• Struts2>action 小强斋


    Action

     

    具体视图的返回可以由用户自己定义的Action来决定,具体的手段是根据返回的字符串找到对应的配置项,来决定视图的内容

    一、具体Action的实现
    1、可以是一个普通的java类,里面有public String execute方法即可

    package com.ncepu.struts;
    
    public class Action1 {
    	public String execute()
    	{
    		System.out.print("在普通类中定义execute()方法");
    		return("success");
    	}
    
    
    }
    

    2、或者实现Action接口

    package com.ncepu.struts;
    
    import com.opensymphony.xwork2.Action;
    
    public class Action2 implements Action {
    
    
    	public String execute() throws Exception {
    	System.out.print("实现Action接口");
    		return "success";
    	}
    }
    

    3、不过最常用的是从ActionSupport继承,好处在于可以直接使用Struts2封装好的方法

    package com.ncepu.struts;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class Action3 extends ActionSupport {
    	public String execute()
    	{
    		System.out.print("继承ActionSupport类");
    		return("success");
    	}
    
    
    }
    

    二、helloworld 例子中里面action没有配置class

    <action name="hello">
    	    <result>
    				/index.jsp
                </result>
    		</action>

    就是默认为ActionSupport,里面的execute方法返回success   

    public String execute() throws Exception {
            return SUCCESS;
        }

    三、DMI(dynami method invocation)动态方法调用

    1、action不一定非得执行execute方法,可以指定调用具体的方法。不写的话默认为execute方法

        action方法中的method方法指定调用具体的方法。

    <action name="action1" class="com.ncepu.struts2.Action1" method="notexecute">
       <result name="success">
        /index.jsp
       </result>
      </action>

    2、DMI 动态方法调用 用!号

    <action name="user" class="com.ncepu.struts2.Action1" >
       <result name="success">
        /add.jsp
         </result>
      </action>

    jsp中<a href="user!add">添加学生</a>  自动调用Action1下面的add方法
    也可直接访问 
    http://localhost:8080/Struts2_DMI/user!add

    四、通配符
     action配置 

    <action name="*_*" class="com.ncepu.struts2.{1}Action" method="{2}{1}">
       <result name="success">
        /{2}_{1}.jsp
                </result>
      </action> 

    jsp页面链接   

      <a href="Student_add">添加学生</a>
      <a href="Student_delete">删除学生</a>
      <a href="Teacher_add">添加教师</a>
      <a href="Teacher_delete">删除教师</a>

    也可直接访问http://localhost:8080/Struts2_tongpeifu2/Student_delete思考: 仅用动态方法调用,result对于不同的action无法配置。要不只能到学生的jsp 要不只能到教师的jsp。
    五、action接收参数
    1、<a href="user!add?name=12345&password=12345">添加学生</a> 其中name和password是 action中的参数,并且有相应的getter和setter方法
    2、使用Domain Model接收参数(最常用)

    <a href="user/user!add?user.name=a&user.password=8">添加用户</a>
    其中user是action中的参数,有getter和setter方法,而user是我们自己定义的域模型,里面有name和password参数

    package com.ncepu.struts2;
    
    import com.ncepu.struts2.entity.User;
    
    public class Action1 {
    
    private User user;
    
    	public User getUser() {
    	return user;
    }
    
    public void setUser(User user) {
    	this.user = user;
    }
    
    	public String add() {
            System.out.println("添加的name="+this.user.getName()+"添加的password="+this.user.getPassword());
    		return ("success");
    	}
    
    }
    

    或者用DTO传输数据,相当于VO  value object ),比如注册的时候,得输入两遍密码,可以定义一个vo,包含3个属性,用户名,密码,确认密码,然后根据vo生成实体,该实体只包含用户名和密码两个属性。

    3、使用ModelDriven接收参数

    action实现ModelDriven接口,里面生成一个模型对象

    public class Action1 extends ActionSupport implements ModelDriven<User>{
     private User user = new User();
     public String add() {
      System.out.println("name=" + user.getName());
      System.out.println("age=" + user.getPassword());
      return SUCCESS;
     }
     public User getModel() {
      return user;
     }
     
    }

    <a href="user/user!add?name=a&password=8">添加用户</a> 

    会直接把属性设置到getModel方法获得的模型上面。

    六、中文乱码问题

     <form action="user!add" method="post">  必须为post ,get就出错,action得不到值

    七、简单验证

     public String add() {
      if(name == null || !name.equals("admin")) {
       this.addFieldError("nameerror", "name is error");
       this.addFieldError("nameerror", "name is too long");
       this.addFieldError("passworderror", "password is not correct!");
       return ERROR;
      } 
      return SUCCESS;
     
     }

    相应的在页面上

      <s:fielderror fieldName="nameerror" theme="simple" />
      <s:fielderror fieldName="passworderror" theme="simple" />
      <s:property value="errors.nameerror" />  <s:property value="errors.nameerror[0]" />
      <s:property value="errors.nameerror[1]" />
      <s:property value="errors.passworderror" /><s:property value="errors.passworderror[0]" />
      <s:debug></s:debug>

    errors fieldErrors和action中所有的属性都会存在Value Stack Contents中
    fielderror相当于一个数组,可以取所有,也可以取一个。
    八、获得web元素4种方法

    map类型的request session application(1、通过容器获得,2、实现aware接口通过IoC获得)

    真实类型的request session application(3、通过容器获得,4、实现aware接口通过IoC获得)

    1、通过容器获得map类型的request session application

    package com.struts2.action;
    
    import java.util.Map;
    
    import com.opensymphony.xwork2.ActionContext;
    import com.opensymphony.xwork2.ActionSupport;
    
    public class Action1 extends ActionSupport {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	private Map<String, Object> request;
    	private Map<String, Object> session;
    	private Map<String, Object> application;
    
    	public Action1() {
    		request = (Map) ActionContext.getContext().get("request");
    		session = ActionContext.getContext().getSession();
    		application = ActionContext.getContext().getApplication();
    	}
    
    	public String execute() {
    		request.put("r1", "requestpara");
    		session.put("s1", "sessionpara");
    		application.put("a1", "applicationpara");
    		return SUCCESS;
    
    	}
    
    }
    

    2、实现aware接口通过IoC获得map类型的request session application,(最常用)

    package com.struts2.action;
    
    import java.util.Map;
    
    import org.apache.struts2.interceptor.ApplicationAware;
    import org.apache.struts2.interceptor.RequestAware;
    import org.apache.struts2.interceptor.SessionAware;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class Action2 extends ActionSupport implements RequestAware,
    		SessionAware, ApplicationAware {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	private Map<String, Object> request;
    	private Map<String, Object> session;
    	private Map<String, Object> application;
    
    	public void setRequest(Map<String, Object> request) {
    		this.request = request;
    
    	}
    
    	public void setSession(Map<String, Object> session) {
    		this.session = session;
    	}
    
    	public void setApplication(Map<String, Object> application) {
    		this.application = application;
    
    	}
    
    	public String execute() {
    		request.put("r1", "requestpara");
    		session.put("s1", "sessionpara");
    		application.put("a1", "applicationpara");
    		return SUCCESS;
    
    	}
    }
    

    3、通过容器获得真实类型的request session application

    package com.struts2.action;
    
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.ServletActionContext;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class Action3 extends ActionSupport {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	HttpServletRequest request;
    	HttpSession session;
    	ServletContext application;
    
    	public Action3() {
    		request = ServletActionContext.getRequest();
    		session = request.getSession();
    		application = session.getServletContext();
    	}
    
    	public String execute() {
    		request.setAttribute("r1", "requestpara");
    		session.setAttribute("s1", "sessionpara");
    		application.setAttribute("a1", "applicationpara");
    		return SUCCESS;
    
    	}
    
    }
    

    4、实现aware接口通过IoC获得真实类型的request session application

    package com.struts2.action;
    
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.interceptor.ServletRequestAware;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    public class Action4 extends ActionSupport implements ServletRequestAware {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	HttpServletRequest request;
    	HttpSession session;
    	ServletContext application;
    
    	public void setServletRequest(HttpServletRequest request) {
    		this.request = request;
    		this.session = request.getSession();
    		application = session.getServletContext();
    
    	}
    
    	public String execute() {
    		request.setAttribute("r1", "requestpara");
    		session.setAttribute("s1", "sessionpara");
    		application.setAttribute("a1", "applicationpara");
    		return SUCCESS;
    
    	}
    }
    

    login_success.jsp

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
        <%@taglib uri="/struts-tags" prefix="s" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=GB18030" />
    <title>Insert title here</title>
    </head>
    <body>
    	User Login Success!
    	<br />
    	<s:property value="#request.r1"/> | <%=request.getAttribute("r1") %> <br />
    	<s:property value="#session.s1"/> | <%=session.getAttribute("s1") %> <br />
    	<s:property value="#application.a1"/> | <%=application.getAttribute("a1") %> <br />
    	<s:property value="#attr.a1"/><br />
    	<s:property value="#attr.s1"/><br />
    	<s:property value="#attr.r1"/><br />
    	<s:debug></s:debug>
    	<br />
    </body>
    </html>

    九、include 包含其他配置action的xml文件

    <struts>
     <constant name="struts.devMode" value="true" />
     <include file="module1.xml"></include>
    </struts>

    而module1.xml文件中配置着action

    十、namespace的默认action

    <struts>
     <constant name="struts.devMode" value="true" />
    	<package name="default" namespace="/action" extends="struts-default">
    	<default-action-ref name="action1"></default-action-ref>
    	<action name="action1" class="com.ncepu.struts2.Action1">
    			<result name="success">
    				/default.jsp
                </result>
    	</action>	
    	</package>
    </struts>

    每个package可以有一个默认的action,当没有匹配的时候时,就使用它,如用户输入错误时,根据他跳到默认的错误界面

    十一、路径问题

    1、action跳转

    result都需要指定目标资源的URL,如果这个路径以“/”开始。代表的是应用程序根目录。

    <package name="default" namespace="/path" extends="struts-default">
    	
    		<action name="hello">
    			<result>
    				/path.jsp
                            </result>
    		</action>
    	</package>

    其中path在webroot根目录下。能找到。如果是下面的配置

    <package name="default" namespace="/path" extends="struts-default">
    	
    		<action name="hello">
    			<result>
    				path.jsp
                            </result>
    		</action>
    	</package>

    则不行,当前目录是Struts2_path/path/hello.action,相当于在当前目录查找,即/Struts2_path/path/path.jsp

    2、jsp链接都使用绝对路径:

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    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>My JSP 'index.jsp' starting page</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">
    	<!--
    	<link rel="stylesheet" type="text/css" href="styles.css">
    	-->
      </head>
      
      <body>
      <a href="path.jsp"> path.jsp</a> <br>
      </body>
    </html>
    

    定义path ,然后再head便签中添加<base href="<%=basePath%>">,相当于都从web应用的根目录下面找

     

     

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  • 原文地址:https://www.cnblogs.com/xiaoqiangzhaitai/p/5637561.html
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