麻烦老师帮我看下，为什么是空指针呢？
package com.imooc.sm.global;
import com.imooc.sm.entity.Log;
import com.imooc.sm.entity.Staff;
import com.imooc.sm.service.LogService;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
@Component
@Aspect
public class LogAdvice {
@Autowired
private LogService logService;
@After("execution(* com.imooc.sm.controller.*.*(..)) && !execution(* com.imooc.sm.controller.SelfController.*(..))")
public void operationLog(JoinPoint joinPoint) {
Log log = new Log();
log.setMoudle(joinPoint.getTarget().getClass().getSimpleName());
log.setOperation(joinPoint.getSignature().getName());
HttpServletRequest request = (HttpServletRequest) joinPoint.getArgs()[0];
HttpSession session = request.getSession();
Object obj = session.getAttribute("USER");
Staff staff = (Staff) obj;
log.setOperator(staff.getAccount());
log.setResult("成功");
logService.addOperationLog(log);
}
@AfterThrowing(throwing = "e", pointcut = "execution(* com.imooc.sm.controller.*.*(..))")
public void systemLog(JoinPoint joinPoint, Throwable e) {
Log log = new Log();
log.setMoudle(joinPoint.getTarget().getClass().getSimpleName());
log.setOperation(joinPoint.getSignature().getName());
HttpServletRequest request = (HttpServletRequest) joinPoint.getArgs()[0];
HttpSession session = request.getSession();
Object obj = session.getAttribute("USER");
Staff staff = (Staff) obj;
log.setOperator(staff.getAccount());
log.setResult(e.getClass().getSimpleName());
logService.addSystemLog(log);
}
@After("execution(* com.imooc.sm.controller.SelfController.login(..))")
public void loginLog(JoinPoint joinPoint) {
Log log = new Log();
log.setMoudle(joinPoint.getTarget().getClass().getSimpleName());
log.setOperation(joinPoint.getSignature().getName());
HttpServletRequest request = (HttpServletRequest) joinPoint.getArgs()[0];
HttpSession session = request.getSession();
Object obj = session.getAttribute("USER");
if (obj == null) {
log.setOperation(request.getParameter("account"));
log.setResult("失败");
} else {
Staff staff = (Staff) obj;
log.setOperator(staff.getAccount());
log.setResult("成功");
}
logService.addLoginLog(log);
}
@Before("execution(* com.imooc.sm.controller.SelfController.logout(..))")
public void logoutLog(JoinPoint joinPoint) {
Log log = new Log();
log.setMoudle(joinPoint.getTarget().getClass().getSimpleName());
log.setOperation(joinPoint.getSignature().getName());
HttpServletRequest request = (HttpServletRequest) joinPoint.getArgs()[0];
HttpSession session = request.getSession();
Object obj = session.getAttribute("USER");
if (obj == null) {
log.setOperation(request.getParameter("account"));
log.setResult("失败");
} else {
Staff staff = (Staff) obj;
log.setOperator(staff.getAccount());
log.setResult("成功");
}
logService.addLoginLog(log);
}
}
进不去个人中心哦
正在回答
空指针异常，既获用null去调方法，或属性。那么，同学看到的是哪行报空指针异常呢？
从同学的截图看，
obj为null。那么，我们是在哪里向域中存的呢？
是在下图中的红框位置。
建议同学看一下，是否在下图的红框位置向域中设置了user 呢？如果设置了，建议在前边打印一句输出语句，看看是否执行到这儿了。
如果我的回答解决了你的疑惑，请采纳！祝学习愉快！
package com.imooc.sm.controller;
import com.imooc.sm.entity.Staff;
import com.imooc.sm.service.SelfService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
@Controller("selfController")
public class SelfController {
@Autowired
private SelfService selfService;
public void toLogin(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("login.jsp").forward(request, response);
}
public void main(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("index.jsp").forward(request, response);
}
public void login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String account = request.getParameter("account");
String password = request.getParameter("password");
Staff staff = selfService.login(account, password);
if (staff == null) {
response.sendRedirect("toLogin.do");
} else {
HttpSession session = request.getSession();
session.setAttribute("USER", staff);
response.sendRedirect("main.do");
System.out.println(staff);
}
}
public void logout(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("USER", null);
response.sendRedirect("toLogin.do");
}
public void info(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("../info.jsp").forward(request, response);
}
public void toChangePassword(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("../change_password.jsp").forward(request, response);
}
public void changePassword(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String password = request.getParameter("password");
String password1 = request.getParameter("password1");
HttpSession session = request.getSession();
Staff staff = (Staff) session.getAttribute("USER");
if (!staff.getPassword().equals(password)) {
response.sendRedirect("toChangePassword.do");
} else {
selfService.changePassword(staff.getId(), password1);
response.sendRedirect("../logout.do");
response.getWriter().print("<script type=\"text/javascript\">parent.location.href=\"../logout.do\"</script>");
;
}
}
}相似问题
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