java操做數據庫，以頁面顯示學生信息爲例

時間 2019-12-09
原文原文鏈接
該部份內容實現的功能主要是：從數據庫中查詢數據並展現到頁面，在頁面中新增數據信息，在頁面中修改數據信息，在頁面中刪除數據信息。



=================stuList.jsp================
//本頁爲數據顯示頁面
<%@ page import="java.util.List" %>
<%@ page import="com.ibeifeng.student.Student" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>stuList</title>
</head>
<body>
<a href="addStu.jsp">新增學員</a>
<table width="100%" border="1px solid black">
    <tr>
        <td>學號</td>
        <td>姓名</td>
        <td>密碼</td>
        <td>性別</td>
        <td>郵箱</td>
        <td>操做</td>
    </tr>
    <%
        List<Student> list = (List<Student>)request.getAttribute("list");
        for(Student stu : list){
    %>
            <tr>
                <td><%=stu.getId()%></td>
                <td><%=stu.getName()%></td>
                <td><%=stu.getPwd()%></td>
                <td><%=stu.getSex()%></td>
                <td><%=stu.getEmail()%></td>
                <td><a href="updateStu.jsp?sid=<%=stu.getId()%>">修改</a> | <a href="doDel.jsp?sid=<%=stu.getId()%>">刪除</a></td>
            </tr>
    <%    }
    %>
</table>
</body>
</html>



===============doList02.jsp==================
//本頁是數據顯示頁面stuList的後臺數據處理部分
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="com.ibeifeng.student.Student" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.List" %>
<%@ page import="com.ibeifeng.student.ConfigUtil" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    Class.forName(new ConfigUtil().getValue("driver"));
    Connection conn = DriverManager.getConnection(
            new ConfigUtil().getValue("url"),
            new ConfigUtil().getValue("username"),
            new ConfigUtil().getValue("password"));

    String sql = "select * from student";
    PreparedStatement ps = conn.prepareStatement(sql);
    ResultSet rs = ps.executeQuery();
    List<Student> list = new ArrayList<Student>();
    while(rs.next()){
        Student stu = new Student();
        stu.setId(rs.getInt(1));
        stu.setName(rs.getString(3));
        stu.setPwd(rs.getString(2));
        stu.setSex(rs.getInt(4));
        stu.setEmail(rs.getString(5));
        list.add(stu);
    }

    if(rs != null){
        rs.close();
    }
    if(ps != null){
        ps.close();
    }
    if(conn != null){
        conn.close();
    }

    request.setAttribute("list",list);
    request.getRequestDispatcher("stuList.jsp").forward(request,response);
%>



====================addStu.jsp==============
//本頁爲新增數據的頁面展現部分
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>新增學員信息</title>
</head>
<body>
<form action="doSave.jsp" method="post">
    <table align="center" border="1px solid black">
        <tr>
            <td>學號</td>
            <td><input type="text" name="stuId" > </td>
        </tr>
        <tr>
            <td>姓名</td>
            <td><input type="text" name="stuName" ></td>
        </tr>
        <tr>
            <td>密碼</td>
            <td><input type="password" name="pwd" ></td>
        </tr>
        <tr>
            <td>性別</td>
            <td>
                <input type="radio" name="gender" value="0">女
                <input type="radio" name="gender" value="1">男
            </td>
        </tr>
        <tr>
            <td>郵箱</td>
            <td><input type="text" name="email" ></td>
        </tr>
        <tr>
            <td colspan="2">
                <input type="submit" name="submit" value="保存">
                <input type="button" name="return" value="取消">
            </td>
        </tr>
    </table>
</form>
</body>
</html>



===================doSave.jsp==============
//本頁爲數據新增頁面，保存按鈕的數據處理部分
<%@ page import="com.ibeifeng.student.ConfigUtil" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    request.setCharacterEncoding("utf-8");
    response.setCharacterEncoding("utf-8");

    Class.forName(new ConfigUtil().getValue("driver"));
    Connection conn = DriverManager.getConnection(
            new ConfigUtil().getValue("url"),new ConfigUtil().getValue("username"),new ConfigUtil().getValue("password"));

    String sql = "insert into student(stu_id,stu_name,pwd,sex,email) values(?,?,?,?,?)";
    PreparedStatement ps = conn.prepareStatement(sql);

    String rid = request.getParameter("stuId");
    int id =  Integer.parseInt(rid);
    ps.setInt(1,id);
    ps.setString(2,request.getParameter("stuName"));
    ps.setString(3,request.getParameter("pwd"));
    ps.setInt(4,1);
    ps.setString(5,request.getParameter("email"));

    int isSuccess = ps.executeUpdate();
    System.out.print(isSuccess);
    if(isSuccess <= 0){
        System.out.print("新增有誤，請重試");
        request.getRequestDispatcher("/stuInfo/addStu.jsp").forward(request,response);
    }else{
        request.getRequestDispatcher("/stuInfo/doList02.jsp").forward(request,response);
    }

    if(ps != null){
        ps.close();
    }
    if(conn != null){
        conn.close();
    }
%>




================updateStu.jsp===============
//本頁爲數據修改頁面展現部分
<%@ page import="com.ibeifeng.student.StudentDao" %>
<%@ page import="com.ibeifeng.student.Student" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%
    request.setCharacterEncoding("utf-8");
    response.setCharacterEncoding("utf-8");
    //獲取前端頁面傳遞的參數
    String sid = request.getParameter("sid");   //該參數由stuList頁面的<a href="updateStu.jsp?sid=stu.getStudentId()">傳遞過來
   //建立StudentDao對象
    StudentDao stuDao = new StudentDao();
    Student stu = stuDao.getStuByStuId(sid);

    if(stu != null){
        request.setAttribute("stu",stu);
    }

%>

<html>
<head>
    <title>新增學員信息</title>
</head>
<body>
<form action="doUpdate.jsp" method="post">
    <table align="center" border="1px solid black">
        <tr>
            <td>學號</td>
            <td><input type="text" name="stuId" readonly="readonly" value="<%=stu.getId()%>"> </td>
        </tr>
        <tr>
            <td>姓名</td>
            <td><input type="text" name="stuName" value="<%=stu.getName()%>"></td>
        </tr>
        <tr>
            <td>密碼</td>
            <td><input type="password" name="pwd" value="<%=stu.getPwd()%>"></td>
        </tr>
        <tr>
            <td>性別</td>
            <td>
                <input type="radio" name="gender" value="0" <%if(stu.getSex() == 0){%>checked="checked"<%}%>>女
                <input type="radio" name="gender" value="1" <%if(stu.getSex() == 1){%>checked="checked"<%}%>>男
            </td>
        </tr>
        <tr>
            <td>郵箱</td>
            <td><input type="text" name="email" value="<%=stu.getEmail()%>"></td>
        </tr>
        <tr>
            <td colspan="2">
                <input type="submit" name="submit" value="保存">
                <input type="button" name="return" value="取消">
            </td>
        </tr>
    </table>
</form>
</body>
</html>



=================doUpdate.jsp==============
//本頁爲數據修改部分，後臺數據處理操做的內容
<%@ page import="com.ibeifeng.student.ConfigUtil" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="com.ibeifeng.student.StudentDao" %>
<%@ page import="com.ibeifeng.student.Student" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    request.setCharacterEncoding("utf-8");
    response.setCharacterEncoding("utf-8");

    Class.forName(new ConfigUtil().getValue("driver"));
    Connection conn = DriverManager.getConnection(
            new ConfigUtil().getValue("url"),new ConfigUtil().getValue("username"),new ConfigUtil().getValue("password"));

    String stuid = request.getParameter("stuId");
    int sid = Integer.parseInt(stuid);
    String name = request.getParameter("stuName");
    String pwd = request.getParameter("pwd");
    String gender = request.getParameter("gender");
    int gen = Integer.parseInt(gender);
    String email = request.getParameter("email");

    StudentDao stuDao = new StudentDao();
    Student stu = new Student();
    stu.setId(sid);
    stu.setName(name);
    stu.setPwd(pwd);
    stu.setSex(gen);
    stu.setEmail(email);

    int resule = stuDao.updateStu(stu);
    if(resule > 0){
        request.getRequestDispatcher("doList02.jsp").forward(request,response);
    }else{
        request.getRequestDispatcher("updateStu.jsp?sno="+stuid).forward(request,response);
    }
%>



===============doDel.jsp===================
//本頁爲數據刪除部分後臺處理內容
<%@ page import="com.ibeifeng.student.StudentDao" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    request.setCharacterEncoding("utf-8");
    response.setCharacterEncoding("utf-8");

    String sid = request.getParameter("sid");
    StudentDao stuDao = new StudentDao();
    stuDao.delStu(sid);
    request.getRequestDispatcher("doList02.jsp").forward(request,response);
%>





===============BaseDao.java=================
//本頁爲封裝的方法，主要是涉及到數據庫鏈接的初始化、查詢、更新、資源釋放
package com.ibeifeng.student;

import java.sql.*;

/*
* JDBC操做DAO通用類方法封裝
* */
public class BaseDao {
    static Connection conn = null;
    static PreparedStatement ps = null;
    static ResultSet rs = null;
    //靜態語句塊
    static{
        try {
            Class.forName(ConfigUtil.getValue("driver"));

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    public static Connection getConn(){
        try {
            conn = DriverManager.getConnection(ConfigUtil.getValue("url"),
                    ConfigUtil.getValue("username"),
                    ConfigUtil.getValue("password"));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    /*
    * 查詢
    * */
    public ResultSet search(String sql){
        try {
            rs = ps.executeQuery();
            return rs;
        } catch (SQLException e) {
            throw new RuntimeException();
        }
    }

    /*
    * 更新數據
    * */
    public int modify(String sql){
        try {
            return ps.executeUpdate(sql);
        } catch (SQLException e) {
            throw new RuntimeException();
        }
    }

    public static void close(ResultSet rs, PreparedStatement ps, Connection conn){
        try {
            if(rs != null) {
                rs.close();
            }
            if(ps != null) {
                ps.close();
            }
            if(conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}





=================ConfigUtil.java==============
//本頁封裝了從配置文件讀取數據的方法
package com.ibeifeng.student;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class ConfigUtil {
    //經過key獲取jdbc配置的value
    public static String getValue(String key){
        Properties pro = new Properties();
        //獲取流信息
        InputStream is = ConfigUtil.class.getResourceAsStream("/jdbc.properties");
        try {
            //加載流文件
            pro.load(is);
            //獲取屬性值
            return pro.getProperty(key);
        } catch (IOException e) {
            throw new RuntimeException();
        }
    }
}





================StudentDao.java==============
//本頁封裝了對於數據庫，數據處理的一些方法
package com.ibeifeng.student;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class StudentDao {
    /*
    * Student Dao用於處理Student類
    * */
    Connection conn = null;
    PreparedStatement ps = null;
    public int updateStu(Student stu){
        /*
        * 更新學員信息
        * */
        String sql = "update student set stu_name=?,pwd=?,sex=?,email=? where stu_id=?";
        try {
            ps = BaseDao.getConn().prepareStatement(sql);
            ps.setString(1,stu.getName());
            ps.setString(2,stu.getPwd());
            ps.setInt(3,stu.getSex());
            ps.setString(4,stu.getEmail());
            ps.setInt(5,stu.getId());

            return ps.executeUpdate();
        } catch (SQLException e) {
            throw new RuntimeException();
        }finally {
            BaseDao.close(null,ps,conn);
        }
    }

    public Student getStuByStuId(String stu_id){
        String sql = "select * from student where stu_id=?";
        Student stu = null;
        try {
            conn = BaseDao.getConn();
            ps = conn.prepareStatement(sql);
            int sid = Integer.parseInt(stu_id);
            ps.setInt(1,sid);
            ResultSet rs = ps.executeQuery();

            if(rs.next()){
                stu = new Student();
                stu.setId(rs.getInt("stu_id"));
                stu.setName(rs.getString("stu_name"));
                stu.setPwd(rs.getString("pwd"));
                stu.setSex(rs.getInt("sex"));
                stu.setEmail(rs.getString("email"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            BaseDao.close(null,ps,conn);
        }
        return stu;
    }

    /*
    * 根據學號刪除學生信息
    * */
    public int delStu(String sid){
        String sql = "delete from student where stu_id = ?";
        conn = BaseDao.getConn();
        try {
            ps = conn.prepareStatement(sql);
            int id = Integer.parseInt(sid);
            ps.setInt(1,id);
            return ps.executeUpdate();
        } catch (SQLException e) {
            throw new RuntimeException();
        }
    }
}






===================Student.java==============
//封裝類對象
package com.ibeifeng.student;

public class Student {
    private int id;
    private String name;
    private String pwd;
    private int sex;
    private String email;

    public Student(){}

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

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

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    public void setSex(int sex) {
        this.sex = sex;
    }

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

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getPwd() {
        return pwd;
    }

    public int getSex() {
        return sex;
    }

    public String getEmail() {
        return email;
    }
}




=============jdbc.properties=============
//配置文件信息
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=123456