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标题: [成都校区]这些天，走在web服务器中所遇到的bug [打印本页]

作者: 訫愿遂 时间: 2018-11-22 09:05
标题: [成都校区]这些天，走在web服务器中所遇到的bug
   从开始接触web到现在学习这一块已经接近尾声经历了大半个月的学习，回想一下，有MySQL . JDBC . HTML . JAVASCRIPT .CSS . BOOSTRAP . XML . TOMCAT .SERVLET . COOKIE . SEESION,然后现在综合以上的学习内容，我们就在实体操作，进行案例的练习。在这段日子中，我们常常会遇到各种bug,比如什么exception,404,500,特别是在jsp中，由于HTML本身语法不严谨，导致有代码编写写错也不会报错，就我个人而言，我就把form标签中的form写成from,最后一个个找错，很恼火！
      昨天，我敲了一下案例的代码，需求是通过查看用户信息这个超链接，展示一个用户表格的数据。而我昨天编写就出了这么个bug:ClassNotFoundException,排查了两个小时，最后发现在细节上出了问题，木有在WEB-INF目录下创一个lib文件夹，而是把资源jar包直接导在WEB-INF 底下，实在太同意了，所以以后写项目一定要细心，按标准格式规范写。最后展示一下我的代码：
package cn.itcast.domain;

public class User {
private int id;
private String name;
private String gender;
private int age;
private String address;
private String qq;
private String email;

public int getId() {
      return id;
}

public void setId(int id) {
      this.id = id;
}

public String getName() {
      return name;
}

public void setName(String name) {
      this.name = name;
}

public String getGender() {
      return gender;
}

public void setGender(String gender) {
      this.gender = gender;
}

public int getAge() {
      return age;
}

public void setAge(int age) {
      this.age = age;
}

public String getAddress() {
      return address;
}

public void setAddress(String address) {
      this.address = address;
}

public String getQq() {
      return qq;
}

public void setQq(String qq) {
      this.qq = qq;
}

public String getEmail() {
      return email;
}

public void setEmail(String email) {
      this.email = email;
}

@Override
public String toString() {
      return "User{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", gender='" + gender + '\'' +
            ", age=" + age +
            ", address='" + address + '\'' +
            ", qq='" + qq + '\'' +
            ", email='" + email + '\'' +
            '}';
}
}

package cn.itcast.web.servlet;

import cn.itcast.domain.User;
import cn.itcast.service.ServiceUser;
import cn.itcast.service.impl.ServiceUserImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/servletUserList")
public class ServletUserList extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      //用于解决请求乱码问题
      request.setCharacterEncoding("utf-8");
      ServiceUser service = new ServiceUserImpl();
      List<User> users = service.findAll();
      request.setAttribute("users",users);
      request.getRequestDispatcher("/list.jsp").forward(request,response);
}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      this.doPost(request, response);
}
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>

<html lang="zh-CN">
<head>

<meta charset="utf-8">

<meta http-equiv="X-UA-Compatible" content="IE=edge">

<meta name="viewport" content="width=device-width, initial-scale=1">

<title>用户信息管理系统</title>


<link href="css/bootstrap.min.css" rel="stylesheet">

<script src="js/jquery-2.1.0.min.js"></script>

<script src="js/bootstrap.min.js"></script>
<style type="text/css">
      td, th {
         text-align: center;
      }
</style>
</head>
<body>
<div class="container">
<h3 style="text-align: center">用户信息列表</h3>
<table border="1" class="table table-bordered table-hover">
      <tr class="success">
         <th>编号</th>
         <th>姓名</th>
         <th>性别</th>
         <th>年龄</th>
         <th>籍贯</th>
         <th>QQ</th>
         <th>邮箱</th>
         <th>操作</th>
      </tr>
      <c:forEach items="${users}" var="user" varStatus="s">
         <tr>
            <td>${s.count}</td>
            <td>${user.name}</td>
            <td>${user.gender}</td>
            <td>${user.age}</td>
            <td>${user.address}</td>
            <td>${user.qq}</td>
            <td>${user.email}</td>
            <td><a class="btn btn-default btn-sm" href="update.html">修改</a> <a class="btn btn-default btn-sm" href="">删除</a></td>
         </tr>
      </c:forEach>

      <tr>
         <td colspan="8" align="center"><a class="btn btn-primary" href="add.html">添加联系人</a></td>
      </tr>
</table>
</div>
</body>
</html>

public interface ServiceUser {
List<User> findAll();
}

public class ServiceUserImpl implements ServiceUser {
@Override
public List<User> findAll() {
      List<User> users = new UserDaoImpl().findAll();
      return users;
}
}

public interface UserDao {
List<User> findAll();
}

public class UserDaoImpl implements UserDao {
private JdbcTemplate template=new JdbcTemplate(JDBCUtils.getDataSource());
@Override
public List<User> findAll() {
      String sql="select * from user";
      List<User> list = template.query(sql, new BeanPropertyRowMapper<User>(User.class));
      return list;
}
}

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