Struts笔记2

超、凢脫俗 2021-12-03 06:41 321阅读 0赞

**Struts2-配置文件result元素**

作用：为动作指定结果视图

name属性：逻辑视图的名称，对应着动作方法的返回值。默认值是success

type属性:结果类型，指的就是用什么方式转到定义的页面，默认是dispatcher

result中type的取值有四种类型

<table> 
 <tbody> 
  <tr> 
   <td>dispatcher</td> 
   <td style="text-align:left;">默认值使用请求转发，转向一个页面</td> 
  </tr> 
  <tr> 
   <td>redirect</td> 
   <td style="text-align:left;">使用重定向，转向一个页面</td> 
  </tr> 
  <tr> 
   <td>chain</td> 
   <td style="text-align:left;">转发到另一个相同名称空间的动作，转发到不同名称空间的动作</td> 
  </tr> 
  <tr> 
   <td>redirectAction</td> 
   <td style="text-align:left;">重定向到另一个相同名称空间的动作，重定向到不同名称空间的动作</td> 
  </tr> 
 </tbody> 
</table>

**result元素 转发与重定向**

dispatcher:是转发到一个页面(jsp)

chain:是转发到一个action

redirect：重定向一个页面

redirectAction:重定向到另一个action

![img][]

![img][img 1]

**自定义结果类型**

上面的重定向，转发都是结果类型

结果类型就是一个类，这些类都是些com.opensymphony.xwork2.Result接口,或者继承自接口的实现类org.apache.struts2.dispatcher.StrutsResultSupport

这些类都有一个doExecute方法，用于执行结果视图，struts的内部实现就是Servlet

自定义验证码结果类型

package com.gyf.web.result;
    
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.struts2.ServletActionContext;
    import org.apache.struts2.dispatcher.StrutsResultSupport;
    
    import com.opensymphony.xwork2.ActionInvocation;
    
    import cn.dsna.util.images.ValidateCode;
    
    public class CAPTCHAResult extends StrutsResultSupport{
        private int width;
        private int height;
        @Override
        protected void doExecute(String arg0, ActionInvocation arg1) throws Exception {
            //生成验证码
            //创建一个验证码对象
            ValidateCode code = new ValidateCode(width,height,4,6);
            //获取response对象，因为要返回给客户端
            HttpServletResponse response = ServletActionContext.getResponse();
            code.write(response.getOutputStream());//write方法可以把图片写回给客户端，但是需要一个输出流
        }
        public int getHeight() {
            return height;
        }
        public int getWidth() {
            return width;
        }
        public void setWidth(int width) {
            this.width = width;
        }
        public void setHeight(int height) {
            this.height = height;
        }
        
        
    }

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">
    
    <struts>
        
       <constant name="struts.devMode" value="true"></constant>
       
       
       <package name="p1" extends="struts-default" namespace="/n1">     
            
            <result-types>
                <result-type  name="captcha" class="com.gyf.web.result.CAPTCHAResult"></result-type>
            </result-types> 
            
            <action name="checkcode">
                <result type="captcha">
                    <param name="width">150</param>
                    <param name="height">60</param>
                 </result>
            </action>
       </package>
    </struts>

**result元素-全局视图和局部视图**

![img][img 2]

![img][img 3]

**Struts2-动作类中的servlet api 访问讲解**

第一种方式

package com.gyf.web.action;
    
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.ServletActionContext;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class TestAction extends ActionSupport{
        public String test() {
            //获取servlet 的api方式
            //第一种方式：通过ServletActionContext
            //response
            HttpServletResponse response = ServletActionContext.getResponse();
            //request
            HttpServletRequest request = ServletActionContext.getRequest();
            //session
            HttpSession session = request.getSession();
            //application[ServletContext]
            ServletContext application = ServletActionContext.getServletContext();
            
            
            System.out.println(request);
            System.out.println(response);
            System.out.println(session);
            System.out.println(application);
            
            
            //NONE相当于不用跳转页面，也就是相当于不用找result标签,
            return NONE;
        }
    }

第二种方式

package com.gyf.web.action;
    
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.ServletActionContext;
    import org.apache.struts2.interceptor.ServletRequestAware;
    import org.apache.struts2.interceptor.ServletResponseAware;
    import org.apache.struts2.util.ServletContextAware;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class TestAction2 extends ActionSupport implements ServletRequestAware,ServletResponseAware,ServletContextAware{
        HttpServletResponse response;
        HttpServletRequest request;
        ServletContext application;
        public String test() {
            //第二种方式，通过实现接口，让Struts自动注入
            System.out.println(request);
            System.out.println(response);
            System.out.println(application);
            
            
            //NONE相当于不用跳转页面，也就是相当于不用找result标签,
            return NONE;
        }
        @Override
        public void setServletResponse(HttpServletResponse response) {
            this.response=response;
            
        }
        @Override
        public void setServletRequest(HttpServletRequest request) {
            this.request=request;
            
        }
        @Override
        public void setServletContext(ServletContext application) {
            this.application=application;
            
        }
    }

**Action接收请求参数**

通过Servlet和Action的属性set方法注入获取参数

package com.gyf.web.action;
    
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.ServletActionContext;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class LoginAction extends ActionSupport{
        //第二种方式通过属性的set注入
        private String username;
        private String password;
        
        public String login() {
            //第一种方式：通过ServletActionContext
            //request
    //      HttpServletRequest request = ServletActionContext.getRequest();
    //      String username = request.getParameter("username");
    //      String password = request.getParameter("password");
            
            System.out.println(username);
            System.out.println(password);
            //NONE相当于不用跳转页面，也就是相当于不用找result标签,
            return NONE;
        }
        
        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;
        }
    
        
    }

**第三种方式通过Action的属性的set模型的形式注入**

**第四种方式通过模型驱动在action里实现一个模型驱动接口**

实现步骤：

在action里实现一个模型驱动接口

提供一个模型属性，并一定要赋值

实现原理：是因为有个模型驱动的拦截器在处理，ModelDrivenIngetrceptor，处理过程中给User赋予值

package com.gyf.web.model;
    
    public class User {
        private String username;
        private String password;
        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;
        }
        @Override
        public String toString() {
            return "User [username=" + username + ", password=" + password + "]";
        }
        
    }

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    
    <form action="${pageContext.request.contextPath}/login.action">
        用户名<input type="text" name="username"><br>
        密码<input type="password" name="password"><br>
        <input type="submit" name="登录">
    </form>
    
    
    
    </body>
    </html>

转载于:https://www.cnblogs.com/train99999/p/11144681.html

[img]: https://www.z4a.net/images/2019/07/06/image.png
[img 1]: https://www.z4a.net/images/2019/07/06/image94d03a6563c35afe.png
[img 2]: https://www.z4a.net/images/2019/07/06/imagebc6243fa2367ebb2.png
[img 3]: https://www.z4a.net/images/2019/07/06/image61c1bc8820b62011.png