大二上每日总结

今日完成了Servlet+JSP+JDBC的综合案例，实现对学生姓名，成绩，编号的增删改查：

连接数据库的类：

public class DBHelper {
    private static String driver="com.mysql.jdbc.Driver";
    private static String url = "jdbc:mysql://localhost:3306/classname?useUnicode=true&characterEncoding=UTF-8"; //数据库名
    private static String username = "root";  //数据库用户名
    private static String password = "123456";  //数据库用户密码
    private static Connection conn=null;
    static
    {
        try
        {
            Class.forName(driver);
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }
    }
    public static Connection getConnection() throws SQLException
    {
        if(conn==null)
        {
            conn=  DriverManager.getConnection(url,username,password);
        }
        return  conn;
    }
    public static void main(String[] args)
    {
        try
        {
            Connection conn=DBHelper.getConnection();
            if(conn!=null)
            {
                System.out.println("数据库连接正常");
            }
            else
            {
                System.out.println("数据库连接异常");
            }
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }
    }
}

student数据类：

public class Studentdate {
    private Integer id;
    private String name;
    private Double score;
    private Date birthday;
    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 Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public Studentdate(Integer id,String name,Double score,Date birthday)
    {
        this.id=id;
        this.name=name;
        this.score=score;
        this.birthday=birthday;
    }
    public Studentdate(){}
}

servlet与filter：

@WebServlet("/student")
public class StudentServlet extends HttpServlet {
    private StudentRepository studentrs=new StudentRepository();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // TODO Auto-generated method stub
        String method=req.getParameter("method");
        if(method==null){
            method="findAll";
        }
        switch(method.charAt(0))
        {
        case 'f':
            List<Studentdate> list=null;
            try {
                list = studentrs.findAll();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            req.setAttribute("list", list);
            req.getRequestDispatcher("index.jsp").forward(req, resp);
            break;
        case 'd':
            String idstr=req.getParameter("id");        
            Integer id=Integer.parseInt(idstr);
            try {
                studentrs.delete(id);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            resp.sendRedirect("/biliwork2/student");
            break;
        case 'F':
            String idstr2=req.getParameter("id");        
            Integer id2=Integer.parseInt(idstr2);
            try {
                req.setAttribute("studate", studentrs.Find(id2));
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            req.getRequestDispatcher("update.jsp").forward(req, resp);
            break;
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // TODO Auto-generated method stub
        String method=req.getParameter("method");
        switch(method.charAt(0))
        {
        case 'a':
            String name=req.getParameter("name");
            String scorestr=req.getParameter("score");
            Double score=Double.parseDouble(scorestr);
            try {
                studentrs.add(name,score);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            resp.sendRedirect("/biliwork2/student");
        case 'u':
            String name1=req.getParameter("name");
            String idstr=req.getParameter("id");
            Integer id=Integer.parseInt(idstr);
            String scorestr1=req.getParameter("score");
            Double score1=Double.parseDouble(scorestr1);
            try {
                studentrs.update(id,name1,score1);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            resp.sendRedirect("/biliwork2/student");
            break;
        }
    }
    
}

@WebFilter("/student")
public class CharacterFilter implements Filter{

    public void destroy() {
        // TODO Auto-generated method stub
        
    }

    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain arg2) throws IOException, ServletException {
        // TODO Auto-generated method stub
        arg0.setCharacterEncoding("utf-8");
        arg2.doFilter(arg0, arg1);
    }

    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
        
    }

}

实现数据库的增删改查的类：

public class StudentRepository {
    public List<Studentdate> findAll() throws SQLException
    {
        List<Studentdate> list=new ArrayList<Studentdate>();
        Connection conn=DBHelper.getConnection();
        String sql="SELECT * FROM student";
        PreparedStatement ps=conn.prepareStatement(sql);
        ResultSet rs=ps.executeQuery();
        Studentdate studate=null;
        while(rs.next())
        {
            Integer id=rs.getInt(1);
            String name=rs.getString(2);
            Double score=rs.getDouble(3);
            Date birthday=rs.getDate(4);
            studate=new Studentdate(id,name,score,birthday);
            list.add(studate);
        }
        return list;
    }
    public void add(String name,Double score) throws SQLException
    {
        PreparedStatement ps=null;
        Connection conn=DBHelper.getConnection();
        conn.setAutoCommit(false);
        String sql="INSERT INTO student(name,score,birthday) values(?,?,?)";
        ps= conn.prepareStatement(sql);
        ps.setString(1,name);
        ps.setDouble(2,score);
        ps.setDate(3, new java.sql.Date(10));
        ps.executeUpdate();
        conn.commit();
    }
    public void delete(Integer id) throws SQLException
    {
        PreparedStatement ps=null;
        Connection conn=DBHelper.getConnection();
        conn.setAutoCommit(false);
        String sql="DELETE  FROM student where id=?";
        ps=conn.prepareStatement(sql);
        ps.setInt(1, id);
        ps.executeUpdate();
        conn.commit();
    }
    public Studentdate Find(Integer id) throws SQLException
    {
        Studentdate studate=null;
        PreparedStatement ps=null;
        Connection conn=DBHelper.getConnection();
        conn.setAutoCommit(false);
        ResultSet rs=null;
        String sql="SELECT * FROM student where id=?";
        ps=conn.prepareStatement(sql);
        ps.setInt(1,id);
        rs=ps.executeQuery();
        while(rs.next())
        {
            String name=rs.getString(2);
            Double score=rs.getDouble(3);
            Date birthday=rs.getDate(4);
            studate=new Studentdate(id,name,score,birthday);
        }
        return studate;
    }
    public void update(Integer id,String name,Double score) throws SQLException
    {
        PreparedStatement ps=null;
        Connection conn=DBHelper.getConnection();
        conn.setAutoCommit(false);
        String sql="UPDATE student set name=?,score=? where id=?";
        ps= conn.prepareStatement(sql);
        ps.setString(1,name);
        ps.setDouble(2,score);
        ps.setInt(3,id);
        ps.executeUpdate();
        conn.commit();
    }
}

以及三个jsp文件实现修改，增加，查询，删除界面显示：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'add.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
    <form action="/biliwork2/student" method="post">
      <table>
        <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="hidden" name="method" value="add">
        <td><input type="submit" value="提交"></td>
      </tr>
      </table>
    </form> <br>
  </body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%> 
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>
  <body>
    <h1>学生管理系统</h1>
    <table>
       <tr>
          <th>编号</th>
          <th>姓名</th>
          <th>成绩</th>
          <th>注册日期</th>
          <th>操作</th>
       </tr>
       <c:forEach items="${list}" var="studentdate" >
         <tr>
           <td>${studentdate.id}</td>
           <td>${studentdate.name}</td>
           <td>${studentdate.score}</td>
           <td>${studentdate.birthday}</td>
           <td>
             <a href="/biliwork2/student?method=delete&id=${studentdate.id }">删除</a>
             <a href="/biliwork2/student?method=Find&id=${studentdate.id }">修改</a>
         </tr>
       </c:forEach>
     </table> <br>
  </body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'add.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
    <form action="/biliwork2/student" method="post">
      <table>
        <tr>
          <td>编号</td>
          <td><input type="text" name="id" readonly value="${studate.id }"></td>
        </tr>
        <tr>
        <td>姓名</td>
        <td><input type="text" name="name" value="${studate.name }"></td>
      </tr>
      <tr>
        <td>成绩</td>
        <td><input type="text" name="score" value="${studate.score }"></td>
      </tr>
      <tr>
        <td><input type="hidden" name="method" value="update">
        <td><input type="submit" value="修改"></td>
      </tr>
      </table>
    </form> <br>
  </body>
</html>