创建第一个属于自己的JavaWeb小程序吧(创建第一个web项目)

  本篇文章为你整理了创建第一个属于自己的JavaWeb小程序吧(创建第一个web项目)的详细内容,包含有创建第一个jsp程序 创建第一个web项目 编写第一个java程序 java第一步怎么创建 创建第一个属于自己的JavaWeb小程序吧,希望能帮助你了解 创建第一个属于自己的JavaWeb小程序吧。

  INSERT INTO `user` VALUES (1, 123, 123, 女, 北京, 123);

  INSERT INTO `user` VALUES (2, 111, 111, 男, 北京, 123123);

 

 

  

  然后打开 idea 创建以下 几个目录:

  com.filter //过滤器 解决中文字符集乱码
com.util //数据库连接工具类
com.entity //实体类
com.dao //数据操作类
com.servlet //servlet类

  

  

  

  在filter下新建一个EncodingFilter用来解决中文字符集乱码,需要实现Filter接口,并且重写doFilter函数

  

package com.filter;

 

  import java.io.IOException;

  import javax.servlet.Filter;

  import javax.servlet.FilterChain;

  import javax.servlet.FilterConfig;

  import javax.servlet.ServletException;

  import javax.servlet.ServletRequest;

  import javax.servlet.ServletResponse;

  public class EncodingFilter implements Filter{

   public EncodingFilter(){

   System.out.println("过滤器构造");

   public void destroy() {

   System.out.println("过滤器销毁");

   public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {

   request.setCharacterEncoding("utf-8"); //将编码改为utf-8

   response.setContentType("text/html;charset=utf-8");

   chain.doFilter(request, response);

   public void init(FilterConfig arg0) throws ServletException {

   System.out.println("过滤器初始化");

  }

 

  

  

  

  

  然后到web.xml下进行对EncodingFilter相应的 xml配置

  

 ?xml version="1.0" encoding="UTF-8"? 

 

   web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"

   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"

   version="4.0"

   !-- 设置编码格式 --

   filter

   filter-name EncodingFilter /filter-name

   filter-class com.filter.EncodingFilter /filter-class !--全路径 从根包开始一直到类名--

   /filter

   filter-mapping

   filter-name EncodingFilter /filter-name

   url-pattern /* /url-pattern !--* 为过滤所有--

   /filter-mapping

   !-- 设置首页为登录页 首页从默认的 index.jsp 换成 login.jsp --

   welcome-file-list

   welcome-file login.jsp /welcome-file

   /welcome-file-list

   /web-app

 

  

  在util下新建一个DBconn类用来处理对数据库的连接操作(用户名和密码需要对照自己的数据库进行更改)

  

package com.util;

 

  import java.sql.*;

  public class DBConnection {

   //定义连接数据库的属性

   private static String JDBC_DRIVER = "com.mysql.jdbc.Driver";

   private static String url = "jdbc:mysql://localhost:3306/demo";

   // 用户 密码

   private static String username = "root";

   private static String pwd = "123456";

   private static Connection conn = null;

   static ResultSet rs = null;

   static PreparedStatement ps =null;

   public static void init(){

   try {

   Class.forName(JDBC_DRIVER);

   conn = DriverManager.getConnection(url,username,pwd);

   } catch (Exception e) {

   System.out.println("init [SQL驱动程序初始化失败!]");

   e.printStackTrace();

   public static int addUpdDel(String sql){

   int i = 0;

   try {

   PreparedStatement ps = conn.prepareStatement(sql);

   i = ps.executeUpdate();

   } catch (SQLException e) {

   System.out.println("数据库增删改异常");

   e.printStackTrace();

   return i;

   public static ResultSet selectSql(String sql){

   try {

   ps = conn.prepareStatement(sql);

   rs = ps.executeQuery(sql);

   } catch (SQLException e) {

   System.out.println("数据库查询异常");

   e.printStackTrace();

   return rs;

   public static void closeConn(){

   try {

   conn.close();

   } catch (SQLException e) {

   System.out.println("数据库关闭异常");

   e.printStackTrace();

  }

 

  在entity下新建一个User实体类对应数据库中的每个字段

  

package com.entity;

 

  public class User {

   private int id;

   private String name;

   private String pwd;

   private String sex;

   private String address;

   private String info;

   public int getId() {

   return id;

   public void setId(int id) {

   this.id = id;

   public String getName() {

   return name;

   public void setName(String name) {

   this.name = name;

   public String getPwd() {

   return pwd;

   public void setPwd(String pwd) {

   this.pwd = pwd;

   public String getSex() {

   return sex;

   public void setSex(String sex) {

   this.sex = sex;

   public String getAddress() {

   return address;

   public void setAddress(String address) {

   this.address = address;

   public String getInfo() {

   return info;

   public void setInfo(String info) {

   this.info = info;

  }

 

  在dao下新建一个UserDao接口 以及对应的方法实现类 规范开发 需要使用 接口及实现类

  UserDao.java

  

package com.dao;

 

  import com.entity.User;

  import java.util.List;

  public interface UserDao {

   public boolean login(String name,String pwd);//登录

   public boolean register(User user);//注册

   public List User getUserAll();//返回用户信息集合

   public boolean delete(int id) ;//根据id删除用户

   public boolean update(int id,String name, String pwd,String sex, String home,String info) ;//更新用户信息

  }

 

  在写一个 UserDaoImpl.java 实现UserDao接口,及未实现的方法

  

package com.dao;

 

  import com.entity.User;

  import com.util.DBConnection;

  import java.sql.ResultSet;

  import java.sql.SQLException;

  import java.util.ArrayList;

  import java.util.List;

  public class UserDaoImpl implements UserDao {

   DBConnection DBconn = new DBConnection();

   // 注册用户

   @Override

   public boolean register(User user) {

   boolean flag = false;

   DBconn.init();

   int i =DBconn.addUpdDel("insert into user(name,pwd,sex,address,info) " +

   "values("+user.getName()+","+user.getPwd()+","+user.getSex()+","+user.getAddress()+","+user.getInfo()+")");

   if(i 0){

   flag = true;

   DBconn.closeConn();

   return flag;

   // 查询 登录用户是否存在

   @Override

   public boolean login(String name, String pwd) {

   boolean flag = false;

   try {

   DBconn.init();

   ResultSet rs = DBconn.selectSql("select * from user where name="+name+" and pwd="+pwd+"");

   while(rs.next()){

   if(rs.getString("name").equals(name) rs.getString("pwd").equals(pwd)){

   flag = true;

   DBconn.closeConn();

   } catch (SQLException e) {

   e.printStackTrace();

   return flag;

   // 获取用户

   @Override

   public List User getUserAll() {

   List User list = new ArrayList User ();

   try {

   DBconn.init();

   ResultSet rs = DBconn.selectSql("select * from user");

   while(rs.next()){

   User user = new User();

   user.setId(rs.getInt("id"));

   user.setName(rs.getString("name"));

   user.setPwd(rs.getString("pwd"));

   user.setSex(rs.getString("sex"));

   user.setAddress(rs.getString("address"));

   user.setInfo(rs.getString("info"));

   list.add(user);

   DBconn.closeConn();

   return list;

   } catch (SQLException e) {

   e.printStackTrace();

   return null;

   // 更新用户数据

   @Override

   public boolean update(int id, String name, String pwd, String sex, String home, String info) {

   boolean flag = false;

   DBconn.init();

   String sql ="update user set name ="+name

   +" , pwd ="+pwd

   +" , sex ="+sex

   +" , home ="+home

   +" , info ="+info+" where id = "+id;

   int i =DBconn.addUpdDel(sql);

   if(i 0){

   flag = true;

   DBconn.closeConn();

   return flag;

   // 删除用户

   @Override

   public boolean delete(int id) {

   boolean flag = false;

   DBconn.init();

   String sql = "delete from user where id="+id;

   int i =DBconn.addUpdDel(sql);

   if(i 0){

   flag = true;

   DBconn.closeConn();

   return flag;

  
在servlet下创建DengluServlet用来实现对用户登录的操作 ,实现Servlet具体内容,然后需要去WEB_INF下的web.xml去配置servlet

  

package com.servlet;

 

  import com.dao.UserDao;

  import com.dao.UserDaoImpl;

  import javax.servlet.*;

  import javax.servlet.http.*;

  import javax.servlet.annotation.*;

  import java.io.IOException;

  @WebServlet(name = "signinServlet", value = "/signinServlet")

  public class Signin extends HttpServlet { // serverlet 需要继承 HttpServerlet 并重写doGet和doPost方法

   @Override

   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

   doPost(request, response); //将信息使用doPost方法执行 对应jsp页面中的form表单中的method

   @Override

   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

   String name = request.getParameter("name"); //得到jsp页面传过来的参数

   String pwd = request.getParameter("pwd");

   UserDao ud = new UserDaoImpl();

   if(ud.login(name, pwd)){

   request.setAttribute("xiaoxi", "欢迎用户"+name); //向request域中放置信息

   request.getRequestDispatcher("/success.jsp").forward(request, response);//转发到成功页面

   }else{

   response.sendRedirect("index.jsp"); //重定向到首页

  }

 

  两点要注意的地方:

  一:getParameter与getAttribute两者的区别

  request.setAttribute("xiaoxi", "欢迎用户"+name);//向request域中放置信息 ( 键值对的形式) 名字为xiaoxi 内容为"欢迎用户"+name

  request.getAttribute("xiaoxi");//得到request域中放置名字为xiaoxi的信息

  request.getParameter("name");//得到request域的参数信息(得到jsp页面传过来的参数)

  getAttribute表示从request范围取得设置的属性,必须要先setAttribute设置属性,才能通过getAttribute来取得,设置与取得的为Object对象类型 。

  getParameter表示接收参数,参数为页面提交的参数,包括:表单提交的参数、URL重写(就是xxx?id=1中的id)传的参数等,因此这个并没有设置参数的方法(没有setParameter),而且接收参数返回的不是Object,而是String类型

  二:转发与重定向的区别

  (1).重定向的执行过程:Web服务器向浏览器发送一个http响应--》浏览器接受此响应后再发送一个新的http请求到服务器--》服务器根据此请求寻找资源并发送给浏览器。它可以重定向到任意URL,不能共享request范围内的数据。
(2).重定向是在客户端发挥作用,通过新的地址实现页面转向。
(3).重定向是通过浏览器重新请求地址,在地址栏中可以显示转向后的地址。
(4).转发过程:Web服务器调用内部方法在容器内部完成请求和转发动作--》将目标资源发送给浏览器,它只能在同一个Web应用中使用,可以共享request范围内的数据。
(5).转发是在服务器端发挥作用,通过forward()方法将提交信息在多个页面间进行传递。
(6).转发是在服务器内部控制权的转移,客户端浏览器的地址栏不会显示出转向后的地址。
在servlet下创建一个ZhuceServlet用来实现用户注册的操作

  

package com.servlet;

 

  import com.dao.UserDao;

  import com.dao.UserDaoImpl;

  import com.entity.User;

  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 java.io.IOException;

  @WebServlet(name = "LogonServlet", value = "/LogonServlet")

  public class Logon extends HttpServlet{

   @Override

   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   super.doGet(req, resp);

   @Override

   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   String name = req.getParameter("name"); //获取jsp页面传过来的参数

   String pwd = req.getParameter("pwd");

   String sex = req.getParameter("sex");

   String address = req.getParameter("address");

   String info = req.getParameter("info");

   User user = new User(); //实例化一个对象,组装属性

   user.setName(name);

   user.setPwd(pwd);

   user.setSex(sex);

   user.setAddress(address);

   user.setInfo(info);

   UserDao ud = new UserDaoImpl();

   if( ud.register(user) ){

   req.setAttribute("username", name); //向req域中放置参数

   req.setAttribute("xiaoxi", "注册成功");

   req.getRequestDispatcher("/login.jsp").forward(req, resp); //转发到登录页面

   }else{

   resp.sendRedirect("login.jsp");//重定向到首页

  }

 

  在servlet下创建SearchallServlet用来返回数据库中所有用户信息Searchall.java

  

package com.servlet;

 

  import com.dao.UserDao;

  import com.dao.UserDaoImpl;

  import com.entity.User;

  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 java.io.IOException;

  import java.util.List;

  @WebServlet(name = "SearchallServlet", value = "/SearchallServlet")

  public class Searchall extends HttpServlet {

   @Override

   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   super.doGet(req, resp);

   @Override

   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   UserDao ud = new UserDaoImpl();

   List User userAll = ud.getUserAll();

   req.setAttribute("userAll", userAll);

   req.getRequestDispatcher("/showall.jsp").forward(req, resp);

  }

 

  

  在servlet下创建DeleteServlet用来删除用户操作DeleteServlet.java

  

package com.servlet;

 

  import com.dao.UserDao;

  import com.dao.UserDaoImpl;

  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 java.io.IOException;

  @WebServlet(name = "DeleteServlet", value = "/DeleteServlet")

  public class Delete extends HttpServlet {

   @Override

   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   super.doGet(req, resp);

   @Override

   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   String id = req.getParameter("id");

   int userId = Integer.parseInt(id);

   UserDao ud = new UserDaoImpl();

   if(ud.delete(userId)){

   req.setAttribute("xiaoxi", "删除成功");

   req.getRequestDispatcher("/Searchall").forward(req, resp);

   }else{

   resp.sendRedirect("index.jsp");

  }

 

  在servlet下创建UpdateServlet操作用来更新用户信息UpdateServlet.java

  

 

 

  

package com.servlet;

 

  
import javax.servlet.http.HttpServletRequest;

  import javax.servlet.http.HttpServletResponse;

  import java.io.IOException;

  @WebServlet(name = "UpdateServlet", value = "/UpdateServlet")

  public class Update extends HttpServlet {

   @Override

   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   super.doGet(req, resp);

   @Override

   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

   String id = req.getParameter("id");

   int userId = Integer.parseInt(id);

   String name = req.getParameter("name");

   String pwd = req.getParameter("pwd");

   String sex = req.getParameter("sex");

   String home = req.getParameter("home");

   String info = req.getParameter("info");

   System.out.println("------------------------------------"+userId);

   UserDao ud = new UserDaoImpl();

   if(ud.update(userId, name, pwd, sex, home, info)){

   req.setAttribute("xiaoxi", "更新成功");

   req.getRequestDispatcher("/Searchall").forward(req, resp);

   }else{

   resp.sendRedirect("index.jsp");

  }

 

  

  配置servlet

  

 ?xml version="1.0" encoding="UTF-8"? 

 

   web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"

   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"

   version="4.0"

   !-- 设置编码格式 --

   filter

   filter-name EncodingFilter /filter-name

   filter-class com.filter.EncodingFilter /filter-class !--全路径 从根包开始一直到类名--

   /filter

   filter-mapping

   filter-name EncodingFilter /filter-name

   url-pattern /* /url-pattern !--* 为过滤所有--

   /filter-mapping

  
servlet-name LogonServlet /servlet-name

   servlet-class com.servlet.Logon /servlet-class

   /servlet

   servlet

   servlet-name SigninServlet /servlet-name

   servlet-class com.servlet.Signin /servlet-class

   /servlet

   servlet

   servlet-name SearchallServlet /servlet-name

   servlet-class com.servlet.Searchall /servlet-class

   /servlet

   servlet

   servlet-name DeleteServlet /servlet-name

   servlet-class com.servlet.Delete /servlet-class

   /servlet

   servlet

   servlet-name UpdateServlet /servlet-name

   servlet-class com.servlet.Update /servlet-class

   /servlet

   !--配置Servlet 类--

   servlet-mapping

   servlet-name LogonServlet /servlet-name

   url-pattern /LogonServlet /url-pattern

   /servlet-mapping

   servlet-mapping

   servlet-name SigninServlet /servlet-name

   url-pattern /SigninServlet /url-pattern

   /servlet-mapping

   servlet-mapping

   servlet-name SearchallServlet /servlet-name

   url-pattern /SearchallServlet /url-pattern

   /servlet-mapping

   servlet-mapping

   servlet-name DeleteServlet /servlet-name

   url-pattern /DeleteServlet /url-pattern

   /servlet-mapping

   servlet-mapping

   servlet-name UpdateServlet /servlet-name

   url-pattern /UpdateServlet /url-pattern

   /servlet-mapping

   !-- 设置首页为登录页 --

   welcome-file-list

   welcome-file login.jsp /welcome-file

   /welcome-file-list

   /web-app

 

  

  

  

  

  新建jsp页面 login

  

 %@ page contentType="text/html;charset=UTF-8" language="java" % 

 

   html

   head

   title 登录页 /title

   /head

   body

   form action="SigninServlet" method="post"

   用户名: input type="text" name="name"value="" br br

   密码: input type="password" name="pwd"value="" br br

   input type="submit"value="登录"name="denglu" input type="reset"value="重置" br

   /form

   form action="zhuce.jsp"

   input type="submit"value="新用户注册"

   /form

   /body

   /html

 

  

  zhuce.jsp 用户注册页面

  

 %@ page contentType="text/html;charset=UTF-8" language="java" % 

 

   String path = request.getContextPath();

   String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

   html

   head

   title My JSP BB.jsp starting page /title

   /head

   body

   form action="LogonServlet"method="post"

   输入用户名: input name="name" type="text" br br

   输入密码: input name="pwd" type="password" br br

   选择性别: input type="radio"name="sex"value="男"checked 男

   input type="radio"name="sex"value="女" 女 br br

   选择家乡:

   select name="address"

   option value="上海" 上海 /option

   option value="北京" selected 北京 /option

   option value="纽约" 纽约 /option

   /select br

   填写个人信息: br

   textarea name="info" row="5"cols="30" /textarea br

   input type="reset"value="重置" input type="submit"value="注册"

   /form

   /body

   /html

 

  

  失败页面 index.jsp

  

 %@ page contentType="text/html;charset=UTF-8" language="java" % 

 

   html

   head

   title /title

   /head

   body

   p 失败 /p

   /body

   /html

 

  success.jsp 成功页面

  

 %@ page contentType="text/html;charset=UTF-8" language="java" % 

 

   html

   head

   title My JSP success.jsp starting page /title

   /head

   body

   ${xiaoxi} br

   a href="showall.jsp" 查看所有用户 /a

   /body

   /html

 

  

  完成以上工作就可以 运行 Tomcat服务,然后运行啦

  本博文参考大佬http://blog.csdn.net/qq_23994787/article/details/73612870

  

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