zoukankan      html  css  js  c++  java
  • javaweb简单的增删改查之“加”

    我相信对每一个初学者来说能有一个好的教程真的帮助非常大,虽然我也只是一个初学者,我相信我所学到的转化为自己的语言对大家会有帮助

    1.连接数据库

    public class Databass {
    public static String db_url = "jdbc:mysql://localhost:3306/blog?characterEncoding=utf8";
    public static String db_user = "root";
    public static String db_pass = "123";

    public static Connection getConn () {
    Connection conn = null;

    try {
    Class.forName("com.mysql.jdbc.Driver");//加载JDBC驱动
    System.out.println("JDBC加载成功");
    conn = DriverManager.getConnection(db_url, db_user, db_pass);
    System.out.println("数据库连接成功");
    } catch (Exception e) {
    e.printStackTrace();
    }

    return conn;
    }

    /**
    * 数据库用完之后是不是要关一下
    * @param state
    * @param conn
    */
    public static void close (Statement state, Connection conn) {
    if (state != null) {
    try {
    state.close();
    } catch (SQLException e) {
    e.printStackTrace();
    }
    }

    if (conn != null) {
    try {
    conn.close();
    } catch (SQLException e) {
    e.printStackTrace();
    }
    }
    }

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

    if (state != null) {
    try {
    state.close();
    } catch (SQLException e) {
    e.printStackTrace();
    }
    }

    if (conn != null) {
    try {
    conn.close();
    } catch (SQLException e) {
    e.printStackTrace();
    }
    }
    }
    public static void main(String[] args) {
    getConn ();

    }
    }

    2.创建JavaBean对数据库参数进行封装(也就是数据库中的表内容)

    public class Member {
    private String name;
    private String sex;
    public Member(String name, String sex) {
    super();
    this.name = name;
    this.sex = sex;
    }
    public String getName() {
    return name;
    }
    public void setName(String name) {
    this.name = name;
    }
    public String getSex() {
    return sex;
    }
    public void setSex(String sex) {
    this.sex = sex;
    }

    }

    3.方法,向数据库添加信息

    public class Method {
    Connection con=Databass.Databass.getConn();
    public boolean add(Member user) {
    boolean flash=false;
    PreparedStatement pre=null;
    String sql="insert into Blog value('"+user.getName()+"','"+user.getSex()+"')";
    try {
    pre=con.prepareStatement(sql);
    int i=pre.executeUpdate();
    if(i>0) {
    flash=true;
    }
    }catch(SQLException e) {
    e.printStackTrace();
    }finally {
    Databass.Databass.close(pre, con);
    }
    return flash;
    }

    }

    4.创建servlet(其实就是一个.java与.jsp或.html信息互相传递的一个过程)

    public class ServletAdd extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
    * @see HttpServlet#HttpServlet()
    */
    public ServletAdd() {
    super();
    // TODO Auto-generated constructor stub
    }

    /**
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    //设置请求字体
    request.setCharacterEncoding("utf-8");
    response.setContentType("text/html;charset=utf-8");
    //从HTML或jsp中获取数据
    String name=request.getParameter("name");
    String age=request.getParameter("age");
    //下面要做的就是吧获取的值添加到数据库中
    Method ww=new Method();
    ww.add(new Member(name,age));
    }

    }

    5.下面就是写一个非常简单的jsp文件

    <%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <form action="ServletAdd" method="post">
    姓名:
    <input type="text" name="name"><br>
    年龄:
    <input type="text" name="age"><br>
    <input type="submit" value="添加">
    </form>

    </body>
    </html>

    结果如下:

     虽然非常简单,但是以后难度会增加的,这是我第一次认真的写博客!

  • 相关阅读:
    jackson学习之一:基本信息 jackson学习之二:jackson-core
    FastAPI项目实战:SayHello(FastAPI + vue.js + axios + element ui 翻自Flask版
    MarkDown优雅发表
    docker使用笔记
    JVM的重要性 从上层应用程序到底层操作系统,到底有哪些东西?
    Python正则表达式re模块和os模块实现文件搜索模式匹配
    区块链学习6:图灵完备和图灵不完备
    moviepy音视频开发:使用credits1给视频加片头片尾字幕
    moviepy音视频开发:使用volumex调节音量大小及其花式用法
    moviepy音视频开发:audio_normalize调整剪辑音量大小到正常
  • 原文地址:https://www.cnblogs.com/lianggegege123/p/12052227.html
Copyright © 2011-2022 走看看