Struts2系列之动作类

编写动作类的三种方式

1.动作类的第一种:普通的javaBean,没有任何继承 POJO(Plan Old Java Object)

Action类:

/**
 * Created by dllo on 17/7/4.
 * 动作类的第一种
 * POJO:Plan Old Java Object
 */
public class DemoAction1 {

    //动作方法:
    public String demo1(){

        return "success";
    }

}

struts.xml

<struts>
 <package name="actions" extends="struts-default">

        <action name="demo1" class="com.wangyjie.struts.actions.DemoAction1" method="demo1">
            <result name="success">/success.jsp</result>
        </action>

    </package>
</struts>

---

2. 动作类第二种 实现Action接口

Action类

/**
 * Created by dllo on 17/7/4.
 * 动作类的第二种
 *
 * 实现Action的接口
 */
public class DemoAction2 implements Action{


    @Override
    public String execute() throws Exception {

        return SUCCESS;
    }
}

struts.xml

 <package name="action2" extends="struts-default">
        <action name="demo2" class="com.wangyjie.struts.actions.DemoAction2" method="execute">
            <result name="success">/success.jsp</result>
        </action>

    </package>

---

3. 动作类第三种:继承ActionSupport[推荐使用]

//Action类

/**
 * Created by dllo on 17/7/4.
 * 动作类的第三种: [推荐使用]
 * 继承于ActionSupport
 */
public class DemoAction3 extends ActionSupport{


    public String www(){

        return ERROR;
    }

}

//struts.xml

  <package name="action3" extends="struts-default">
        <action name="demo3" class="com.wangyjie.struts.actions.DemoAction3" method="www">
            <result name="error">/error.jsp</result>
        </action>
    </package>

---

动作类中的动作方法编写要求

public String XXX(){}

使用通配符配置action

在配置元素时,允许在指定name属性时,使用模式字符串(“*”代表一个或多个字符)

为了防止写一些这样重复性的东西 出现了通配符

  <action name="delete_Customer" class="com.wangyjie.struts.wildcard.CustomerAction" method="deleteCustomer">
            <result name="success">/deleteCustomer.jsp</result>
        </action>

        <action name="edit_Customer" class="com.wangyjie.struts.wildcard.CustomerAction" method="editCustomer">
            <result name="success">/editCustomer.jsp</result>
        </action>

        <action name="query_Customer" class="com.wangyjie.struts.wildcard.CustomerAction" method="queryCustomer">
            <result name="success">/queryCustomer.jsp</result>

 <!--通配符 类似我们之前学过的占位符一样-->

        <action name="*Customer" class="com.wangyjie.struts.wildcard.CustomerAction" method="{1}Customer">
            <result name="success">{1}Customer.jsp</result>
        </action>

        <action name="*_*" class="com.wangyjie.struts.wildcard.{2}Action" method="{1}{2}">
            <result name="success">{1}{2}.jsp</result>
        </action>

---

Action访问ServletAPI

方式一:ServletActionContext

HttpServletRequest request = ServletActionContext.getRequest();

实现ServletRequestAware接口

 private HttpServletRequest request;
//重写方法
    @Override
    public void setServletRequest(HttpServletRequest httpServletRequest) {
        this.request = httpServletRequest;
    }

    public HttpServletRequest getRequest(){
        return request;
    }