Struts2 拿到request session application的4种方法

1  第一种方法

public class LoginAction1 extends ActionSupport {
 
 private Map request;
 private Map session;
 private Map application;
 
 public LoginAction1() {
  System.out.println("hello");
  request = (Map)ActionContext.getContext().get("request");
  session = ActionContext.getContext().getSession();
  application = ActionContext.getContext().getApplication();
 }
 
 public String execute() {
  request.put("r1", "r1");
  session.put("s1", "s1");
  application.put("a1", "a1");
  return SUCCESS; 
 }
 
}
 
 
 
第二种方法  这种用的比较多
 package com.bjsxt.struts2.user.action;
import java.util.Map;
import org.apache.struts2.interceptor.ApplicationAware;
import org.apache.struts2.interceptor.RequestAware;
import org.apache.struts2.interceptor.SessionAware;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {
 
 private Map<String, Object> request;
 private Map<String, Object> session;
 private Map<String, Object> application;
 
 //DI dependency injection
 //IoC inverse of control
 public String execute() {
  request.put("r1", "r1");
  session.put("s1", "s1");
  application.put("a1", "a1");
  return SUCCESS; 
 }
 @Override
 public void setRequest(Map<String, Object> request) {
  this.request = request;
 }
 @Override
 public void setSession(Map<String, Object> session) {
  this.session = session;
 }
 @Override
 public void setApplication(Map<String, Object> application) {
  this.application = application;
 }
 
}
 
 
第三种方法
 package com.bjsxt.struts2.user.action;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class LoginAction3 extends ActionSupport {
 
 private HttpServletRequest request;
 private HttpSession session;
 private ServletContext application;
 
 public LoginAction3() {
  request = ServletActionContext.getRequest();
  session = request.getSession();
  application = session.getServletContext();
 }
 
 public String execute() {
  request.setAttribute("r1", "r1");
  session.setAttribute("s1", "s1");
  application.setAttribute("a1", "a1");
  return SUCCESS; 
 }
 
}