Struts2访问ServletAPI（向JSP内置对象request，session，Application传值）

JSP:         request                                 session                                   application

Servlet：HttpServletRequest            HttpSession                            ServletContext

Struts2可通过ActionContext类，ServletActionContext类和IoC（接口）方式访问这三个对象。

ActionContext类：

package com.hp.easycar.action;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginServletAPI1 extends ActionSupport {
private String username;
private String password;
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;
}

@Override
public void validate() {
if (username==null||username.trim().equals("")) {
addFieldError("username", "输入的用户名不能为空！！");
}
if (password==null||password.trim().equals("")) {
addFieldError("password", "输入的用户名不能为空！！");
}
}

@Override
public String execute() throws Exception {
if (username.equals("hp")&&password.equals("hp123")) {
//获取ActionContext对象
<strong>ActionContext context=ActionContext.getContext();</strong>
//在请求request中保存欢迎信息
<strong>context.put("welcome", "欢迎您登录HP EasyCar系统！");</strong>
//在Session中保存用户名
<strong>context.getSession().put("username", "HP");</strong>
//统计用户量，在Apllacation中保存
<strong>Integer count=(Integer) context.getApplication().get("counter");</strong>
if (count==null) {
count=1;
} else {
count++;
}
<strong>context.getApplication().put("counter", count);</strong>
return SUCCESS;
} else {
return ERROR;
}
}
}
ServletActionContext类：

package com.hp.easycar.action;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginServletAPI2 extends ActionSupport {
private String username;
private String password;
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;
}

@Override
public void validate() {
if (username==null||username.trim().equals("")) {
addFieldError("username", "输入的用户名不能为空！！");
}
if (password==null||password.trim().equals("")) {
addFieldError("password", "输入的用户名不能为空！！");
}
}

@Override
public String execute() throws Exception {
if (username.equals("hp")&&password.equals("hp123")) {
//在请求request中保存欢迎信息
<strong>ServletActionContext.getRequest().setAttribute("welcome", "欢迎您登录HP EasyCar系统！");</strong>
//在Session中保存用户名
<strong>ServletActionContext.getRequest().getSession().setAttribute("username", "HP");</strong>
//统计用户量，在Apllacation中保存
<strong>Integer count=(Integer)ServletActionContext.getServletContext().getAttribute("counter");</strong>
if (count==null) {
count=1;
} else {
count++;
}
<strong>ServletActionContext.getServletContext().setAttribute("counter", count);</strong>
return SUCCESS;
} else {
return ERROR;
}
}
}
IoC

package com.hp.easycar.action;

import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.SessionAware;
import org.apache.struts2.util.ServletContextAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginServletAPI3 extends ActionSupport implements
<strong>ServletRequestAware, SessionAware, ServletContextAware</strong> {
<strong> private static final long serialVersionUID=1004770319661315412L;
private HttpServletRequest request;
private Map<String,Object> session;
private ServletContext context;</strong>
////////////

private String username;
private String password;
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;
}

@Override
public void validate() {
if (username==null||username.trim().equals("")) {
addFieldError("username", "输入的用户名不能为空！！");
}
if (password==null||password.trim().equals("")) {
addFieldError("password", "输入的用户名不能为空！！");
}
}

@Override
public String execute() throws Exception {
if (username.equals("hp")&&password.equals("hp123")) {
//在请求request中保存欢迎信息
<strong>request.setAttribute("welcome", "欢迎您登录HP EasyCar系统！");</strong>
//在Session中保存用户名
<strong>session.put("username", "HP");</strong>
//统计用户量，在Apllacation中保存
<strong>Integer count=(Integer)context.getAttribute("counter");</strong>
if (count==null) {
count=1;
} else {
count++;
}
<strong> context.setAttribute("counter", count);</strong>
return SUCCESS;
} else {
return ERROR;
}
}

/////////////

<strong>@Override
public void setServletContext(ServletContext arg0) {
// TODO Auto-generated method stub

}

@Override
public void setSession(Map<String, Object> arg0) {
// TODO Auto-generated method stub

}

@Override
public void setServletRequest(HttpServletRequest arg0) {
// TODO Auto-generated method stub

}</strong>

}


使用HttpServletRequest:实现ServletRequestAware接口，并重写public void setServletContext(ServletContext arg0)方法
使用HttpServletSession:实现 SessionAware,接口，并重写public void setSession(Map<String, Object> arg0)方法

使用ServletContext实现ServletContextAware接口，并重写public void setServletRequest(HttpServletRequest arg0) 方法