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Struts2 语法--action

xml的注释:

web.xml注释格式":

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <welcome-file-list>
    <welcome-file>index.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>

namespace:

1. package:区分不同的action,

2. namespace为空, 随便找到index action处理,可以囊括其他package处理不了的.

输入/front/index 就会显示 Namespace.jsp

<package name="front" extends="struts-default" namespace="/front">
        <action name="index">
            <result name="success">/Namespace.jsp</result>
        </action>
    </package>
    
     <package name="main" extends="struts-default" namespace="">
        <action name="index">
            <result>/Namespace.jsp</result>
        </action>
    </package>

action:具体视图的返回可以由用户自己定义的action来决定.

/index 会访问 IndexAction1.class,通过返回的success,跳转到 ActionIntroduction.jsp

上面的例子,没有配置class则会执行ActionSurport, 自动返回一个success, 所以直接执行result里的jsp

 <constant name="struts.devMode" value="true" />
    <package name="front" extends="struts-default" namespace="/">
        <action name="index" class="com.bjsxt.struts2.front.action.IndexAction1">
            <result name="success">/ActionIntroduction.jsp</result>
        </action>
    </package>

action的标准模式:

public class IndexAction3 extends ActionSupport {
	
	@Override
	public String execute() {
		return "success";
	}
}

path:

jsp文件中有这个样的连接:

<a href="path/path.action">路径问题说明</a>

要去struts.xml去找namespace为path, action为path的, 再去看class里找到pathaction.class,返回值为path跳转到path.jsp

 <constant name="struts.devMode" value="true" />
    <package name="path" extends="struts-default" namespace="/path">
        <action name="path" class="com.bjsxt.struts2.path.action.PathAction">
            <result name="path">/path.jsp</result>
        </action>
    </package>

path.jsp:

<a href="index.jsp">index.jsp</a>

这样是不可以的,虽然path.jsp和index.jsp在同一目录. 去找的是 /path/index.jsp,如何解决:

<%
　　String path = request.getContextPath();
　　String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!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>
<base href="<%=basePath%>" />

所以,Struts2的路径问题是根据action的路径而不是jsp的路径来决定的. 所以尽量不要使用相对路径.要使用绝对路径.

jsp中使用request.getContextRoot获取webapp的路径. myeclipse指定basepath

动态调用DMI Dynamic Method Invoking:

action执行不一定要执行execute方法, 看下面的例子:

<?xml version="1.0" encoding="UTF-8" ?>
<!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.devMode" value="true" />
    <package name="user" extends="struts-default" namespace="/user">
        <action name="userAdd" class="com.bjsxt.struts2.user.action.UserAction" method="add">
            <result>/user_add_success.jsp</result>
        </action>
        
        <action name="user" class="com.bjsxt.struts2.user.action.UserAction">
            <result>/user_add_success.jsp</result>
        </action>
    </package>
</struts>

jsp调用方法:

第2种方法比较好, 动态调用, 找namespace为user, action为user, 方法由jsp里调用时的add选择.

<a href="<%=context %>/user/userAdd">添加用户</a>
	<br />
<a href="<%=context %>/user/user!add">添加用户</a>
	<br />

通配符配置:

struts.xml文件:

<!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.devMode" value="true" />
    <package name="actions" extends="struts-default" namespace="/actions">
        <action name="Student*" class="com.bjsxt.struts2.action.StudentAction" method="{1}">
            <result>/Student{1}_success.jsp</result>
        </action>
        
        <action name="*_*" class="com.bjsxt.struts2.action.{1}Action" method="{2}">
            <result>/{1}_{2}_success.jsp</result>
            <!-- {0}_success.jsp -->
        </action>
    </package>
</struts>

调用jsp:

<% String context = request.getContextPath(); %>

<a href="<%=context %>/actions/Studentadd">添加学生</a>
<a href="<%=context %>/actions/Studentdelete">删除学生</a>
<br />
不过，一定要遵守"约定优于配置"的原则
<br />
<a href="<%=context %>/actions/Teacher_add">添加老师</a>
<a href="<%=context %>/actions/Teacher_delete">删除老师</a>
<a href="<%=context %>/actions/Course_add">添加课程</a>
<a href="<%=context %>/actions/Course_delete">删除课程</a>

用action属性接收参数:

jsp文件:

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030" />
<base href="<%=basePath %>"/>
<title>Insert title here</title>
</head>
<body>
使用action属性接收参数<a href="user/user!add?name=a&age=8">添加用户</a>
	
</body>
</html>

struts.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!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.devMode" value="true" />
    <package name="user" extends="struts-default" namespace="/user">
        
        <action name="user" class="com.bjsxt.struts2.user.action.UserAction">
            <result>/user_add_success.jsp</result>
        </action>
    </package>
</struts>

user.java:

package com.bjsxt.struts2.user.action;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport {

private String name;
private int age;

public String add() {
System.out.println("name=" + name);
System.out.println("age=" + age);
return SUCCESS;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}
}

1. 由user/user!add?name=a&age=8 找xml里的namespace为user,action为user的add方法,同时传入两个值给action

2. 需要在action里设置同名属性name和age,此处同名指的是getName,和getAge.

用DomainModel接收参数:

调用jsp:

<!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" />
<base href="<%=basePath %>"/>
<title>Insert title here</title>
</head>
<body> 
使用Domain Model接收参数<a href="user/user!add?user.name=a&user.age=8">添加用户</a>
	
</body>
</html>

useraction.java文件:

相当于调用了setUser().setName()

public class UserAction extends ActionSupport {
	
	private User user;  //自己new
	//private UserDTO userDTO;
	public String add() {
		System.out.println("name=" + user.getName());
		System.out.println("age=" + user.getAge());
		return SUCCESS;
	}

	public User getUser() {
		return user;
	}

	public void setUser(User user) {
		this.user = user;
	}
}

vo: user.java:

public class User {
	private String name;
	private int age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
}

DTO: userdto.java: data transfer object

package com.bjsxt.struts2.user.dto;

public class UserDTO {
	private String name;
	private String password;
	private String confirmingPassword;
}

modeldriven接收参数: 面向对象思想: V: jsp M: Model类, C:各种action , action来负责M, V沟通,并解耦和

useraction.java: C

package com.bjsxt.struts2.user.action;

import com.bjsxt.struts2.user.model.User;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

public class UserAction extends ActionSupport implements ModelDriven<User>{
	
	private User user = new User();  //必须自己new
	
	public String add() {
		System.out.println("name=" + user.getName());
		System.out.println("age=" + user.getAge());
		return SUCCESS;
	}

	@Override
	public User getModel() {
		return user;
	}	
}

jsp:

<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>

<% 
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!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" />
<base href="<%=basePath %>"/>
<title>Insert title here</title>
</head>
<body> 
使用ModelDriven接收参数<a href="user/user!add?name=a&age=8">添加用户</a>
	
</body>
</html>

总结:接收参数用第二种 DomainModel.

接收参数的中文问题:

jsp:

<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>

<% 
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!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" />
<base href="<%=basePath %>"/>
<title>Insert title here</title>
</head>
<body>
使用action属性接收参数，测试中文问题
<form action="user/user!add" method="post">
姓名：<input type="text" name="name"></input>
<input type="submit" value="submit"/>
</form>

	
</body>
</html>

提交中文后乱码,如何解决?

struts里已经设置,还是不行 :

<?xml version="1.0" encoding="UTF-8" ?>
<!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.devMode" value="true" />
    <constant name="struts.i18n.encoding" value="GBK" /> <!-- internationalization -->
    <package name="user" extends="struts-default" namespace="/user">
        <action name="userAdd" class="com.bjsxt.struts2.user.action.UserAction" method="add">
            <result>/user_add_success.jsp</result>
        </action>
        
        <action name="user" class="com.bjsxt.struts2.user.action.UserAction">
            <result>/user_add_success.jsp</result>
        </action>
    </package>
</struts>

　答案,配置web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <filter>
        <filter-name>struts2</filter-name>
        <!-- <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>-->
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

简单数据验证:

jsp文件:

使用addFieldError方法和s:fieldError标签简单处理数据校验
<a href="user/user!add?name=a" >添加用户</a>

struts.xml:

<struts>
    <constant name="struts.devMode" value="true" />
    <package name="user" extends="struts-default" namespace="/user">
        <action name="user" class="com.bjsxt.struts2.user.action.UserAction">
            <result>/user_add_success.jsp</result>
            <result name="error">/user_add_error.jsp</result>
        </action>
    </package>
</struts>

useraction.java:

想往前台传信息,可以用response或者request.setparameters, 但是action访问不到request,response

public class UserAction extends ActionSupport {
	private String name;
	
	public String add() {
		if(name == null || !name.equals("admin")) {
			this.addFieldError("name", "name is error");
			this.addFieldError("name", "name is too long");
			return ERROR;
		} 
		return SUCCESS;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}	
}

登录不成功的时候user_add_error.jsp:

<body>
	User Add Error!
	<s:fielderror fieldName="name" theme="simple"/>
	<br />
	<s:property value="errors.name[0]"/>
	<s:debug></s:debug>
</body>
</html>

　　Action获取前台数据:request,session,application

后台的action是拿不到前台的request, response等,

如果前台输入用户名和密码什么的,放入session里,如果action获取不到session怎么办呢?

如何让action获取 request,session, application等外部元素?

index.jsp:

<body>
取得Map类型request,session,application,真实类型 HttpServletRequest, HttpSession, ServletContext的引用:
<ol>
	<li>前三者：依赖于容器</li>
	<li>前三者：IOC</li> (只用这种)
	<li>后三者：依赖于容器</li>
	<li>后三者：IOC</li>
</ol>
<br />
<form name="f" action="" method="post">
用户名：<input type="text" name="name"/>
密码：<input type="text" name="password"/>
<br />
<input type="button" value="submit1" onclick="javascript:document.f.action='login/login1';document.f.submit();" />
<input type="button" value="submit2" onclick="javascript:document.f.action='login/login2';document.f.submit();" />
<input type="button" value="submit3" onclick="javascript:document.f.action='login/login3';document.f.submit();" />
<input type="button" value="submit4" onclick="javascript:document.f.action='login/login4';document.f.submit();" />
</form>
	
</body>

　struts.xml:

<struts>
    <constant name="struts.devMode" value="true" />
    <package name="login" extends="struts-default" namespace="/login">
        <action name="login*" class="com.bjsxt.struts2.user.action.LoginAction{1}">
            <result>/user_login_success.jsp</result>
        </action>
    </package>
</struts>

最重要的处理action:

package com.bjsxt.struts2.user.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.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {
	
	private Map<String, Object> request;
	private Map<String, Object> session;
	private Map<String, Object> application;
	
	//DI dependency injection
	//IoC inverse of control
	public String execute() {
		request.put("r1", "r1");
		session.put("s1", "s1");
		application.put("a1", "a1");
		return SUCCESS; 
	}

	@Override
	public void setRequest(Map<String, Object> request) {
		this.request = request;
	}

	@Override
	public void setSession(Map<String, Object> session) {
		this.session = session;
	}

	@Override
	public void setApplication(Map<String, Object> application) {
		this.application = application;
	}
}

返回成功的jsp:

<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
    <%@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>

模块包含:

<include file="login.xml"/>

意义:多人平台开发的时候, 大家写各自的xml,　

默认action:

使用目的:当访问当前的namespace下的action,找不到actoin的时候, 就可以自动选择index这个action

<default-action-ref name="index"></default-action-ref>
<action name="index">
　　<result>/default.jsp</result>
<action>

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原文地址：https://www.cnblogs.com/wujixing/p/5169707.html