Struts2学习笔记

Struts2学习笔记

1.官网下载包

URL:http://struts.apache.org/
解压:/apps/struts2-blank.war
拷贝：struts.xml+web.xml+jar

2.struts.xml尖括号提示：

a.解压struts2-core-2.3.15.1.jar
b.windows--preferences--catalog--add:
  解压文件中的dtd
  URL
  http://struts.apache.org/dtds/struts-2.3.dtd

3.工作流程图


4.常量配置

struts.xml配置：
    <constant name="struts.i18n.encoding" value="UTF-8"/>
该常量会覆盖struts2-core-2.3.15.jar包中/org.apache.struts2.default.properties中的值

5.jsp引入的标签s

<%@ taglib prefix="s" uri="/struts-tags" %>
这个uri对应该struts2-core-2.3.15.jar包中/META-INF/struts-tags.tld
该文件中：
  <display-name>Struts Tags</display-name>
  <tlib-version>2.3</tlib-version>
  <short-name>s</short-name>
  <uri>/struts-tags</uri>
  处理类：<tag-class>org.apache.struts2.views.jsp.ActionTag</tag-class>
这个uri和此处的uri对应

5.struts.xml以及其他XML配置

<?xml version="1.0" encoding="UTF-8" ?>
1.struts.xml:
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN" "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <!-- true:开发模式，修改XML配置文件不用重启服务 -->
    <constant name="struts.devMode" value="false" />
    <constant name="struts.i18n.encoding" value="UTF-8"/>
    <constant name="struts.enable.DynamicMethodInvocation" value="false" />

    <package name="default" namespace="/default" extends="struts-default">
        <!-- 公共的跳转页面,所有Action都可以调用该result -->
        <global-results>
            <result name="error">/views/error.jsp</result>
        </global-results>
        
        <!-- 异常错误处理页面 -->
        <global-exception-mappings>
            <exception-mapping exception="java.lang.Exception" result="error"/>
        </global-exception-mappings>
    </package>

	<!-- xml文件列表 -->
	<include file="/default.xml"/>
        <include file="/home.xml"/>
        <include file="/userInfo.xml"/>
</struts>

extends="struts-default":继承了struts2-core-2.3.15.jar包中struts-default.xml的：
result结果集
Interceptor拦截器等


2.userInfo.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="userInfoPackage" namespace="/" extends="default">
        <action name="userInfo_*" class="com.momo.action.UserInfoAction" method="{1}">
            <result name="success">/views/userInfo/userInfo_{1}_success.jsp</result>
            <result name="fail">/views/userInfo/userInfo_{1}_fail.jsp</result>
        </action>
        
        <!-- 服务其跳转：页面 -->
        <action name="dispatcher">
            <result type="dispatcher">/views/userInfo/dispatcher.jsp</result>
        </action>
        <!-- 客户端跳转：页面 -->
        <action name="redirect">
            <result type="redirect">/views/userInfo/redirect.jsp</result>
        </action>
        <!-- 服务器跳转：Action方法 -->
        <action name="chain">
            <result type="chain">
               <!-- 指定要跳转的Action位置 -->
               <param name="namespace">/</param>
               <param name="actionName">dispatcher</param>
            </result>
        </action>
        <!-- 客户端跳转：Action方法 -->
        <action name="redirectAction">
            <result type="redirectAction">redirect</result>
        </action>
    </package>
</struts>

extends="default":可以共用namespace="default"目录中的结果集result

5.struts.xml配置前台UI标签样式

struts.xml:  
  <constant name="struts.ui.theme" value="simple"/><!-- UI标签类型(ajax,simple,xhtml,css_xhtml) -->

jsp:
	    <s:form>
	       <s:fielderror/>
	    </s:form>
html源码样式会采用最简单的，支持本地覆盖struts2-core-2.3.15.jar包中template中的模板也支持自定义模板

5.拦截器执行过程

模拟原理如下：
Main.java
ActionInvocation.java
Interceptor.java
FirstInterceptor.java
SecondInterceptor.java
Action.java

public class Main {
	public static void main(String[] args) {
		new ActionInvocation().invoke();
	}
}

public class ActionInvocation {
	List<Interceptor> interceptors = new ArrayList<Interceptor>();
	int index = -1;
	Action a = new Action();
	
	public ActionInvocation() {
		this.interceptors.add(new FirstInterceptor());
		this.interceptors.add(new SecondInterceptor());
		
	}
	
	public void invoke() {
		index ++;
		if(index >= this.interceptors.size()) {
			a.execute();
		}else {
			
			this.interceptors.get(index).intercept(this);
		}
	}
}

public interface Interceptor {
	public void intercept(ActionInvocation invocation) ;
}

public class FirstInterceptor implements Interceptor {
	public void intercept(ActionInvocation invocation) {
		System.out.println(1);
		invocation.invoke();
		System.out.println(-1);
	}
}

public class SecondInterceptor implements Interceptor {
	public void intercept(ActionInvocation invocation) {
		System.out.println(2);
		invocation.invoke();
		System.out.println(-2);
	}
}

public class Action {
	public void execute() {
		System.out.println("execute!");
	}
}

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