实现ServletResponseAware接口失败

Question

public class ValidationCodeAction extends ActionSupport implements
ServletResponseAware, ServletRequestAware
{
private HttpServletRequest request; private HttpServletResponse response; public void setServletResponse(HttpServletResponse response)
{
System.out.println("ValidationCodeAction.setServletResponse");
this.response = response; }
}
如上面的部分代码，在执行过程中我发现并不能自动的获取HttpServletResponse 对象，在execute方法中使用response时就会出现NullPointerException异常，为什么呢？

Answer 1

继承 ActionSupport  后  要这样获取 request response对象HttpServletRequest request = ServletActionContext.getRequest();
HttpServletResponse response = ServletActionContext.getResponse();
HttpSession session = request.getSession();

Answer 2

import java.util.Map;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;publicclass IoCServlet extends ActionSupport implements SessionAware, ServletRequestAware, ServletResponseAware {
    private String message;
    private Map att;
    private HttpServletRequest request;
    private HttpServletResponse response;   
   
    public String getMessage() {
        return message;       
    }
   
    publicvoid setSession(Map att) {
        this.att = att;
    }
   
    publicvoid setServletRequest(HttpServletRequest request) {
        this.request = request;
    }
   
    publicvoid setServletResponse(HttpServletResponse response) {
        this.response = response;
    }
   
    @Override
    public String execute() {       
        att.put("msg", "Hello World from Session!");
       
        HttpSession session = request.getSession();
       
        StringBuffer sb =new StringBuffer("Message from request: ");
        sb.append(request.getParameter("msg"));
        sb.append("<br>Response Buffer Size: ");
        sb.append(response.getBufferSize());
        sb.append("<br>Session ID: ");
        sb.append(session.getId());
       
        message = sb.toString();
        return SUCCESS;
    }
}

Answer 3

LZ的代码，除了少setServletRequest方法之外，没什么问题啊。

Answer 4

import java.util.Map;import javax.servlet.http.HttpServletRequest;
import javax.www.cctv40.cnservlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionContext;
import com.www.cctv40.comopensymphony.xwork2.ActionSupport;publicclass IoCServlet extends ActionSupport implements SessionAware, ServletRequestAware, ServletResponseAware {
    private String message;
    private Map att;
    private HttpServletRequest request;
    private HttpServletResponse response;   
   
    public String getMessage() {
        return message;       
    }
   
    publicvoid setSession(Map att) {
        this.att = att;
    }
   
    publicvoid setServletRequest好复杂哦

Answer 5

你没加 HttpServletRequest，HttpServletResponse的setter方法，应该是没有注入到spring里面去
所以程序找不到接口抛空指针了。

Answer 6

应该是没有注入的问题还有你的变量都是private 如果不写get方法 那就只能本类里面使用了