struts学习(四)—属性封装、模型驱动封装和表达式封装

xiaoxiao2021-03-25 83

本文学习内容来自传智博客struts教程。

1.属性封装

作用：直接把表单提交属性封装到action的属性里面步骤： (1)在action中声明成员变量，变量名称和表单输入项的名称一样 (2)生成变量的set方法。缺点：数据只是放在属性中，并没有放到对象中去。

(1)action类：

package data; import com.opensymphony.xwork2.ActionSupport; public class DataDemo1Action extends ActionSupport { private String username; private String password; private String address; public String execute() throws Exception { System.out.println("username:"+username+"password:"+password+"address:"+address); return NONE; } 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; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }

(2)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> <package name="demo1" extends="struts-default" namespace="/"> <action name="book" class="action.BookAction">  <result name="success" type="chain">orders</result> </action> <action name="orders" class="action.OrdersAction"> <result name="success">/HelloOrder.jsp</result> </action> </package> <package name="demo2" extends="struts-default" namespace="/"> <action name="data1" class="data.DataDemo1Action"></action> </package> </struts>

(3)data1.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <form action="${pageContext.request.contextPath}/data1.action" method="post"> username:<input type="text" name="username"/> <br/> password:<input type="text" name="password"/> <br/> address:<input type="text" name="address"/> <br/> <input type="submit" value="submit"/> </form> </body> </html>

2.模型驱动封装

作用：使用模型驱动封装，可以直接把表单属性封装到实体类对象里面实现步骤： (1)action实现接口ModelDriven (2)实现接口里面的getModel()方法把创建对象返回 (3)在action里面创建实体类对象要求：表单输入项的name属性值和实体类属性名称一样。

(1)action类：

package data; import com.opensymphony.xwork2.ActionSupport; import com.opensymphony.xwork2.ModelDriven; import entity.User; public class DataDemo2Action extends ActionSupport implements ModelDriven<User> { //创建对象 private User user = new User(); public String execute() throws Exception { System.out.println(user); return NONE; } @Override public User getModel() { return user; } }

(2)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> <package name="demo1" extends="struts-default" namespace="/"> <action name="book" class="action.BookAction">  <result name="success" type="chain">orders</result> </action> <action name="orders" class="action.OrdersAction"> <result name="success">/HelloOrder.jsp</result> </action> </package> <package name="demo2" extends="struts-default" namespace="/"> <action name="data2" class="data.DataDemo2Action"></action> </package> </struts>

(3)data2.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <form action="${pageContext.request.contextPath}/data2.action" method="post"> username:<input type="text" name="username"/> <br/> password:<input type="text" name="password"/> <br/> address:<input type="text" name="address"/> <br/> <input type="submit" value="submit"/> </form> </body> </html>

(4)实体类：

package entity; public class User { private String username; private String password; private String address; 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; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }

3.表达式封装

作用使用表达式封装可以将表单数据封装到实体类里面步骤 1.在action中声明实体类 2.生成实体类变量的set方法 3.在表单输入项的name属性值里面写表达式形式。

(1)action类

package data; import com.opensymphony.xwork2.ActionSupport; import entity.Book; import entity.User; public class DataDemo3Action extends ActionSupport { private User user; private Book book; public Book getBook() { return book; } public void setBook(Book book) { this.book = book; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } @Override public String execute() throws Exception { System.out.println(user); System.out.println(book); return NONE; } }

(2)book实体类

package entity; public class Book { private String bookname; public String getBookname() { return bookname; } public void setBookname(String bookname) { this.bookname = bookname; } }

(3)dat3.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <form action="${pageContext.request.contextPath}/data3.action" method="post"> username:<input type="text" name="user.username" /> <br/> password:<input type="text" name="user.password" /> <br/> address:<input type="text" name="user.address" /> <br/> bookname:<input type="text" name="book.bookname"/> <br/> <input type="submit" value="submit" /> </form> </body> </html>

(4)struts文件

<?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> <package name="demo1" extends="struts-default" namespace="/"> <action name="book" class="action.BookAction">  <result name="success" type="chain">orders</result> </action> <action name="orders" class="action.OrdersAction"> <result name="success">/HelloOrder.jsp</result> </action> </package> <package name="demo2" extends="struts-default" namespace="/"> <action name="data3" class="data.DataDemo3Action"></action> </package> </struts>

4.代码总体架构

4.使用以上封装要注意的问题

(1)同一个action中，不能同时使用属性封装和模型驱动封装获取同一个表单数据。如果同时使用，则框架只会使用模型驱动。

(2)模型驱动与表达式封装的不同： 1.使用模型驱动只能把数据封装到一个实体类对象里面。在一个action里面不能把模型驱动封装到不同的实体类对象里面。 2.表达式封装可以把数据封装到不同的对象中去。

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