大二上每日总结

今日完成了视频中javaBean+Servlet+jsp实现对用户增删改查的一个简单案例：

javaBean:

public class user {
    private Integer id;
    private String name;
    private Double score;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getScore() {
        return score;
    }
    public void setScore(Double score) {
        this.score = score;
    }
    public user(Integer id,String name,Double score)
    {
        this.id=id;
        this.name=name;
        this.score=score;
    }
}

Servlet:

    private Map<Integer,user> map;
    public UserServlet()
    {
        map=new HashMap<Integer,user>();
        map.put(1,new user(1,"张三",78.0));
        map.put(2,new user(2,"李四",68.3));
        map.put(3,new user(3,"王五",85.1));
    }
    @Override
    protected void doPost(HttpServletRequest req,HttpServletResponse resp)
    {
        try {
            req.setCharacterEncoding("utf-8");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        String idstr=req.getParameter("id");
        String namestr=req.getParameter("name");
        String scorestr=req.getParameter("score");
        Integer id=Integer.parseInt(idstr);
        Double score=Double.parseDouble(scorestr);
        user user=new user(id,namestr,score);
        map.put(user.getId(),user);
        try {
            resp.sendRedirect("/biliwork/user");
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
    }
    @Override
    protected void doGet(HttpServletRequest req,HttpServletResponse resp)
    {
        String flag=req.getParameter("flag");
        if(flag==null)
        {
            flag="findAll";
        }
        char Flag=flag.charAt(0);
        switch(Flag)
        {
         case 'd':
             String idstr=req.getParameter("id");
             Integer id=Integer.parseInt(idstr);
             map.remove(id);
             try {
                resp.sendRedirect("/biliwork/user");
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
             break;
         case 'f':
                req.setAttribute("map",map.values());
                try {
                    req.getRequestDispatcher("index.jsp").forward(req,resp);
                } catch (ServletException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            break;
         case 'u':
            idstr=req.getParameter("id");
            id=Integer.parseInt(idstr);
            req.setAttribute("user",map.get(id));
            try {
                req.getRequestDispatcher("update.jsp").forward(req,resp);
            } catch (ServletException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
             break;
        }

    }

jsp:

初始界面显示全部信息即查：

<body>
    <table>
      <tr>
        <th>编号</th>
        <th>姓名</th>
        <th>成绩</th>
        <th>操作</th>
      </tr>
      <c:forEach items="${map}" var="user">
        <tr>
          <td>${user.id}</td>
          <td>${user.name }</td>
          <td>${user.score }</td>
          <td><a href="/biliwork/user?flag=delete&id=${user.id}">删除</a></td>
          <td><a href="/biliwork/user?flag=upadate&id=${user.id}">修改</a></td>
        </tr>
      </c:forEach>
      <tr><td><a href="add.jsp">添加</a></td>
    </table><br>
  </body>

添加界面：

<body>
    <form action="/biliwork/user" method="post">
      <table>
      <tr>
        <td>编号</td>
        <td><input type="text" name="id"></td>
      </tr>
      <tr>
        <td>姓名</td>
        <td><input type="text" name="name"></td>
      </tr>
      <tr>
        <td>成绩</td>
        <td><input type="text" name="score"></td>
      <tr>
      <tr>
        <td><input type="submit" value="提交"></td>
      </tr>
      </table>
    </form> <br>
  </body>

更改界面：

  <body>
    <form action="/biliwork/user" method="post">
      <table>
      <tr>
        <td>编号</td>
        <td><input type="text" name="id" value="${user.id }" readonly></td>
      </tr>
      <tr>
        <td>姓名</td>
        <td><input type="text" name="name" value="${user.name}"></td>
      </tr>
      <tr>
        <td>成绩</td>
        <td><input type="text" name="score" value="${user.score }"></td>
      <tr>
      <tr>
        <td><input type="submit" value="修改"></td>
      </tr>
      </table>
    </form> <br>
  </body>

运行结果：

 

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原文地址：https://www.cnblogs.com/fengchuiguobanxia/p/13966410.html