struts2传递参数的三种方式

程序员文章站 2022-03-02 22:45:02

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转自https://blog.csdn.net/Manchester117/article/details/51543566

1.普通的传值方式

UserActionForCommonParam类

Action类接收三个参数,分别是id,username,content.




package com.struts.action;







public class UserActionForCommonParam {



    private int id;



    private String username;



    private String content;







    public int getId() {



        return id;



    }







    public void setId(int id) {



        this.id = id;



    }







    public String getUsername() {



        return username;



    }







    public void setUsername(String username) {



        this.username = username;



    }







    public String getContent() {



        return content;



    }







    public void setContent(String content) {



        this.content = content;



    }







    // 从前台页面接收到参数后会在这个方法里打印



    public String addUser() {



        System.out.println("ID: " + this.getId());



        System.out.println("Username: " + this.getUsername());



        System.out.println("Content: " + this.getContent());



        return "success";



    }



}

对应的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.enable.DynamicMethodInvocation" value="true"/>




    <constant name="struts.devMode" value="true"/>




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




        <action name="UserActionForCommonParam" class="com.struts.action.UserActionForCommonParam" method="addUser">




            <result name="success">/UserPage.jsp</result>




        </action>




    </package>




</struts>

前台页面UserPage.jsp




<%@ page contentType="text/html;charset=UTF-8" language="java" %>



<%@ taglib prefix="s" uri="/struts-tags" %>



<html>



<head>



    <title>UserPage</title>




</head>



<body>



    <%--下面的Table用于提交参数(id,username,content)--%>




    <form action="UserActionForCommonParam" method="POST">




        <table border="1">




            <tr>




                <td>ID:</td>




                <td><input type="text" name="id"/></td>




            </tr>




            <tr>




                <td>Username:</td>




                <td><input type="text" name="username"/></td>




            </tr>




            <tr>




                <td>Content:</td>




                <td><input type="text" name="content"/></td>




            </tr>




            <tr>




                <td colspan="2" align="center">




                    <input type="submit" value="提交"/>




                </td>




            </tr>




        </table>




    </form>




    <br/>




    <%--下面的Table用于显示传递回来id,username,content--%>




    <table border="1">




        <tr>




            <td>ID: </td>




            <td><input type="text" value="${id}"/></td>




        </tr>




        <tr>




            <td>Username: </td>




            <td><input type="text" value="${username}"/></td>




        </tr>




        <tr>




            <td>Content: </td>




            <td><input type="text" value="${content}"/></td>




        </tr>




    </table>




    <%--用于查看ValueStack中的传递的值--%>




    <s:debug/>




</body>



</html>

在实践后会发现,如果遇到参数非常多的情况,那么就需要在Action类中写非常多的属性以及对应的get/set方法.所以这种方式不太可取.解决问题的方法必然是封装一个JavaBean.这就用到了Strut2的第二种传值方式--DomainModel

2.DomainModel传值

首先要创建一个存储的JavaBean

User类

把id,username,content封装的到一个User类当中.





package com.struts.model;








public class User {



    private int id;



    private String username;



    private String content;







    public int getId() {



        return id;



    }







    public void setId(int id) {



        this.id = id;



    }







    public String getUsername() {



        return username;



    }







    public void setUsername(String username) {



        this.username = username;



    }







    public String getContent() {



        return content;



    }







    public void setContent(String content) {



        this.content = content;



    }



}

UserActionForDomainModel类





package com.struts.action;








import com.opensymphony.xwork2.ActionSupport;




import com.struts.model.User;








public class UserActionForDomainModel extends ActionSupport{



    private User user;







    public User getUser() {



        return user;



    }







    public void setUser(User user) {



        this.user = user;



    }







    public String addUser() {



        System.out.println("ID: " + user.getId());



        System.out.println("Username: " + user.getUsername());



        System.out.println("Content: " + user.getContent());



        return "success";



    }



}

对应的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.enable.DynamicMethodInvocation" value="true"/>




    <constant name="struts.devMode" value="true"/>




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




        <action name="userForDomainModel" class="com.struts.action.UserActionForDomainModel" method="addUser">




            <result name="success">/UserPage.jsp</result>




        </action>




    </package>




</struts>

前台页面UserPage.jsp




<%@ page contentType="text/html;charset=UTF-8" language="java" %>



<%@ taglib prefix="s" uri="/struts-tags" %>



<html>



<head>



    <title>UserPage</title>




</head>



<body>



    <%--要特别注意的是DomainModel的传值方式必须要使用对象.参数方式进行赋值以及取值--%>




    <form action="userForDomainModel" method="POST">




        <table border="1">




            <tr>




                <td>ID:</td>




                <td><input type="text" name="user.id"/></td>




            </tr>




            <tr>




                <td>Username:</td>




                <td><input type="text" name="user.username"/></td>




            </tr>




            <tr>




                <td>Content:</td>




                <td><input type="text" name="user.content"/></td>




            </tr>




            <tr>




                <td colspan="2" align="center">




                    <input type="submit" value="提交"/>




                </td>




            </tr>




        </table>




    </form>




    <br/>




    <%--下面的Table用于显示传递回来id,username,content--%>




    <table border="1">




        <tr>




            <td>ID: </td>




            <td><input type="text" value="${user.id}"/></td>




        </tr>




        <tr>




            <td>Username: </td>




            <td><input type="text" value="${user.username}"/></td>




        </tr>




        <tr>




            <td>Content: </td>




            <td><input type="text" value="${user.content}"/></td>




        </tr>




    </table>




    <%--用于查看ValueStack中的传递的值--%>




    <s:debug/>




</body>



</html>

实际上User类不需要显式的实例化,struts会自动帮你实例化,但前提条件是,传值时需要使用对象.参数名的方式进行传递.

除了这种传值方式外,struts2还提供另外一种传值方式.

3.ModelDriven传值

依然要创建User的JavaBean

User类





package com.struts.model;








public class User {



    private int id;



    private String username;



    private String content;







    public int getId() {



        return id;



    }







    public void setId(int id) {



        this.id = id;



    }







    public String getUsername() {



        return username;



    }







    public void setUsername(String username) {



        this.username = username;



    }







    public String getContent() {



        return content;



    }







    public void setContent(String content) {



        this.content = content;



    }



}

UserActionForModelDriven类





package com.struts.action;








import com.opensymphony.xwork2.ModelDriven;




import com.struts.model.User;








public class UserActionForModelDriven implements ModelDriven<User>{



    private User user;







    public String addUser() {



        System.out.println("ID: " + user.getId());



        System.out.println("Username: " + user.getUsername());



        System.out.println("Content: " + user.getContent());



        return "success";



    }







    @Override




    public User getModel() {



        if (user == null) {



            user = new User();



        }



        return user;



    }



}

这种方式可以不用在Action类中编写对应的get/set方法,但是需要实例化User类.

前台UserPage.jsp




<%@ page contentType="text/html;charset=UTF-8" language="java" %>



<%@ taglib prefix="s" uri="/struts-tags" %>



<html>



<head>



    <title>UserPage</title>




</head>



<body>



    <form action="userForModelDriven" method="POST">




        <table border="1">




            <tr>




                <td>ID:</td>




                <td><input type="text" name="id"/></td>




            </tr>




            <tr>




                <td>Username:</td>




                <td><input type="text" name="username"/></td>




            </tr>




            <tr>




                <td>Content:</td>




                <td><input type="text" name="content"/></td>




            </tr>




            <tr>




                <td colspan="2" align="center">




                    <input type="submit" value="提交"/>




                </td>




            </tr>




        </table>




    </form>




    <br/>




    <%--下面的Table用于显示传递回来id,username,content--%>




    <table border="1">




        <tr><span id="transmark"></span>




            <td>ID: </td>




            <td><input type="text" value="${id}"/></td>




        </tr>




        <tr>




            <td>Username: </td>




            <td><input type="text" value="${username}"/></td>




        </tr>




        <tr>




            <td>Content: </td>




            <td><input type="text" value="${content}"/></td>




        </tr>




    </table>




    <%--用于查看ValueStack中的传递的值--%>




    <s:debug/>




</body>



</html>

页面还是和普通传值一样.

可以去ValueStack当中观察参数的存储,更透彻的理解Struts2的参数传递.

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