500出错了?

来源:3-3 综合训练-实现新增员工功能

Ctrlzhao

2019-11-20 23:12:49

package com.imooc.employee;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class CreateServlet
 */
@WebServlet("/create")
public class CreateServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CreateServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		String empno=request.getParameter("empno");
		String ename=request.getParameter("enaem");
		String department=request.getParameter("department");
		String job=request.getParameter("job");
		String salary=request.getParameter("salary");
		System.out.println(empno);
		
		
		Employee emp=new Employee(Integer.parseInt(empno),ename,department,job,Float.parseFloat(salary));
		ServletContext context=request.getServletContext();
		List employees=(List)context.getAttribute("employees");
		employees.add(emp);
		context.setAttribute("employees", employees);
		request.getRequestDispatcher("/employee.jsp").forward(request, response);
	}

}

http://img.mukewang.com/climg/5dd557ee09c87bb418720874.jpg

写回答

1回答

好帮手慕小班

2019-11-21

同学你好,根据报错信息,代码第44行报出NullPointerException异常-->空指针异常,说明employees是null。

http://img.mukewang.com/climg/5dd6318d0926520309990466.jpg

这里测试贴出的CreateServlet在老师的代码中,并没有报出控制针异常的错误,所以同学可以检查自己的ListServlet中,employees单词是否书写正确,导致CreateServlet没有获取到employees的对应内容,例如:

http://img.mukewang.com/climg/5dd63234098e483208820300.jpg

如果我的回答解决了你的疑惑,请采纳。祝:学习愉快~

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