Struts2入门

Posted 2020-09-21 星辰大海

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结构：

HelloWorldAction.java

package com.struts2.test;

public class HelloWorldAction {
       private String name;

       public String execute() throws Exception {
          return "success";
       }
       
       public String getName() {
          return name;
       }

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

web.xml提供任何Web应用程序的入口点:

<display-name>Struts 2</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>//不写，默认为index.jsp
</welcome-file-list>

<?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">
    <display-name></display-name>

    <!-- Struts2配置 -->
    <filter>
        <filter-name>struts2</filter-name>
        <!-- Filter的实现类 和struts2.5以前的可能有所不同 -->
        <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

index.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Hello World</title>
</head>
<body>
     <h1>Hello World From Struts2</h1>
   <form action="hello">
      <label for="name">Please enter your name</label><br/>
      <input type="text" name="name"/>
      <input type="submit" value="Say Hello"/>
   </form>
</body>
</html>

helloWorld.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
   <%@ taglib prefix="s" uri="/struts-tags"%>
   <!--  taglib指令告诉Servlet容器中，这个页面将使用Struts2标签，这些标签之前，
    将通过s:property标签中显示的动作类的属性名称>HelloWorldAction类的getName()方法返回的值。 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Hello World</title>
</head>
<body>
    Hello World, <s:property value="name"/>
</body>
</html>

struts.xml：

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <package name="struts2" namespace="/" extends="struts-default">
        <!-- <action name="index">
            <result >/index.jsp</result>
         </action> -->
        //如果不带参数的方法不指定，则默认行为是使用execute()方法
        <action name="hello" class="com.struts2.test.HelloWorldAction">
            <result>/helloWorld.jsp</result>
        </action>
　　　　 <-- more actions can be listed here -->
    </package>

    <-- more packages can be listed here -->
</struts>

struts.xml可以包含多个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>
     <include file="struts1.xml"/>
     <include file="struts2.xml"/>
     <include file="struts3.xml"/>
</struts>

logging.properties：

org.apache.catalina.core.ContainerBase.[Catalina].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].handlers = \\java.util.logging.ConsoleHandler

浏览器访问http://localhost:8080/Struts2/

点击say hello 跳转：

-------------------------------完毕---------------------------------------

结构：

accessDenied.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Access Denied</title>
</head>
<body>
    <h1>您没有权限查看此页</h1>
</body>
</html>

HelloWorldAction.java也可以extends ActionSupport

package com.struts2.test;

import com.opensymphony.xwork2.ActionSupport;

public class HelloWorldAction extends ActionSupport {
       /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private String name;

       public String execute() throws Exception {
           if ("成功".equals(name))
              {
                 return SUCCESS;
              }else{
                 return ERROR;  
              }
       }
       
       public String getName() {
          return name;
       }

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

我们可以使用字符串常量SUCCESS、ERROR

struts.xml：如果不带参数的方法不指定，则默认行为是使用execute()方法

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.devMode" value="true" />
      <package name="helloworld" namespace="/" extends="struts-default">
         <action name="hello" 
            class="com.struts2.test.HelloWorldAction" method="execute">
            <result name="success">/helloWorld.jsp</result>
            <result name="error">/accessDenied.jsp</result>
         </action>
      </package>
</struts>

http://localhost:8080/Struts2/index.jsp

点击say hello:

------------------------完毕----------------------------------------

结构：

拦截器

AbstractInterceptor类可以扩展。这提供了一个默认的无操作实现 init() 和destroy()方法。

MyInterceptor.java：

package com.struts2.test;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

public class MyInterceptor extends AbstractInterceptor {

   /**
     * 
     */
    private static final long serialVersionUID = 1L;

public String intercept(ActionInvocation invocation)throws Exception{

      //预处理
      System.out.println("预处理");

      //调用动作或下一个拦截器
      String result = invocation.invoke();

      //后期处理
      System.out.println("后期处理");

      return result;

   }
}

HelloWorldAction.java：

package com.struts2.test;

import com.opensymphony.xwork2.ActionSupport;

public class HelloWorldAction extends ActionSupport {
       /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private String name;

       public String execute() throws Exception {
           System.out.println("进入HelloWorldAction....");
           if ("成功".equals(name))
              {
                 return SUCCESS;
              }else{
                 return ERROR;  
              }
       }
       
       public String getName() {
          return name;
       }

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

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">
    <display-name>Struts2</display-name>
    <welcome-file-list>
      <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <!-- Struts2配置 -->
    <filter>
        <filter-name>struts2</filter-name>
        <!-- Filter的实现类 和struts2.5以前的不同 -->
        <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

http://localhost:8080/Struts2/index.jsp

点击say hello:

控制台：

----------------------完毕-------------------------------------

结构：

FreeMaker视图技术，用于生成输出。不依赖于使用JSP作为视图技术。

hello.fm：

hello  ${name} !

struts.xml：

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.devMode" value="true" />
   <package name="helloworld" extends="struts-default">

      <action name="hello" 
         class="com.struts2.test.HelloWorldAction"
         method="execute">
         <result name="success" type="freemarker">
            <param name="location">/hello.fm</param>
         </result>
      </action>
      
   </package>
</struts>

http://localhost:8080/Struts2/index.jsp

点击say hello

----------------------------------完毕-------------------------------

分发调度RequestDispatcher.forward()

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.devMode" value="true" />
    <package name="helloworld" extends="struts-default">

        <action name="hello" class="com.struts2.test.HelloWorldAction"
            method="execute">
            <result name="success" type="dispatcher">
                <param name="location">
                    /helloWorld.jsp
                </param>
            </result>
        </action>

    </package>
</struts>

----------------------------------完毕-------------------------------

重定向 response.sendRedirect()

struts.xml：

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.devMode" value="true" />
    <package name="helloworld" extends="struts-default">

        <action name="hello" class="com.struts2.test.HelloWorldAction"
            method="execute">
            <result name="success" type="redirect">
                <param name="location">
                    /accessDenied.jsp
                </param>
            </result>
        </action>
    </package>
</struts>

----------------------------------完毕-------------------------------

OGNL对象图导航语言用于引用和操作数据的值栈、数据传输和类型转换。

值栈/OGNL：

OGNL根据上下文和Struts建立一个ActionContext地图：

application - 应用程序范围内的变量
session - 会话范围的变量
root / value stack -所有操作变量都存储在这里
request - 请求范围的变量
parameters - 请求参数
atributes - 存储的属性页面，请求，会话和应用范围

值栈中的对象始终可用，值栈中的对象可以直接引用.

创建动作:访问值栈

HelloWorldAction.java:

package com.struts2.test;

import java.util.*; 

import com.opensymphony.xwork2.util.ValueStack;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class HelloWorldAction extends ActionSupport{
   /**
     * 
     */
    private static final long serialVersionUID = 1L;
private String name;

   public String execute() throws Exception {
      ValueStack stack = ActionContext.getContext().getValueStack();
      Map<String, Object> context = new HashMap<String, Object>();

      context.put("key1", new String("值1")); 
      context.put("key2", new String("值2"));
      stack.push(context);

      System.out.println("Size of the valueStack: " + stack.size());
      return "success";
   }  
　　//使用<s:property>标签访问值
   public String getName() {
      return name;
   }

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

index.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Hello World</title>
</head>
<body>
     <h1>Hello World From Struts2</h1>
   <form action="hello">
      <label for="name">请输入您的姓名</label><br/>
      <input type="text" name="name"/>
      <input type="submit" value="Say Hello"/>
   </form>
</body>
</html>

struts.xml:

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE struts PUBLIC  
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"  
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.devMode" value="true" />
   <package name="helloworld" extends="struts-default">
      <action name="hello" class="com.struts2.test.HelloWorldAction" method="execute">
         <result name="success">/helloWorld.jsp</result>
      </action>
   </package>
</struts>

helloWorld.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"《Java从入门到放弃》入门篇：Struts2的基本数据传递方式
 struts2快速入门
 struts2的使用入门
 《Java从入门到放弃》入门篇：Struts2的常用验证方式
 《Java从入门到放弃》入门篇：Struts2的常用验证方式
 Struts2第一个入门案例

Struts2入门

拦截器

FreeMaker视图技术，用于生成输出。不依赖于使用JSP作为视图技术。

分发调度RequestDispatcher.forward()

重定向 response.sendRedirect()

OGNL对象图导航语言 用于引用和操作数据的值栈、数据传输和类型转换。

值栈/OGNL：

创建动作:访问值栈

OGNL对象图导航语言用于引用和操作数据的值栈、数据传输和类型转换。