Struts2中action獲取request、response、session的方式

第一種方式，非IoC(Spring中的控制反轉)方式：

1. package com.action;
2. import java.util.Map;
3. import javax.servlet.http.HttpServletRequest;
4. import javax.servlet.http.HttpServletResponse;
5. import org.apache.struts2.ServletActionContext;
6. import com.opensymphony.xwork2.ActionContext;
7. import com.opensymphony.xwork2.ActionSupport;
8. 
   
9. public class BaseAction extends ActionSupport {
10. private static final long serialVersionUID = 7620009925942346125L;
12. ActionContext context = ActionContext.getContext();
13. HttpServletRequest request = (HttpServletRequest) context.get(ServletActionContext.HTTP_REQUEST);
14. HttpServletResponse response = (HttpServletResponse) context.get(ServletActionContext.HTTP_RESPONSE);
15. Map session = context.getSession();
16. //SessionMap session = (SessionMap) context.get(ActionContext.SESSION);
18. }

咱們日常所說的session通常是HttpSession，但在struts2中被封裝成了Map類型。

第二種方式，IoC方式：

1. package com.action;
2. import java.util.Map;
3. import javax.servlet.http.HttpServletRequest;
4. import javax.servlet.http.HttpServletResponse;
5. import org.apache.struts2.dispatcher.SessionMap;
6. import org.apache.struts2.interceptor.ServletRequestAware;
7. import org.apache.struts2.interceptor.ServletResponseAware;
8. import org.apache.struts2.interceptor.SessionAware;
9. import com.opensymphony.xwork2.ActionContext;
10. import com.opensymphony.xwork2.ActionSupport;
11. 
    
12. public class BaseAction extends ActionSupport implements SessionAware, ServletRequestAware, ServletResponseAware {
13. private static final long serialVersionUID = 7620009925942346125L;
15. ActionContext context = ActionContext.getContext();
16. HttpServletRequest request;
17. HttpServletResponse response;
18. SessionMap session;
20. //獲取request,response,session方式一，非IoC方式，不用實現SessionAware, ServletRequestAware, ServletResponseAware
21. //ActionContext context = ActionContext.getContext();
22. //HttpServletRequest request = (HttpServletRequest) context.get(ServletActionContext.HTTP_REQUEST);
23. //HttpServletResponse response = (HttpServletResponse) context.get(ServletActionContext.HTTP_RESPONSE);
24. //Map session = context.getSession();
25. //SessionMap session = (SessionMap) context.get(ActionContext.SESSION);
27. //獲取request,response,session方式一，IoC方式，必須實現SessionAware, ServletRequestAware, ServletResponseAware
28. public void setSession(Map map) {
29. this.session = (SessionMap) map;
30. }
31. public void setServletRequest(HttpServletRequest request) {
32. this.request = request;
33. }
34. public void setServletResponse(HttpServletResponse response) {
35. this.response = response;
36. }
38. }

這樣咱們在寫action時直接繼承這個BaseAction，那些request、response、session之類就能夠正常地用了，good。等我下午有時間反編譯一下別人封裝好的BaseAction，看看是否是這樣搞的，哈哈。

ps：
平時咱們在action中要把值設進session而後在jsp頁面去的話，通常是這樣(struts2不行)：

1. public String findAllUsers() throws Exception {
3. List<User> userList = userService.findAllUsers();
5. HttpSession se = request.getSession();
6. se.setAttribute("userList", userList);
8. session.put("userList", userList);
9. //session.put("aaa", "bbb");
10. //session.put(key, value);
12. //request.setAttribute("userList", userList);
14. return SUCCESS;
15. }

在struts2中，設進session的話則應該變成這樣了，由於session是一個map類型：

1. public String findAllUsers() throws Exception {
3. List<User> userList = userService.findAllUsers();
4. session.put("userList", userList);
5. //request.setAttribute("userList", userList);
7. return SUCCESS;
8. }

聽說，若是直接到jsp頁面的話，通常推薦用request而不用session，多人單機同時操做的話保險一點，雖然一個瀏覽器同一時間只有一個session。

在jsp頁面取值的話：

1. <table class="table_report">
2. <tr>
3. <th>用戶ID</th>
4. <th>用戶名稱</th>
5. <th>用戶性別</th>
6. <th>用戶年齡</th>
7. <th>用戶地址</th>
8. <th>用戶電話</th>
9. <th>用戶郵箱</th>
10. </tr>
11. <!-- struts2最正規的取值方式 -->
12. <%-- <s:iterator id="user" value="%{#session.userList}">--%>
13. <s:iterator id="user" value="#session.userList">
14. <%-- <s:iterator id="user" value="#request.userList">--%>
15. <tr>
16. <td>${user.id}</td>
17. <td>${user.name}</td>
18. <td>${user.sex}</td>
19. <td>${user.age}</td>
20. <td>${user.address}</td>
21. <td>${user.phone}</td>
22. <td>${user.email}</td>
23. </tr>
24. </s:iterator>
25. </table>
26. <%-- 用完要清空 --%>
27. <%request.removeAttribute("userList");%>
28. <%--<%session.removeAttribute("userList");%>--%>