struts2---以解耦合方式访问servletAPI

第一种：以ActionContext类访问ServletAPI
示例代码： [color=red]（注：request,sesssion,application用MaP集合存）

[/color]
public class UserAction extends ActionSupport {
	private String username;
	private String password;
	private Map<String ,Object> request;
	private Map<String ,Object> session;
	private Map<String ,Object> application;
	public String login(){
		//获取对象
		ActionContext ac=ActionContext.getContext();
		[color=red][size=large]request=(Map<String, Object>) ac.get("request");[/size][/color]//request对象必须用参数“request”获取
		session=ac.getSession();
		application=ac.getApplication();
		//保存数据
		request.put("loginCity", 北京");
		session.put("username", username);
		application.put("online", "在线人数：XXX");
		
		return SUCCESS;
	}
	//setter/getter方法省略
	
}

页面：用<s:property value="#request.loginCity"/> 抬头导入struts标签库
二。使用Ioc方式
使用哪个对象，则实现哪个接口，实现接口后实现接口的方法，把参数的值赋给成员变量
示例：action代码：

public class UserAction extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{
	private String username;
	private String password;
	private Map<String ,Object> request;
	private Map<String ,Object> session;
	private Map<String ,Object> application;
	public String login(){
		//保存数据
		request.put("loginCity", 北京");
		session.put("username", username);
		application.put("online", "在线人数：XXX");
		
		return SUCCESS;
	}
	
	public void setRequest(Map<String, Object> request) {
		this.request=request;
		
	}
	public void setSession(Map<String, Object> session) {
		this.session=session;
		
	}
	public void setApplication(Map<String, Object> application) {
		this.application=application;
		
	}
	//setter/getter方法
	
}

页面如第一方法所示