPath }/customer/results/login" method="post" >
                <input type="text" name="username" placeholder="用户名">
                <input type="password" name="password" placeholder="密码">
                <input type="submit" value="登录">
        </form>
    </div>

</body>
</html>

      Action类

      package ecut.results.action;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ModelDriven;
import ecut.results.entity.Customer;

public class LoginAction implements Action , ModelDriven<Customer> {
    
    private static final Logger logger = LogManager.getLogger();
    
    private Customer customer ;

    @Override
    public String execute() throws Exception {
        System.out.println( this );
        logger.info( "username : " + customer.getUsername() );
        logger.info( "password : " + customer.getPassword() );
        return SUCCESS;
    }
    
    @Override
    public Customer getModel() {
        logger.info( "调用 getModel方法" );
        //首先实现接口ModelDriven，其次通过getModel方法告诉Struts将参数封装到那个对象去
        if( this.customer == null ) {
            logger.info( "创建对象" );
            this.customer = new Customer();
        } 
        return  this.customer ;
    }

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }

}

      Action类实现ModelDriven接口并覆盖getModel()方法，在Action类中实例化一个model对象，由Struts2提供的拦截器（ParametersInterceptor）去完成数据封装，让getModel方法返回这个对象。getModel()方法在excute()方法执行之前。因为每一次请求，都是一个新的action，所以getModel()方法中的判断语句是多余的，与spring有所不同。

      注意：getModel 返回的是Action类中定义的model（this.customer），而不能直接返回 new Customer，excute方法和getModel应该使用的是同一个对象，不然会抛出空指针异常

      login_success.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录成功</title>
</head>
<body>

    <h1>登录成功</h1>
        
    <h4> customer.username : ${ customer.username } </h4>
    
    <h4> request scope: ${ requestScope.customer.username } </h4>
    
    <hr>
    
    <h4> session scope: ${ sessionScope.customer.username } </h4>
    
</body>
</html>

    访问 Servlet API

    1、间接访问（推荐使用的方法）
    • 通过ActionContext来访问
    　　　　ActionContext context = ActionContext.getContext();
    　　　　Map<String,Object> applicationMap = context.getApplication(); // 这个 Map 集合 ServletCotnext
    　　　　Map<String,Object> sessionMap = context.getSession(); // 这个 Map 集合与 HttpSession
    　　　　HttpParameters params = context.getParameters(); // request parameter
    • 测试案例

      index.jsp 

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Apache Struts</title>
<style type="text/css">
    .container { width: 90% ; margin: 10px auto ; box-shadow: 0px 0px 5px 4px #dedede ; padding: 5px 5px ; }
    ul .required { color : blue ; }
    ul li { font-size: 16px ; padding: 5px 5px ;  }
</style>
</head>
<body>
<div class="container">
       <h4>登录( 并将用户信息存储到 Session 中 ):</h4>
       <form action="${ pageContext.request.contextPath }/servlet/login" method="post" >
                <input type="text" name="username" placeholder="用户名">
                <input type="password" name="password" placeholder="密码">
                <input type="submit" value="登录">
        </form>
        <!-- 提示完应该将session中的值移除 ，提示完再次访问不应该再由提示-->
        ${ sessionScope.error_message }
        <%--EL3.0才支持直接调用方法
               ${ pageContext.session.removeAttribute( 'error_message' ) }      
        --%>
        <!-- 使用jsp内置对象删除-->
        <% session.removeAttribute( "error_message" ) ;%> 
    </div>
</body>
</html>

       struts.xml

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

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
    "http://struts.apache.org/dtds/struts-2.5.dtd">

<struts>
　　<package name="servlet" namespace="/servlet" extends="struts-default">

        <default-class-ref class="ecut.results.action.CustomerAction" />

        <action name="login" method="login">
            <!-- 使用了重定向，因此不是同一个request，则通过requestScop是无法获得值的，只能通过session获取 -->
            <result name="success" type="redirectAction">
                <param name="actionName">main</param>
            </result>
            <result name="input" type="redirect">/results/index.jsp</result>
        </action>

        <action name="main">
            <result>/WEB-INF/pages/results/login_success.jsp</result>
        </action>

        <action name="logout" method="logout">
            <!-- 指定重定向到那个页面，工程名可以省略，若不加/则默认是/servlet -->
            <result type="redirect">
                <param name="location">/results/index.jsp</param>
            </result>
        </action>

    </package>
</struts>

      Action类

      package ecut.results.action;

import java.util.Map;

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

import ecut.results.entity.Customer;

public class CustomerAction implements Action , ModelDriven<Customer>{
    
    private Customer customer ;

    @Override
    public String execute() throws Exception {
        System.out.println( "execute" );
        return SUCCESS;
    }
    
    public String login() throws Exception {
        System.out.println( "login" );
        // 获得 当前正在执行的 Action 的 上下文对象
        ActionContext context = ActionContext.getContext();
        // 通过 ActionContext 的 getSession 来获得 与 HttpSession 对应的 Map 集合
        // 针对这个 Map 的 所有操作 都会立即 "同步" 到 HttpSession 对象中
        Map< String , Object > sessionMap = context.getSession();
        if( "zhangsanfeng".equals( customer.getUsername() ) && "hello2017".equals( customer.getPassword() ) ){
            sessionMap.put( "customer" ,  this.customer ) ; // 由拦截器去完成这个操作session.setAttribute( "customer" , this.customer );
            return SUCCESS;
        } else {
            sessionMap.put( "error_message" ,  "用户名或密码错误" );
            return  INPUT;
        }
        
    }
    
    public String logout() throws Exception {
        System.out.println( "logout" );
        ActionContext context = ActionContext.getContext();
        Map< String , Object > sessionMap = context.getSession();
        sessionMap.remove( "customer" ) ; // session.removeAttribute( "customer" );
        return SUCCESS;
    }

    @Override
    public Customer getModel() {
        if( this.customer == null ){
            this.customer = new Customer();
        }
        return this.customer;
    }

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }
    
}

      login_success.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录成功</title>
</head>
<body>

    <h1>登录成功</h1>
        
    <h4> customer.username : ${ customer.username } </h4>
    
    <h4> request scope: ${ requestScope.customer.username } </h4>
    
    <hr>
    
    <h4> session scope: ${ sessionScope.customer.username } </h4>
    
    <a href="${ pageContext.request.contextPath }/servlet/logout">注销</a>

</body>
</html>

      logout_success.jsp

      <%@ page language = "java" pageEncoding = "UTF-8" %>
      <%@ page contentType = "text/html; charset= UTF-8"%>      
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>注销成功</title>
</head>
<body>

    <h1>注销成功</h1>

</body>
</html>
    2、直接访问（不推荐使用，如果已经使用了 Struts 框架，则应该优先考虑使用 Struts 而不是使用 Servlet ）
    • 实现接口并提供 setter 方法（与servlet API 耦合大).）
    　　　　org.apache.struts2.util.ServletContextAware
    　　　　org.apache.struts2.interceptor.ServletRequestAware
    　　　　org.apache.struts2.interceptor.ServletResponseAware
    • 通过 ServletActionContext 类的静态方法
    　　　　org.apache.struts2.ServletActionContext.getPageContext()
    　　　　org.apache.struts2.ServletActionContext.getRequest()
    　　　　org.apache.struts2.ServletActionContext.getRequest().getSession()
    　　　　org.apache.struts2.ServletActionContext.getResponse()
    　　　　org.apache.struts2.ServletActionContext.getServletContext()

    转载请于明显处标明出处

    https://www.cnblogs.com/AmyZheng/p/9204047.html

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  • 原文地址：https://www.cnblogs.com/AmyZheng/p/9204047.html
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