Struts2的4种传值方式：
1.通过request/session等传值
可通过ServletActionContext.getRequest()/getSession()等方法来获得request/session对象，
然后调用其中的setAttribute(),getAttribute(),getParameter()方法来传值。
public class UserAction{ public String addUser() { //通过request int id=ServletActionContext.getRequest().getParameter("id"); String username= ServletActionContext.getRequest().getParameter("username"); //通过session ServletActionContext.getRequest().getSession().getAttribute("username"); //通过session ActionContext.getContext().getSession().getAttribute("username"); System.out.println(username+" "+id); return "success"; } }
2.普通传值，一个javabean,xml配置文件
public class UserAction{ private int id; private String username; 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; } // 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()); return "success"; } }
<?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="UserAction" class="com.struts.action.UserAction" method="addUser"> <result name="success">/UserPage.jsp</result> </action> </package> </struts>
前端页面：
<%@ 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="UserAction" 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> <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> </table> <%--用于查看ValueStack中的传递的值--%> <s:debug/> </body> </html>
3.使用model传值：建立一个model类Uesr来存储数据,一个UserAction要继承ActionSupport来操作，
public class UserAction extends ActionSupport
xml配置，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.比如form表单的输入要写成name=“user.name”
<input type="text" name="user.username"/>
public class User{ private int id; private String username; 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 class UserAction 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()); return "success"; } }
<?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="userAction" class="com.struts.action.UserAction" method="addUser"> <result name="success">/UserPage.jsp</result> </action> </package> </struts>
<%@ 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="userAction" 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 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> </table> <%--用于查看ValueStack中的传递的值--%> <s:debug/> </body> </html>
4.同样是使用model来传值，还是创建一个model类User,UserAction操作类要实现接口：
public class UserAction implements ModelDriven<User>
不同的是在UserAction中可以不用编写对应的get/set方法,但是需要实例化User类.但前端页面form表单的name可以直接写对应User类的属性名
<input type="text" name="username"/>
public class User{ private int id; private String username; 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 class UserAction implements ModelDriven<User>{ private User user; public String addUser() { System.out.println("ID: " + user.getId()); System.out.println("Username: " + user.getUsername()); return "success"; } @Override public User getModel() { if (user == null) { user = new User(); } return user; } }
<%@ 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 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> </table> <%--用于查看ValueStack中的传递的值--%> <s:debug/> </body> </html>
我的座右铭：不会，我可以学；落后，我可以追赶；跌倒，我可以站起来；我一定行。