02 Struts2框架----学习笔记2(了解一下，已过时)

1.*号通配符优化struts.xml代码

创建一个UserAction的动作类

package action;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport{

    //添加用户
    public String add(){
        return SUCCESS;
    }
    //删除用户
    public String delete(){
        return SUCCESS;
    }
    //更新用户
    public String update(){
        return SUCCESS;
    }

    //查找用户
    public String find(){
        return SUCCESS;
    }

}

Struts.xml文件配置

<!--第一种配置方式-->
    <!--<package name="p2" extends="struts-default">
        <action name="add" class="action.UserAction" method="add">
            <result name="success">/add.jsp</result>
        </action>

        <action name="delete" class="action.UserAction" method="delete">
            <result name="success">/delete.jsp</result>
        </action>

        <action name="find" class="action.UserAction" method="find">
            <result name="success">/find.jsp</result>
        </action>

        <action name="update" class="action.UserAction" method="update">
            <result name="success">/update.jsp</result>
        </action>
    </package>-->

    <!--采用通配符的方式-->
    <!-- 动作访问之通配符
           * ：这里是一个*-->
    <package name="p2" extends="struts-default">
        <action name="*" class="action.UserAction" method="{1}">
            <result name="success">/{1}.jsp</result>
        </action>
    </package>

2.Struts.xml配置文件中的result元素的type取值的四种类型

chain的配置实例：

<1>利用chain转发到同一个包下的不同action

<package name="p3" extends="struts-default">
        <action name="hello1" class="action.HelloAction" method="sayHello">
            <result name="success" type="chain">hello2</result>
        </action>

        <action name="hello2" class="action.HelloAction2" method="sayHello2">
            <result name="success">/hello2.jsp</result>
        </action>
    </package>

效果图：

<2>利用chain转发到不同包下的不同action

<package name="p3" extends="struts-default">
        <action name="hello1" class="action.HelloAction" method="sayHello">
            <result name="success" type="chain">hello3</result>
        </action>

        <action name="hello2" class="action.HelloAction2" method="sayHello2">
            <result name="success">/hello2.jsp</result>
        </action>
    </package>

    <package name="p4" extends="struts-default">

        <action name="hello3" class="action.HelloAction3" method="sayHello3">
            <result name="success">/hello3.jsp</result>
        </action>
    </package>

注意：若加上namespace属性,则struts.xml文件的配置应修改为：

<package name="p3" extends="struts-default" namespace="/n3">
        <action name="hello1" class="action.HelloAction" method="sayHello">
            <result name="success" type="chain">
                <param name="namespace">/n4</param>
                <param name="actionName">hello3</param>
            </result>
        </action>

        <action name="hello2" class="action.HelloAction2" method="sayHello2">
            <result name="success">/hello2.jsp</result>
        </action>
    </package>

    <package name="p4" extends="struts-default" namespace="/n4">

        <action name="hello3" class="action.HelloAction3" method="sayHello3">
            <result name="success">/hello3.jsp</result>
        </action>
    </package>

效果图：

3.动作类中的servlet api访问

通过ServletActionContext获取获取servlet 的api

package action;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class TestAction extends ActionSupport{

    public String test(){
        //获取servlet 的api方式
        //第一种方式：通过ServletActionContext
        //1.response
        HttpServletResponse response = ServletActionContext.getResponse();

        //2.request
        HttpServletRequest request = ServletActionContext.getRequest();

        //3.session
        HttpSession session =  request.getSession();

        //4.application【ServletContext】
        ServletContext application = ServletActionContext.getServletContext();

        //NONE不跳转，也就是不用找result标签
        return NONE;
    }
}

4.Action接收请求参数的方式

(1)通过request对象

　　　　　//获取请求参数
        //第一种方法：通过request对象
        HttpServletRequest request =  ServletActionContext.getRequest();
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        System.out.println(username);
        System.out.println(password);

(2)第2种方式：通过属性的set注入

package action;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.xml.ws.RequestWrapper;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction extends ActionSupport{

    private String username;
    private String password;

    public void setUsername(String username) {
        System.out.println("setUsername");
        this.username = username;
    }

    public void setPassword(String password) {
        System.out.println("setPassword");
        this.password = password;
    }

    public String login(){

        //获取请求参数
        /*//第一种方法：通过request对象
        HttpServletRequest request =  ServletActionContext.getRequest();
        String username = request.getParameter("username");
        String password = request.getParameter("password");*/

        System.out.println(username);
        System.out.println(password);

        //第二种方式：通过属性的set注入

        //NONE不跳转，也就是不用找result标签
        return NONE;
    }
}

(3)第3种方式:通过模型驱动(最常用)

创建一个model---->User

package model;

public class User {

    private String username;
    private String password;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    @Override
    public String toString() {
        return "User [username=" + username + ", password=" + password + "]";
    }

}

动作类代码：

package action;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.xml.ws.RequestWrapper;

import com.opensymphony.xwork2.ModelDriven;
import model.User;
import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction extends ActionSupport implements ModelDriven<User> {

    private User user = new User();
    @Override
    public User getModel() {
        // TODO Auto-generated method stub
        return user;
    }

    public String login(){

        //获取请求参数
        /**
         * 第三种方式: 通过模型驱动【最常用】
         * 实现步骤：
         * 1.在action里实现一个模型驱动接口
         * 2.提供一个模型属性，并一定要赋值
         * 通过这种方式，在jsp页面中就不用写user.
         *
         * 这是模型驱动的原理是因为有个模型驱动的拦截器在处理
         * 这个类就com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor
         */
        System.out.println(user);

        //NONE不跳转，也就是不用找result标签
        return NONE;
    }
}

控制台输出：