struts2总结

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1：环境搭建（helloworld）

1: 下载struts2 包（2.1.8.1）：
    struts-2.1.8.1-all：下面有四个子包apps,docs,lib,src.
2: struts2jar包：
    从struts-2.1.8.1-all\struts-2.1.8.1\apps\struts2-blank-2.1.8.1\WEB-INF\lib中复制所有jar文件，它是最小的jar文件集合。
3：struts2参考手册的使用：
    struts-2.1.8.1-all/struts-2.1.8.1/docs/docs/guides.html
4：修改web.xml:
     打开struts-2.1.8.1-all/struts-2.1.8.1/docs/docs/webxml.html文件，把如下内容写入web.xml.

<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>
5:建立struts.xml文件从struts-2.1.8.1-all\struts-2.1.8.1\apps\struts2-blank-2.1.8.1\WEB-INF\classes把struts.xml文件复制到项目的src目录下。修改struts.xml如下：<?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>    <!-- Add packages here -->    <constant name="struts.devMode" value="true" />     <package name="default" namespace="/" extends="struts-default">        <action name="hello">            <result>                /hello.jsp            </result>        </action>    </package></struts>
6：在webroot下新建一个hello.jsp文件。7：项目发布，在地址栏输入http://localhost:端口名/项目名/hello.action，就可以看到效果了。

2：Struts2 Action(一)

什么是Struts2 Action呢？

实现了
public String execute() throws Exception;
的任何一个java类都可以被认为是Struts2 Action。

注意点：

     1：方法名默认为execute，也可以自定义方法名。

     2：返回值应该为：success,none,error,input和login；

Struts2 Action的实现方法？(三种)

1：
public class IndexAction1 {
    public String execute(){
        return "success";
    }

}
2：
import com.opensymphony.xwork2.Action;

public class IndexAction2 implements Action{
    public String execute(){
        return SUCCESS;
    }

}
3：
import com.opensymphony.xwork2.ActionSupport;

public class IndexAction3 extends ActionSupport {
    private static final long serialVersionUID = 1L;
    @Override
    public String execute(){
        return ERROR;
    }

}
请参考：com.opensymphony.xwork2.Action接口，com.opensymphony.xwork2.ActionSupport类。
        Action接口定义了Struts2 Action应该实现的方法和5个字符串常量作为方法的返回值。
        ActionSupport类是Struts2提供的一个具有基本实现的父类，方便用户的使用。

视图层的跳转

在struts-core jar包中打开struts-default.xml文件，它是一个struts2的默认配置文件。在里面可以找到：

<result-types>
            <result-type name="chain" class="com.opensymphony.xwork2.ActionChainResult"/>
            <result-type name="dispatcher" class="org.apache.struts2.dispatcher.ServletDispatcherResult" default="true"/>
            <result-type name="freemarker" class="org.apache.struts2.views.freemarker.FreemarkerResult"/>
            <result-type name="httpheader" class="org.apache.struts2.dispatcher.HttpHeaderResult"/>
            <result-type name="redirect" class="org.apache.struts2.dispatcher.ServletRedirectResult"/>
            <result-type name="redirectAction" class="org.apache.struts2.dispatcher.ServletActionRedirectResult"/>
            <result-type name="stream" class="org.apache.struts2.dispatcher.StreamResult"/>
            <result-type name="velocity" class="org.apache.struts2.dispatcher.VelocityResult"/>
            <result-type name="xslt" class="org.apache.struts2.views.xslt.XSLTResult"/>
            <result-type name="plainText" class="org.apache.struts2.dispatcher.PlainTextResult" />
</result-types>
它说明了向视图层跳转时有10种方式：

    默认方式为dispatcher，不写时就代表默认方式;
    redirectAction:Struts2 Action的跳转；
    redirect: 与response.sendRedirect()相同；
    dispatcher：与 RequestDispatcher    forward(ServletRequest request,ServletResponse response)相同；

Struts2 Action方法的调用（三种）：

1：在<action />中没有定义method属性，表示调用当前Action的execute();

<action name="index3" class="com.action.IndexAction3">
            <result name="error">
                /hello3.jsp
            </result>
</action>

2: Wildcards
    As an application grows in size, so will the number of action mappings. Wildcards can be used to combine similar mappings into one more generic mapping.

<action name="index1*" class="com.action.IndexAction1" method="{1}" >
            <result name="success" type="redirectAction" >
            index3
            </result>
</action>

method中的1代表name中的第一个*；

3：Dynamic Method Invocation

Dynamic Method Invocation (DMI) will use the string following a "!" character in an action name as the name of a method to invoke (instead ofexecute). A reference to "Category!create.action", says to use the "Category" action mapping, but call thecreate method instead.

<action name="index2!*" class="com.action.IndexAction2" method="{1}">
            <result name="success">
                /hello2.jsp
            </result>
</action>

method中的1代表name中的第一个*；

实例：
package com.action;

public class IndexAction1 {
    public String msg(){
        return "success";
    }

}

---

package com.action;

import com.opensymphony.xwork2.Action;

public class IndexAction2 implements Action{
    public String execute(){
        return SUCCESS;
    }
    public String succ(){
        return SUCCESS;
    }

}
---

package com.action;

import com.opensymphony.xwork2.ActionSupport;

public class IndexAction3 extends ActionSupport {
    @Override
    public String execute(){

        return ERROR;
    }

}
---

<?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.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="true" />
    <package name="default" namespace="/" extends="struts-default">
        <action name="index1*" class="com.action.IndexAction1" method="{1}" >
            <result name="success" type="redirectAction" >
            index3
            </result>
        </action>
        <action name="index2!*" class="com.action.IndexAction2" method="{1}">
            <result name="success">
                /hello2.jsp
            </result>
        </action>
        <action name="index3" class="com.action.IndexAction3">
            <result name="error">
                /hello3.jsp
            </result>
        </action>
    </package>
    

</struts>
---

测试：
分别用以下URL，注意观察和思考：
http://localhost:8080/struts2_0200_action/index3
http://localhost:8080/struts2_0200_action/index2!succ
http://localhost:8080/struts2_0200_action/index2
http://localhost:8080/struts2_0200_action/index1msg
注意：
<result name="error">
/hello3.jsp
</result>
name代表Action方法的返回值,缺省代表success；
type代表Action向视图跳转时的跳转类型,缺省代表plainText。

3：Struts2 Action(二)action 获取参数的三种方法

一：Action获取参数的方法（3种）
1：ModelDriven方式：

package com.action;

import com.domain.User;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.ModelDriven;

public class UserAction1 extends ActionSupport implements ModelDriven<User>

{

private User user = new User();

public String add()

{

System.out.println(user.getName());

System.out.println(user.getAge());

return "success";

}

public User getModel()

{

return user;

}

2：Domain Model方式：

package com.action;

import com.domain.User;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction2 extends ActionSupport

{

private User user ;

public String add()

{

System.out.println(user.getName());

System.out.println(user.getAge());

return "success";

}

public User getUser()

{

return user;

}

public void setUser(User user)

{

this.user = user;

}

3：Parameters方式：

package com.action;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction3 extends ActionSupport

{

private String name;

private String age;

public String add()

{

System.out.println(name);

System.out.println(age);

return "success";

}

public String getName()

{

return name;

}

public void setName(String name)

{

this.name = name;

}

public String getAge()

{

return age;

}

public void setAge(String age)

{

this.age = age;

}

User.java

package com.domain;

public class User

{

private String name;

private String age;

public String getName()

{

return name;

}

public void setName(String name)

{

this.name = name;

}

public String getAge()

{

return age;

}

public void setAge(String age)

{

this.age = age;

}

4：Struts2 Action(三) 访问web元素的四种方式

1： Map IoC 方式

package com.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.ActionSupport;

public class UserAction1 extends ActionSupport implements RequestAware,SessionAware,ApplicationAware {
    private Map<String, Object> request;
    private Map<String, Object> session;
    private Map<String, Object> application;
    public String add(){
        request.put("r1", "r1");
        session.put("s1", "s1");
        application.put("a1", "a1");
        return "success";
    }
    public void setRequest(Map<String, Object> request) {
        this.request=request;
    }
    public void setSession(Map<String, Object> session) {
        this.session=session;
    }
    public void setApplication(Map<String, Object> application) {
        this.application=application;
    }
}

2： Map 依赖容器方式:
package com.action;

import java.util.Map;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class UserAction2 extends ActionSupport {
    private Map<String, Object> request;
    private Map<String, Object> session;
    private Map<String, Object> application;
    public UserAction2() {
        ActionContext context = ActionContext.getContext();
        request=(Map<String, Object>)context.get("request");
        session=context.getSession();
        application=context.getApplication();
    }
    public String add(){
        request.put("r2", "r2");
        session.put("s2", "s2");
        application.put("a2", "a2");
        return "success";
    }
}

3： Servlet IoC 方式：
package com.action;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.struts2.interceptor.ServletRequestAware;
import com.opensymphony.xwork2.ActionSupport;

public class UserAction3 extends ActionSupport implements ServletRequestAware {
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    public String add() {
        request.setAttribute("r3", "r3");
        session.setAttribute("s3", "s3");
        application.setAttribute("a3", "a3");
        return "success";
    }
    public void setServletRequest(HttpServletRequest request) {
        this.request=request;
        this.session=request.getSession();
        this.application=session.getServletContext();
    }
}

4： Servlet 依赖容器方式:

package com.action;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction4 extends ActionSupport {
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    public UserAction4() {
        request = ServletActionContext.getRequest();
        session=request.getSession();
        application=session.getServletContext();
    }
    public String add(){
        request.setAttribute("r4", "r4");
        session.setAttribute("s4", "s4");
        application.setAttribute("a4", "a4");
        return "success";
    }
}