获取页面数据
1、属性驱动
- 对于属性驱动，我们需要在Action中定义与表单元素对应的所有的属性，因而在Action中会出现很多的getter和setter方法
- 表单 或 URL 中的 参数名称 跟 Action 类中的属性名称一致，即可
- 属性驱动的第一种方式（推荐使用的方式，直接将action做一个model(类似bean结构),就可以得到请求参数.）
index.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
Apache Struts 属性驱动(赞成使用):
注册struts.xml
/WEB-INF/pages/results/register_success.jsp /WEB-INF/pages/results/login_success.jsp Action类
package ecut.results.action;import org.apache.logging.log4j.LogManager;import org.apache.logging.log4j.Logger;import com.opensymphony.xwork2.Action;import ecut.results.entity.Customer;public class RegisterAction implements Action { private static final Logger logger = LogManager.getLogger(); private String username ; private String password ; private String confirm ; private Customer customer ; @Override public String execute() throws Exception { if( customer != null ) { logger.info( "customer username : " + customer.getUsername() ); logger.info( "customer password : " + customer.getPassword() ); logger.info( "customer confirm : " + customer.getConfirm() ); } else { logger.info( "username : " + username ); logger.info( "password : " + password ); logger.info( "confirm : " + confirm ); } return SUCCESS; } public Customer getCustomer() { return customer; } public void setCustomer(Customer customer) { this.customer = customer; } 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 getConfirm() { return confirm; } public void setConfirm(String confirm) { this.confirm = confirm; } }register_success.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
注册成功 注册成功
username: ${ username }
page scope: ${ pageScope.username }
request scope: ${ requestScope.username }
session scope: ${ sessionScope.username }
application scope: ${ applicationScope.username }
customer.username : ${ customer.username }
request scope: ${ requestScope.customer.username }
在同一个请求中因此参数保留在requestScope中
-
属性驱动的第二种方式（反对使用，在action中声明一个model，js不通用）
index.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
Apache Struts 属性驱动(反对使用):
Action中增加customer 的model
2、模块驱动
- 对于模型驱动，使用的Action对象需要实现ModelDriven接口并给定所需要的类型.而在Action中我们只需要定义一个封装所有数据信息的javabean
- 模块驱动的具体实现
index.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
Apache Struts 模型驱动:
Action类
package ecut.results.action;import org.apache.logging.log4j.LogManager;import org.apache.logging.log4j.Logger;import com.opensymphony.xwork2.Action;import com.opensymphony.xwork2.ModelDriven;import ecut.results.entity.Customer;public class LoginAction implements Action , ModelDriven
{ private static final Logger logger = LogManager.getLogger(); private Customer customer ; @Override public String execute() throws Exception { System.out.println( this ); logger.info( "username : " + customer.getUsername() ); logger.info( "password : " + customer.getPassword() ); return SUCCESS; } @Override public Customer getModel() { logger.info( "调用 getModel方法" ); //首先实现接口ModelDriven，其次通过getModel方法告诉Struts将参数封装到那个对象去 if( this.customer == null ) { logger.info( "创建对象" ); this.customer = new Customer(); } return this.customer ; } public Customer getCustomer() { return customer; } public void setCustomer(Customer customer) { this.customer = customer; }} Action类实现ModelDriven接口并覆盖getModel()方法，在Action类中实例化一个model对象，由Struts2提供的拦截器（ParametersInterceptor）去完成数据封装，让getModel方法返回这个对象。getModel()方法在excute()方法执行之前。因为每一次请求，都是一个新的action，所以getModel()方法中的判断语句是多余的，与spring有所不同。
注意：getModel 返回的是Action类中定义的model（this.customer），而不能直接返回 new Customer，excute方法和getModel应该使用的是同一个对象，不然会抛出空指针异常
login_success.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
登录成功 登录成功
customer.username : ${ customer.username }
request scope: ${ requestScope.customer.username }
session scope: ${ sessionScope.customer.username }
访问 Servlet API
1、间接访问（推荐使用的方法）
- 通过ActionContext来访问
ActionContext context = ActionContext.getContext(); Map<String,Object> applicationMap = context.getApplication(); // 这个 Map 集合 ServletCotnext Map<String,Object> sessionMap = context.getSession(); // 这个 Map 集合与 HttpSession HttpParameters params = context.getParameters(); // request parameter
- 测试案例
index.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
Apache Struts 登录( 并将用户信息存储到 Session 中 ):
${ sessionScope.error_message } <%--EL3.0才支持直接调用方法 ${ pageContext.session.removeAttribute( 'error_message' ) } --%> <% session.removeAttribute( "error_message" ) ;%>struts.xml
main /results/index.jsp /WEB-INF/pages/results/login_success.jsp /results/index.jsp Action类
package ecut.results.action;import java.util.Map;import com.opensymphony.xwork2.Action;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ModelDriven;import ecut.results.entity.Customer;public class CustomerAction implements Action , ModelDriven
{ private Customer customer ; @Override public String execute() throws Exception { System.out.println( "execute" ); return SUCCESS; } public String login() throws Exception { System.out.println( "login" ); // 获得 当前正在执行的 Action 的 上下文对象 ActionContext context = ActionContext.getContext(); // 通过 ActionContext 的 getSession 来获得 与 HttpSession 对应的 Map 集合 // 针对这个 Map 的 所有操作 都会立即 "同步" 到 HttpSession 对象中 Map< String , Object > sessionMap = context.getSession(); if( "zhangsanfeng".equals( customer.getUsername() ) && "hello2017".equals( customer.getPassword() ) ){ sessionMap.put( "customer" , this.customer ) ; // 由拦截器去完成这个操作session.setAttribute( "customer" , this.customer ); return SUCCESS; } else { sessionMap.put( "error_message" , "用户名或密码错误" ); return INPUT; } } public String logout() throws Exception { System.out.println( "logout" ); ActionContext context = ActionContext.getContext(); Map< String , Object > sessionMap = context.getSession(); sessionMap.remove( "customer" ) ; // session.removeAttribute( "customer" ); return SUCCESS; } @Override public Customer getModel() { if( this.customer == null ){ this.customer = new Customer(); } return this.customer; } public Customer getCustomer() { return customer; } public void setCustomer(Customer customer) { this.customer = customer; } } login_success.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
登录成功 登录成功
customer.username : ${ customer.username }
request scope: ${ requestScope.customer.username }
session scope: ${ sessionScope.customer.username }
注销logout_success.jsp
<%@ page language = "java" pageEncoding = "UTF-8" %> <%@ page contentType = "text/html; charset= UTF-8"%>
注销成功 注销成功
2、直接访问（不推荐使用，如果已经使用了 Struts 框架，则应该优先考虑使用 Struts 而不是使用 Servlet ）
- 实现接口并提供 setter 方法（与servlet API 耦合大).）
- 通过 ServletActionContext 类的静态方法
org.apache.struts2.ServletActionContext.getResponse() org.apache.struts2.ServletActionContext.getServletContext()
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