struts2 深入探索

Struts2中一些零碎的知识点:struts.xml详解、模型驱动、Preparable接口、防止表单重复提交、ActionContext、动态方法调用、异常

 

 

 

1、struts.xml详解
a. struts.properties
    在struts.xml中可以定义constant覆盖struts-core.jar/org/apache/struts2/default.properties中的设置。
    例:<constant name="struts.custom.i18n.resources" value="message"/>

    也可以直接新建struts.properties(与struts.xml在同一目录)，在struts.properties中配置。推荐在struts.properties中进行配置。
    例:struts.custom.i18n.resources = message

b. abstract package
    struts-core.jar/struts-default.xml，中有如下定义。
    <package name="struts-default" abstract="true">
        ......
    </package>
    其中abstract="true"中，表示在此package中不能定义Action(与Java abstract类相似)，仅供继承。

c. namespace
    strut.xml中:
    <package name="MyStruts" extends="struts-default" namespace="/mystruts">
    ......
    </package>

    默认命名空间为namespace=""，命名空间要以"/"开头。
    JSP访问:<s:form action="miscellaneous" namespace="/mystruts">。
    不能写成<s:form action="/mystruts/miscellaneous"> ，否则会发生错误:"No configuration found for the specified action: '/mystruts/miscellaneous' in namespace: '/miscellaneous'. Form action defaulting to 'action' attribute's literal value."[2]。

d. 模块化配置
    ......
    <struts>
        <include file="struts1.xml" />
        <package ...>
            ......
        </package>
    </struts>
    include中struts1.xml的编写与struts.xml是类似的。


2、属性驱动与模型驱动
属性驱动:直接在Action中写表单属性。

/StrutsHelloWorld/src/wintys/struts2/miscellaneous/MiscellaneousAction.java：

 

 

 

package wintys.struts2.miscellaneous;
import com.opensymphony.xwork2.ActionSupport;
/**
 * 
 * @author Winty ([e-mail])
 * @version 2009-8-24
 * @see http://wintys.blogjava.net
 */
@SuppressWarnings("serial")
public class MiscellaneousAction extends ActionSupport {
    private String name;
    private String password;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    
    @Override
    public String execute() throws Exception {
        return SUCCESS;
    }
}

 

 

 

模型驱动:将属性放到JavaBean中，Action需要实现com.opensymphony.xwork2.ModelDriven接口。ModelDrivenInterceptor 必须在之前StaticParametersInterceptor and ParametersInterceptor。这个顺序已在defaultStack Interceptor中定义。

/StrutsHelloWorld/src/wintys/struts2/miscellaneous/User.java:

 

 

 

 

package wintys.struts2.miscellaneous;
/**
 * 模型驱动Action中的模型
 * @author Winty ([e-mail])
 * @version 2009-8-25
 * @see http://wintys.blogjava.net
 */
public class User {
    private String name;
    private String password;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

 

 

 

/StrutsHelloWorld/src/wintys/struts2/miscellaneous/MiscellaneousModelDrivenAction.java:

 

 

 

package wintys.struts2.miscellaneous;
import com.opensymphony.xwork2.ModelDriven;

@SuppressWarnings("serial")
public class MiscellaneousModelDrivenAction extends ActionSupport implements
        ModelDriven<User>{
    
    private User user = new User();
    
    @Override
    public User getModel() {
        return user;
    }
    
    @Override
    public String execute() throws Exception {
        return SUCCESS;
    }
}

 

 

3、Preparable接口
    Action还可以实现com.opensymphony.xwork2.Preparable接口，用于准备Action自己。Preparable中的prepare方法在Action执行其它方法前执行。

4、使用simple 主题时，如何单独格式化Struts错误提示信息
    单独显示name字段的fielderror:

 

 

<s:fielderror>
    <s:param>name</s:param>
</s:fielderror>

 

 

5、Struts防止表单重复提交
    JSP页面中加入token和actionerror:
<s:actionerror />
<s:form .../>
    <s:token />
</s:form>

    token产生的actionerror的i18n key为:struts.message.invalid.token。

    在struts.xml中的Action配置中加入token interceptor，和invalid.token result:

 

 

<action name="miscellaneous" class="wintys.struts2.miscellaneous.MiscellaneousModelDrivenAction">
            <result name="success">/miscellaneous/output.jsp</result>
            <result name="input">/miscellaneous/input.jsp</result>

            <result name="invalid.token" >/miscellaneous/input.jsp</result>
            <interceptor-ref name="token" />
            <interceptor-ref name="defaultStack" />
        </action>

 

 生成的JSP页面如下:
    <input type="hidden" name="struts.token.name" value="struts.token" />
    <input type="hidden" name="struts.token" value="ORU0RZIP8JWQ7BDZG4P1NJSEKITGG6X5" />

    struts.token.name指<s:token />中的name，默认为struts.token。也可以自己指定<s:token name="mytoken" />。则生成如下token:
    <input type="hidden" name="struts.token.name" value="mytoken" />
    <input type="hidden" name="mytoken" value="GFD13EW206G2DY9AB3SRIAVXXT1S915C" />

6、通过Struts获取Servlet API
    一般Java Web程序不能离开容器进行测试。容器内测试常用框架:Cactus(jakarta.apache.org/cactus/index.html) 、Mock。

    通过Struts获取Servlet API，使程序可脱离容器测试。Struts中可通过如下方法获取Servlet API:ActionContext 、ServletActionContext、ServletXXXAware。首选ActionContext，其次选择ServletActionContext，再次ServletXXXAware。

a. ActionContext
    com.opensymphony.xwork2.ActionContext.getActionContext()获取ActionContext实例。

    ActionContext的get()和put()方法与HttpServletRequest的对应关系:
    ActionContext.get() <=> HttpServletRequest.getAttribute()
    ActionContext.put() <=> HttpServletRequest.setAttribute()

    例:

ActionContext context = ActionContext.getContext();
 context.put("info", "this is ActionContext value");

 但是ActionContext无法获取Servlet HttpResponse对象。

b. ServletActionContext
    org.apache.struts2.ServletActionContext是com.opensymphony.xwork2.ActionContext的子类。

    使用静态方法直接获取Servlet对象:
    Request: ServletActionContext.getRequest();
    Response: ServletActionContext.getResponse();
    Session: ServletActionContext.getRequest().getSession();

    例:

Cookie cookie = new Cookie("mycookie" , "10000");
        HttpServletResponse response = ServletActionContext.getResponse();
        response.addCookie(cookie);

 c. ServletXXXAware接口

    org.apache.struts2.util.ServletContextAware接口
    org.apache.struts2.interceptor.ServletRequestAware接口
    org.apache.struts2.interceptor.ServletResponseAware接口
    org.apache.struts2.interceptor.SessionAware接口

    实现ServletXXXAware接口的Action会被Struts自动注入相应的Servlet对象。

    例:

package wintys.struts2.miscellaneous;

import org.apache.struts2.interceptor.ServletRequestAware;
import com.opensymphony.xwork2.ActionSupport;

@SuppressWarnings("serial")
public class MiscellaneousModelDrivenAction extends ActionSupport implements
        ServletRequestAware {
    private HttpServletRequest request;
    ......
    @Override
    public String execute() throws Exception {
        //实现ServletRequestAware接口，Struts自动注入的request
        Cookie[] cookies = this.request.getCookies();
        for(Cookie ck : cookies){
            System.out.print("cookie:" + ck.getName());
            System.out.println(" = " + ck.getValue());
        }

        return SUCCESS;
    }
    ......
    @Override
    public void setServletRequest(HttpServletRequest request) {
        this.request = request;
    }
}

 7、动态方法调用

a. Action配置中，由method指定动态调用方法的名称。
<action name="myaction" class="com.tests.MyAction" method="myexecute">
......
</action>

b.在JSP页面中，调用Action时加感叹号指定动态调用方法的名称。
<s:form action="myaction!myexecute" />

c.通配符
<action name="*action" class="com.tests.MyAction" method="{1}">
则请求中helloaction对应到action中的hello()方法，以此类推。


8、异常
    发生异常时，可转到指定的result。由exception-mapping配置

 

<action name="miscellaneous" class="wintys.struts2.miscellaneous.MiscellaneousModelDrivenAction">
    <result name="success">/miscellaneous/output.jsp</result>
    <result name="input">/miscellaneous/input.jsp</result>
    <exception-mapping  exception="wintys.struts2.miscellaneous.NameInvalidException" result="nameInvalid" />
    <result name="nameInvalid">/miscellaneous/nameInvalidException.jsp</result>
</action>

 

也可以配置全局exception mapping

 

<global-exception-mapping>
    <exception-mapping result="nameInvalid" />
</global-exception-mapping>

 

 nameInvalidException.jsp:

<s:property value="exception"/>
<s:property value="exceptionStack" />

 NameInvalidException.java:

package wintys.struts2.miscellaneous;
@SuppressWarnings("serial")
public class NameInvalidException extends Exception {
    public NameInvalidException(String message) {
        super(message);
    }
}

 9、详细代码

/StrutsHelloWorld/WebRoot/miscellaneous/input.jsp:

 

<%@ page language="java"  contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>Input</title>
  </head>
  <body>
     <s:actionerror/>
     
    <s:form action="miscellaneous" method="post" theme="simple" namespace="/mystruts">
        <s:token name="mytoken"/>
        
        用户名:<s:textfield name="name" />
        <s:fielderror >
            <s:param>name</s:param>
        </s:fielderror>
        <br />
        
        
        密码:<s:textfield name="password"/>
        <s:fielderror >
            <s:param>password</s:param>
        </s:fielderror>
        <br />
        
        <s:submit name="提  交" />
    </s:form>
    
    <hr />
    动态方法调用方法二:    miscellaneous!myexecute
    <s:form action="miscellaneous!myexecute" namespace="/mystruts">
        <s:token name="mytoken"/>
        <s:hidden name="name" value="test" />
        <s:hidden name="password" value="test" />
        <s:submit name="提交执行myexecute() " />
    </s:form>
  </body>
</html>

 /StrutsHelloWorld/WebRoot/miscellaneous/output.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>Output</title>
  </head>
  <body>
      提交结果:<br/>
    用户名:<s:property value="name"/> <br />
    密码:<s:property value="password"/> <br />
    <hr />
    ${request.info}
    ${cookie.mycookie.value }
  </body>
</html>

 /StrutsHelloWorld/src/wintys/struts2/miscellaneous/MiscellaneousModelDrivenAction.java:

 

package wintys.struts2.miscellaneous;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.ServletRequestAware;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
/**
 * Struts2深入探索
 * @author Winty ([e-mail])
 * @version 2009-8-26
 * @see http://wintys.blogjava.net
 */
@SuppressWarnings("serial")
public class MiscellaneousModelDrivenAction extends ActionSupport implements
        ModelDriven<User> , ServletRequestAware {
    
    private User user = new User();
    private HttpServletRequest request;
    
    @Override
    public User getModel() {
        return user;
    }
    
    @Override
    public String execute() throws Exception {
        System.out.println("this is model driven action");
        
        if(user.getName().equals("admin")){
            throw new NameInvalidException("name 'admin' is invalid");
        }
        
        //ActionContext.put相当于HttpServletRequest.setAttribute()
        ActionContext context = ActionContext.getContext();
        context.put("info", "this is ActionContext value");
        
        //ServletActionContext.getResponse得到Response对象
        Cookie cookie = new Cookie("mycookie" , "10000");
        HttpServletResponse response = ServletActionContext.getResponse();
        response.addCookie(cookie);
        
        //实现ServletRequestAware接口，Struts自动注入的request
        Cookie[] cookies = this.request.getCookies();
        for(Cookie ck : cookies){
            System.out.print("cookie:" + ck.getName());
            System.out.println(" = " + ck.getValue());
        }

        return SUCCESS;
    }
    
    public String myexecute()throws Exception{
        System.out.println("myexecute()");
        
        return SUCCESS;
    }
    
    @Override
    public void validate() {
        if(user.getName() == null || user.getName().equals("")){
            this.addFieldError("name", "invalid name");
        }
    }

    @Override
    public void setServletRequest(HttpServletRequest request) {
        this.request = request;
    }
}

 

 

/src/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>  
    <package name="MyStruts" extends="struts-default" namespace="/mystruts">
        <!-- Struts2深入探索 -->
        <action name="miscellaneous" class="wintys.struts2.miscellaneous.MiscellaneousModelDrivenAction">
            <result name="success">/miscellaneous/output.jsp</result>
            <result name="input">/miscellaneous/input.jsp</result>
            <exception-mapping  exception="wintys.struts2.miscellaneous.NameInvalidException" result="nameInvalid" />
            <result name="nameInvalid">/miscellaneous/nameInvalidException.jsp</result>
            <result name="invalid.token" >/miscellaneous/input.jsp</result>
            <interceptor-ref name="token" />
            <interceptor-ref name="defaultStack" />
        </action>
    </package>
</struts>

 [参考资料]:

    [1]《浪曦视频之Struts2应用开发系列》
    [2] No configuration found for the specified action : http://javasunnyboy.javaeye.com/blog/254753

 

 

 

 

 

该篇BOLG 摘自  http://www.blogjava.net/wintys/archive/2009/08/29/struts_helloworld_miscellaneous.html

 

 

感谢博主的分享. 觉得很实用就全文摘抄下来了..呵呵~~