MySQL+DBUtils+C3P0+ Servlet+HTML完成Web端登陆验证案例实现

来源：互联网发布：plc编程功能块编辑：程序博客网时间：2024/06/06 02:46

1.技术分析

Web客户端采用HTML编写布局文件，利用Form表单标签完成Http请求的提交。服务器采用Tomcat服务器，利用Servlet来处理Http请求，后台数据库采用MySQL数据库，利用DBUtils+C3P0来完成JDBC操作。

图1.1 案例架构

2.技术实现步骤

2.1后台数据库创建

1.创建数据库的SQL语句:CREATE DATABASE person;

2.选择指定的数据库：USE person;

3.创建数据库表用户表（Person表）

CREATE TABLE person(id INT PRIMARY KEY AUTO_INCREMENT,

username VARCHAR(20) ,

passworld VARCHAR(20) );

4.插入数据库的SQL语句：

INSERT INTO person(id,username,passworld) VALUES(1,'nuc','123');

INSERT INTO person(id,username,passworld) VALUES(2,'bupt','123');

图2.1 数据库建表情况

2.2 Web前端的布局代码

<!DOCTYPE html><html><head><meta charset="utf-8" /><title></title><style>#username{width: 250px;}#password{margin-left: 16px;width: 250px;}</style></head><body><form action="http://localhost:8080/Web2/LoginServlet",method="post">用户名<input id="username", name="username",rrequired="true"/><br/>密码<input id="password" name="password",rrequired="true"//><br/><input type="submit",name",value="登陆"/><br/></form></body></html

图2-2 Web前端代码

2.3 服务器Servlet代码

public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{//1.设置发送数据的编码格式response.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");//2.获取请求报文中携带的数据Person person;String userName = request.getParameter("username");String password= request.getParameter("password");//3 利用DBUtils完成查询QueryRunner qr= new QueryRunner(C3P0Utils.getDataSource());String sqlString = "select * from person where username = ? and passworld=?";//String[] paramString = new String []{userName,password};//System.out.println(paramString[0]+paramString[1]);try {person =qr.query(sqlString, new BeanHandler<Person>(Person.class),userName,password);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();response.getWriter().write("登陆错误");System.out.println("登陆错误");throw new RuntimeException();}if(person!=null){System.out.println("登陆成功");response.getWriter().write("登陆成功");}else{System.out.println("账号密码错误");response.getWriter().write("账号密码错误");}}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}}注1：Person是javaBean对象，其中具有id username passworld字段，设置了相应的无参/有参，get/set方法。注2：C3P0Utils是对C3P0代码的封装，以下是其具体实现：public class C3P0Utils {public static DataSource mDataSource;static{mDataSource = new ComboPooledDataSource();}public static  Connection getConnection(){Connection connection;try {connection = mDataSource.getConnection();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();throw new  RuntimeException();}return connection;}public static DataSource getDataSource(){return mDataSource;}}

2.4 在利用好Servlet完成Http响应的时候，需要配置Web.xml文件，用来设计Servlet对应Url，这里贴出LoginServlet对应Web.xml文件配置内容

 <servlet>    <servlet-name>LoginServlet</servlet-name>    <servlet-class>com.butp.servlet.LoginServlet</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>LoginServlet</servlet-name>    <url-pattern>/LoginServlet</url-pattern>  </servlet-mapping>

2.5 利用C3P0连接池的时候，同样需要填写配置文件，以下是配置文件的内容

 <?xml version="1.0" encoding="UTF-8"?><c3p0-config>  <default-config>    <property name="driverClass">com.mysql.jdbc.Driver</property><property name="jdbcUrl">jdbc:mysql://localhost:3306/person</property><property name="user">root</property><property name="password">123</property><property name="initialPoolSize">5</property><property name="maxPoolSize">20</property>  </default-config>    <named-config name="oracle">     <property name="driverClass">com.mysql.jdbc.Driver</property><property name="jdbcUrl">jdbc:mysql://localhost:3306/person</property><property name="user">root</property><property name="password">123</property>  </named-config>  </c3p0-config>

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