JavaWeb -- Struts2，对比， 简单表单提交，校验，防重复提交， 文件上传

Struts2核心流程图

1. Struts2 和 Struts1 对比

struts1:基于Servlet(ActionServlet),actionForm众多(类的爆炸),action单例(数据安全[线程安全]问题).
  将所有任务的解决都集于一身.(不容易扩展和定制)
  action位于控制层. extends Action{...}
  action更struts1的action和原生servlet api(HttpServletRequest,HttpServlerResponse)绑定在一起,
  因此不容易测试,需要部署到web容器中进行测试.
  回显数据:struts-html.tld <html:checkbox> html:text
  struts-bean.tld
  struts-logic.tld
  //
  class CustomerAction extends DispatchAction{
   public ActionForward save(ActionMapping ActionForm Request,Response){

   }
   public ActionForward update(ActionMapping ActionForm Request,Response){

   }
  }

  <action-mappings>
   <action path="/customerAction"
     name="customerForm"
     scope="request|session"
     validate="true"
     input="/xxx.jsp"
     type="xxxx..CustomerAction"
     parameter="method" />
  http://xxx/sss/customerAction.do?method=save

struts2:基于filter,没有actionform,action(原型的,独占).
  seperate aware:分离关注.解耦.(interceptor,拦截器).
  action是模型层(接受参数+pojo).
  action不需要和struts的action和原生servlet API(HttpServletRequest,HttpServlerResponse)耦合在一起.
  所以更容易测试,不需要一定要部署到web环境中进行测试.
  struts2是更加整洁的mvc框架(原因是采用了seperate aware技术,实现任务的拆解).
体验struts2：
 1.创建web项目
 2.引入struts2类库
  ${struts解压目录}/app/struts2-blank-2.1.8.1.war/web-inf/lib/*.jar
 3.创建action.
  package cn.itcast.struts2.action;

  /**
   * HelloWorldAction
   */
  public class HelloWorldAction {
   public String execute(){
    System.out.println("hello world");
    return null ;
   }
  }
 4.创建struts配置文件.src/struts.xml
  dtd:struts-core.jar/struts-2.1.7.dtd/30行
  <?xml version="1.0"?>
  <!DOCTYPE struts PUBLIC
   "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
   "http://struts.apache.org/dtds/struts-2.1.7.dtd">
  <struts>
   <package name="HelloWorldPkg" namespace="/helloworld">
    <action name="HelloWorldAction" class="cn.itcast.struts2.action.HelloWorldAction" />
   </package>
  </struts>
 5.配置struts2的过滤器web-inf/web.xml文件中
  类:org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
  <?xml version="1.0" encoding="UTF-8"?>
  <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
   <filter>
    <filter-name>action</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
   </filter>
   <filter-mapping>
    <filter-name>action</filter-name>
    <url-pattern>/*</url-pattern>
   </filter-mapping>
   
   <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
  </web-app>

struts2包搜索顺序:
 http://localhost:8085/lsn_struts2/helloworld/aaa/bbb/HelloWorldAction.action
 http://localhost:8085/lsn_struts2/helloworld/aaa/bbb/
 http://localhost:8085/lsn_struts2/helloworld/aaa/
 http://localhost:8085/lsn_struts2/helloworld

list lst = .. ;
request.setAttribute("list",list); Map<String,Object>
request.getRequestDispatcher("/xxxx.jsp").forward(request,response);

HttpServletResponse.sendRedirect("/xx");

ContentType:
response.setContentType("text/html");
mime:

(HttpServletRequest)request.getAttribute("list");
request.setAttribute("list",list);

map:Sessoin (ServletContext)Application.setAttri

使用Token拦截器避免表单重复提交:
 1.在jsp页面上使用<s:token />
 2.在拦截器栈中加入token拦截器.

Google:
Web:异步执行.

2. 实例： 表单提交 ，校验，防重复提交，文件上传

web.xml 配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <filter>
        <filter-name>action</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>action</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

struts.xml配置  包含模块 reg.xml

<?xml version="1.0"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
    "http://struts.apache.org/dtds/struts-2.1.7.dtd">
<struts>
    
    <!-- 通过常量方式改变struts默认的属性配置, -->
    <constant name="struts.action.extension" value="do" />
    <!-- 设置开发模式,重新加载国际化资源文件和配置文件 -->
    <constant name="struts.devMode" value="true" />
    <!-- 动态方法调用 -->
    <constant name="struts.enable.DynamicMethodInvocation" value="true" />
    
    <package name="HelloWorldPkg" namespace="/helloworld" extends="struts-default">
        <!-- 默认该包下默认的action引用,若该包没有要访问的action元素,则使用默认的action引用 -->
        <default-action-ref name="HelloWorldAction" />
        
        <!-- 设置默认的class引用,将摸个类作为默认的action类 -->
        <default-class-ref class="cn.itcast.struts2.action.HelloWorldAction" />
        
        <!-- 通过通配符的方式实现动态方法调用 -->
        <action name="HelloWorldAction_*" class="cn.itcast.struts2.action.HelloWorldAction" 
		method="{1}">
            <result name="success">/index.jsp</result>
            <result name="save">/index.jsp</result>
            <result name="update">/success.jsp</result>
        </action>

        <!-- 没有类的action -->
        <action name="ActionNoClass">
            <result>/index.jsp</result>
        </action>
    </package>
    <!-- 模块话编程,包含配置文件 -->
    <include file="cn/itcast/struts2/action/reg.xml" />
</struts>

reg.xml  配置

<?xml version="1.0"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
    "http://struts.apache.org/dtds/struts-2.1.7.dtd">
<struts>
    <package name="RegPkg" namespace="/regns" extends="struts-default">
        <action name="RegAction_*" class="cn.itcast.struts2.action.RegAction" method="{1}">
            <result name="success">/reg/success.jsp</result>
            <result name="error">/reg/error.jsp</result>
            <result name="regView">/reg/reg.jsp</result>
            <result name="input">/reg/reg.jsp</result>
            <interceptor-ref name="defaultStack">   <!--动态方法调用，方式之一-->
                <param name="validation.excludeMethods">input,back,cancel,toRegView</param>
            </interceptor-ref>
        </action>
    </package>
</struts>

token.xml 防止重复提交 配置

<?xml version="1.0"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
    "http://struts.apache.org/dtds/struts-2.1.7.dtd">
<struts>
    <package name="TokenPkg" namespace="/token" extends="struts-default">
        <action name="TokenAction_*" class="cn.itcast.struts2.token.TokenAction" method="{1}">
            <result name="success">/token/success.jsp</result>
            <result name="regView">/token/reg.jsp</result>
			<!--无效令牌-->
            <result name="invalid.token">/token/reg.jsp</result>
            <result name="wait">/wait.jsp</result>
            <!-- 如果指定了一个拦截器,则覆盖默认的配置,必须手动指定默认栈 -->
            <interceptor-ref name="token">
                <param name="excludeMethods">toRegView,findAllCustomers</param>
            </interceptor-ref>
            <interceptor-ref name="defaultStack" />
            <!-- 执行等待拦截器 -->
            <interceptor-ref name="execAndWait" />
        </action>
    </package>
</struts>

reg.jsp 表单提交 JSP， 使用struts-tags 标签，数据回显与校验

<%@ page language="java" contentType="text/html; charset=utf-8"%>
<%@taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>reg.jsp</title>
	</head>
	<body>
		<s:debug />
		<s:actionerror />
		<s:form namespace="/regns" action="RegAction_reg" method="post" enctype="multipart/form-data">
			<s:token />  <!--防止重复提交-->
			<s:textfield name="name" label="UserName" />
			<s:textfield name="age" label="UserAge" />
			<s:file name="photo" label="UserPhoto" />
			<s:submit />
		</s:form>
	</body>
</html>

RegAction.java  处理action

public class RegAction extends ActionSupport {

	private static final long serialVersionUID = 2941355104469235318L;
	private String name;
	private Integer age;
	
	/* 接受上传的文件 */
	private File photo ;
	/* 接受文件名称 */
	private String photoFileName ;
	/* 接受文件内容类型的 */
	private String photoContentType ;

	public String getPhotoFileName() {
		return photoFileName;
	}

	public void setPhotoFileName(String photoFileName) {
		this.photoFileName = photoFileName;
	}

	public String getPhotoContentType() {
		return photoContentType;
	}

	public void setPhotoContentType(String photoContentType) {
		this.photoContentType = photoContentType;
	}

	public String getName() {
		return name;
	}

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

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}
	
	/**
	 * 
	 */
	public String reg(){
		System.out.println("reg : " + name);
		String dir = ServletActionContext.getServletContext().getRealPath("/upload");
		String ext = photoFileName.substring(photoFileName.lastIndexOf("."));
		long l = System.nanoTime();
		File newFile = new File(dir,l + ext);
		photo.renameTo(newFile);
		return SUCCESS;
	}
	
	/**
	 * 达到注册页面, 动态方法调用之一， 使用SkipValidation标签掉过校验
	 */
	//@SkipValidation
	public String toRegView(){
		return "regView" ;
	}
	
	/**
	 * 动态方法调用之一，命名： validate + 要校验方法（Reg) == void validateReg() {}
	 */
	public void validate() {
		if(name == null || name.length() == 0){
		//国际化，getText会从配置文件获得message，配置文件名和类名一致，位置相同，RegAction.properties
			addFieldError("name",getText("error.name.empty"));
		}
	}

	public File getPhoto() {
		return photo;
	}

	public void setPhoto(File photo) {
		this.photo = photo;
	}
}

RegAction.properties 国际化配置文件

error.name.empty=name is required!
error.name.age=age is required!

success.jsp 成功跳转JSP

<%@ page language="java" contentType="text/html; charset=utf-8"%>
<%@taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>index.jsp</title>
	</head>
	<body>
		you input's name is <s:property value="name" />.<br>
		you input's age is <s:property value="age" />.<br>
	</body>
</html>

wait.jsp 等待页面

<%@ page language="java" contentType="text/html; charset=utf-8"%>
<%@taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>wait.jsp</title>
		<meta http-equiv="refresh" content="2;url=<s:url/>"/>
	</head>
	<body>
		处理中,请稍后....
	</body>
</html>