本实验实现简单的增加功能，实现连接数据库。
首先需要在eclipse里建立一个Dynamic Web Project项目，截图如下
（java web 必须创建在这样的文件夹内）
点击上述项目后，会出现如下界面，首先输入项目的名称，本次项目名称为deng_lu,输入名称后点击Finish完成。
建立完项目后看一下项目的总览，一共有6个东西需要添加，添加完这六个东西后，再在navicat里加一个表就可以完成了：
1.首先Bean的代码如下
package bean;
public class Bean {
private String zhanghao;
private int password;
private String shenfen;
public String getZhanghao() {
return zhanghao;
}
public void setZhanghao(String zhanghao) {
this.zhanghao = zhanghao;
}
public int getPassword() {
return password;
}
public void setPassword(int password) {
this.password = password;
}
public String getShenfen() {
return shenfen;
}
public void setShenfen(String shenfen) {
this.shenfen = shenfen;
}
public Bean(String zhanghao,int password,String shenfen) {
this.zhanghao = zhanghao;
this.password = password;
this.shenfen = shenfen;
}
public String toString() {
return "Bean [zhanghao=" + zhanghao + ", password=" + password + ", shenfen=" + shenfen + "]";
}
}
2.Dao类代码如下
package dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import bean.Bean;
import db.DBUtil;
public class Dao {//dao层
private DBUtil dbutil=new DBUtil();
public Dao() {
// TODO Auto-generated constructor stub
}
public boolean insert(Bean bean) {//插入数据的方法
boolean f=false;
String sql="insert into denglu(zhanghao,password,shenfen) values('"+bean.getZhanghao()+"','"+bean.getPassword()+"','"+bean.getShenfen()+"')";
Connection conn=DBUtil.getConnection();//数据库连接，加载驱动
Statement state=null;//？定义state对象
try
{
state=conn.createStatement();//实例化Statement对象,方便对sql语句进行操作
System.out.println(conn);//？
state.executeUpdate(sql);//？
f=true;
//执行数据库更新操作用于执行INSERT、UPDATE或DELETE语句以及SQLDDL（数据定义语言）语句，
//例如CREATETABLE和DROPTABLE,（创建表和删除表）
}catch(Exception e)//当try语句中s出现异常时，会执行catch中的语句
{
e.printStackTrace();//捕获异常的语句
}
finally //finally作为异常处理的一部分，它只能用在try/catch语句中，并且附带一个语句块，表示这段语句最终一定会被执行（不管有没有抛出异常），经常被用在需要释放资源的情况下。
{
DBUtil.close(conn);
}
return f;
}
}
3.DBUtil类代码如下：
package db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DBUtil {
private static String url = "jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC";
private static String user = "root";
private static String password = "3wcnasdqaz";
private static String jdbcName="com.mysql.cj.jdbc.Driver";
private Connection con=null;
public static Connection getConnection() {
Connection con=null;
try {
Class.forName(jdbcName);
con=DriverManager.getConnection(url, user, password);
//System.out.println("数据库连接成功");
} catch (Exception e) {
// TODO Auto-generated catch block
//System.out.println("数据库连接失败");
e.printStackTrace();
}
try {
con = DriverManager.getConnection(url,user,password);
System.out.println("连接成功");
} catch (SQLException e) {
// TODO: handle exception
e.printStackTrace();
}
return con;
}
public static void main(String[] args)throws SQLException {
Connection conn = getConnection();
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql ="select * from denglu";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
System.out.println(getConnection());
while(rs.next()){
System.out.println("成功");
}
}
// return con;
public static void close(Connection con) {
if(con!=null)
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
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();
}
}
}
}
4.servlet代码如下：（这个要建立servlet文件）
package servlet;
import java.io.IOException;
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 bean.Bean;
import dao.Dao;
/**
* Servlet implementation class servlet
*/
@WebServlet("/servlet")
public class servlet extends HttpServlet {
Dao dao=new Dao();
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public servlet() {
super();
// TODO Auto-generated constructor stub
}
private void insert(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
String zhanghao= request.getParameter("zhanghao");
int password= Integer.parseInt(request.getParameter("password"));
String shenfen= request.getParameter("shenfen");
Bean bean=new Bean(zhanghao,password,shenfen);
if(dao.insert(bean)) {//？
request.setAttribute("message", "添加成功");
request.getRequestDispatcher("login.jsp").forward(request, response);
}
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
String method=request.getParameter("method");
if("insert".equals(method)) {
insert(request,response);
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
5.此为jar包，直接在官网下载然后复制粘贴到 lib 里面即可
mysql-connector-java-8.0.22.jar(此为渣包的名称)
6.login.jsp代码如下（这个页面需要建立jsp页面）
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>deng_lu</title>
</head>
<body>
<%
Object message = request.getAttribute("message");
if (message != null && !"".equals(message)) {
%>
<script type="text/javascript">
alert("<%=request.getAttribute("message")%>"); //弹出对话框
</script>
<%
}
%>
<form action="servlet?method=insert" method="post">
账号：<input type="text" name="zhanghao" id="zhanghao"/><br />
密码：<input type="password" name="password"id="password" /><br />
身份：<input type="text"name="shenfen"id="shenfen"/><br />
<input type="submit" value="添加"/>
</form>
</body>
</html>
以上是在eclipse里建立的过程，接下来是第7步，也是最后一步，建表
以上是3处需要注意的地方，第一处是库名，在DBUtil中需要改，第二个是表明在dao中需要改，（建议按照如图中命名，这样就不用改代码中的表名了，如果这样，所有代码只需把数据库的密码改掉就可以了，了，）